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1
Coyle, Kieran. "An investigation of the role of soil micro-organisms in phosphorus mobilisation : a report submitted to fulfil the requrements of the degree of Doctor of Philosophy." Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phc8814.pdf.
2
Kim, Hak Jin. "Ion-selective electrodes for simultaneous real-time analysis for soil macronutrients." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4471.
Анотація:
Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (April 26, 2007) Vita. Includes bibliographical references.
3
PFEIFFER, CHARLES MICHAEL. "GROWTH AND NUTRITION OF MYCORRHIZAL GUAYULE IN SALINE SOILS (ENDOMYCORRHIZAE, GLOMUS INTRARADICES, SALINITY)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183780.
Анотація:
Inoculation of Parthenium argentatum (guayule) with an endomycorrhizal fungus (Glomus intraradices) increased the growth of guayule in saline and non-saline soils low in available phosphorus. Addition of 100 ug/g of P as Ca(H2PO4)2 to soils low in available phosphorus was as efficient as G. intraradices in stimulating the growth of guayule. The concentrations and total plant accumulations of minerals within guayule shoots varied depending on growth of the plants and the minerals assayed. In most cases, the concentrations of Cu, Zn, Mn, Na and Cl increased in the shoot tissues of guayule grown in soils which contained added NaCl. Generally, addition of phosphorus to the soil resulted in decreased concentrations of Cu and Zn and increased concentrations of PO4 in guayule shoots. The total accumulations of minerals by guayule was directly influenced by the biomass of plants. Increased biomass of plants generally resulted in increased total accumulations of the minerals assayed. The influence of mycorrhizae on the accumulations of minerals by guayule grown in a saline soil was evaluated by comparing nonmycorrhizal plants with the same biomass and phosphorus nutrition as mycorrhizal plants. Mycorrhizae increased the concentrations and total plant accumulations of Zn and decreased the content of Cl within guayule shoots. Colonization of guayule roots by G. intraradices was not affected by addition of P to the soil. Addition of NaCl to the soil decreased the formation of arbuscules and vesicles within roots and increased the incidence in which no fungal structures were seen. The combination of P and NaCl added to soil had a synergistic effect on the mycorrhizae of guayule. Addition of both P and NaCl to soil reduced the occurrence of hyphae, arbuscules and vesicles within roots and decreased the overall infection of guayule roots by G. intraradices.
4
Cruz, David Ricardo Jimenez. "Influence of soils, nutrition, and water relations upon charcoal rot disease processes in Kansas." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/10747.
Анотація:
Master of ScienceDepartment of Plant Pathology
Christopher R. Little
Christopher R. Little
Charcoal rot, caused by Macrophomina phaseolina, is the most important soybean disease in Kansas. Several strategies have been recommended to control this disease including crop rotation, lower plant densities, biological control, plant resistance and tolerance, and fungicide application. However, those techniques have not been completely effective and the information concerning soil texture, irrigation and micronutrient fertility (particularly manganese) upon charcoal rot disease severity and the pathogen population is limited. The objective of this study was to determine key factors that affect the biology of M. phaseolina and charcoal rot processes under laboratory, greenhouse and field conditions. M. phaseolina microsclerotia were produced from PDA pure isolate and infested Japanese millet in the laboratory and characterized by different techniques such as serial dilutions in semi selective media with the aim to produce quality inoculum to reliably infect soybean seedling roots under greenhouse conditions; production of inoculum by infesting Japanese millet was the most efficient method. Root colonization and root infection of soybean seedlings was assessed through the use of M. phaseolina inoculum under controlled conditions in the greenhouse. Root infection by M. phaseolina and microsclerotia longevity in soil is determined by environmental factors such as soil moisture content, soil texture and source of inoculum. The objective of the greenhouse study was to determine the impact of these variables on seedling root infection at the V1 and V2 development stages. Artificial soils with different textures were infested; M. phaseolina microsclerotia and soybean seedlings were exposed to different soil moisture contents including pot saturation, pot (field) capacity, and permanent wilting point. Soil populations and levels of root colonization for the stages were assessed by estimating CFUs and root length. Results indicate that soil texture has a significant impact upon root morphology and root length. Root populations of M. phaseolina were significantly higher in sandy soil textures and lower in the fine-textured soils, suggesting an impact of soil water holding capacity in the root infection process. The effect of water stress on seedling root colonization by M. phaseolina indicates that early infection may be more important than previously thought. A field study was also conducted to determine the effect of the aforementioned variables in a 2-year field experiment conducted at two Kansas locations. Pathogen colonization was iii assessed by measuring colony-forming units (CFUs) from ground root tissue at R2-R4 (post-flowering/early pod development) and R8 (maturity) stages. Soil populations (pre-planting and post-harvest) of M. phaseolina, yield parameters, and plant characteristics were obtained. Results indicated that there are complex relationships between soil physiochemical properties (pH, NPK content, exchangeable cations, and organic matter) and soil texture (sand, soil, and clay composition), which may mitigate disease severity and pathogen levels in host tissue. Results also indicated that in natural M. phaseolina-infested soils, cropping history and soil texture play an important role in charcoal rot processes and influence the levels of pathogen soil populations, root colonization at maturity and, more importantly, soybean yield.
5
Ramesh, Sunita. "Molecular mechanism of zinc uptake and regulation in cereals." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phr1724.pdf.
Анотація:
Bibliography: leaves 174-204. "This work provides a starting point for understanding the molecular mechanisms of zinc uptake and the regulation of zinc transport in cereals. Zinc efficient cereals would yield more on soild with low zinc and could potentially result in increased zinc content grain."
6
Molteno, Steve. "The characterization of Rooibos tea soils and their effects on nitrogen nutrition of the plant." Bachelor's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/26686.
7
Uribe, Botero Eduardo. "Response of corn to manganese application on Atlantic coastal plain soils." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/45679.
Анотація:
Although corn plants are tolerant of low levels of
available soil Mn, Mn deficiencies in corn were suspected on soils where Mn applications had previously increased
soybean seed yields. Five experiments were conducted
in farmer's fields to evaluate the response of
corn to Mn applications. Three band Mn and two broadcast
Mn studies were conducted in five field experiments
on Atlantic Coastal Plain soils. The mean increase in
corn grain yield in the band studies on three soils was
l
960 kg ha-1. Corn grain yields were not increased in
the broadcast Mn studies on Slagle and Dragston fine
sandy loams. Manganese uptake from the Slagle soil was
so high that Mn deficiency did not occur; whereas, Mn
uptake from the Dragston soil was so low that the deficiency
was not completely corrected by up to 24 kg Mn
hha-1 as broadcast MnSO4.Master of Science
8
Kitchen, Julie Louise. "Nutrition and nutrional value of wheat grown in organic and conventional farming systems in South Australia." Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phk618.pdf.
9
Kroehler, Carolyn J. "The role of acid phosphatases in the phosphorus nutrition of arctic tundra plants." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/80295.
Анотація:
The acid phosphomonoesterase activity associated with two major rooting strategies in arctic tundra plants was examined: that of Eriophorum vagina tum, a dominant plant in tussock tundra ecosystems, with its predominantly non-mycorrhizal root system; and that of ectomycorrhizal roots.
Eriophorum has phosphatase activity which is evenly distributed along its root surface, has a pH optimum at soil pH (3.5-4.0), and continues at substantial rates at 1 °C. Inorganic phosphorus inhibits activity only 7 to 19%. In addition, Eriophorum has phosphatase activity associated with all the "below-ground" components of its tussock growth form: dead roots, leaf sheaths, and soil. Plants with higher tissue phosphorus growing in soils with higher available phosphate in general had higher live and dead root, leaf sheath, and soil phosphatase activity in both natural and manipulated sites of higher plant productivity. Yearly and seasonal variation sometimes exceeded differences among treatments, suggesting that enzyme activity would not provide a reliable measure of plant or soil phosphorus levels. Experiments with radiolabeled inositol hexaphosphate showed that Eriophorum is able to hydrolyze and absorb inorganic phosphate from an organic phosphate source. A comparison of enzyme hydrolysis rates with inorganic phosphate assimilation rates indicates that organic phosphate hydrolysis may occur as rapidly as inorganic phosphate absorption. Inorganic phosphate released by root surface phosphatase activity could satisfy approximately 65% of the annual phosphate demand of Eriophorum.
Phosphatases of two ectomycorrhizal fungi (Cenococcum geophilum and Entoloma sericeum) responded similarly to growth in axenic culture at 2 or 50 micromolar KH₂PO₄ or sodium inositol hexaphosphate: surface Vmax estimates were significantly greater for 2 micromolar- than for 50 micromolar-grown isolates. The presence of constitutive extracellular soluble phosphatase activity resulted in the appearance of inorganic phosphate in media initially supplied only with organic phosphate. The surface acid phosphatase activity of field-collected ectomycorrhizal roots of arctic Salix and Betula, however, did not respond in a consistent way to differences in soil characteristics. Activity differed more among "color types" or fungal types than among sites of different soil characteristics.Ph. D.
10
Nuñez, Moreno Jesus Humberto. "Nutritional Studies on Pecans [Carya illinoinensis L. (Wangenh.) C. Koch] Growing in Irrigated Alkaline Soils." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194206.
Анотація:
Annual application of N at rates of 118 (118N), 236 (236N), and 354 (354N) kg•ha⁻¹ on 35 year old 'Western Schley' pecan trees during four years had little effect on mineral composition and foliar N. No differences in yield, nut quality, and reproductive characteristics were found. Alternate bearing intensity in four consecutive years was 37, 33 and 28% in 118N, 236N, and 354N, respectively, with a significant linear response. Rates from 118 to 236 kg N•ha⁻¹ satisfy N needs for pecan in irrigated pecan orchard of the southwest of United States. The effect of one-time banding of zinc sulfate (74 kg Zn•ha⁻¹) and zinc-EDTA (19 kg Zn•ha⁻¹) was evaluated over a period of four years on ‘Wichita’ pecans growing in alkaline soil. Significant differences in foliar Zn levels were found one month after application of Zinc-EDTA. Differences also were noted during the next three years on approximately 25% of the sampling dates. Yield, leaflet area, and trunk cross sectional area were not affected. Zinc-EDTA increased Zn uptake by 'Wichita' pecan trees in alkaline conditions during three years. A field study indicated that manure or manure plus Zn increased foliar Zn levels in pecans after two years of annual applications. Manure (24 ton ha⁻¹) plus zinc sulfate (258 kg Zn•ha⁻¹ as zinc sulfate) treatment had the highest foliar Zn levels. No differences were observed in trunk growth, leaf area, leaf weight, nut filling, and yield. Manganese toxicity symptoms are exhibited when leaf Mn levels are higher than 1700 μg•g⁻¹ during the standard date sampling of July and affected reproductive characteristics and leaf and shoot growth. More severe visible symptoms include delayed budbreak and die-back of young shoots. In potted pecan trees, zinc EDTA treated trees had a foliar Zn of 244 μg•g⁻¹, in foliar sprayed trees (eight foliar sprays of a combination of zinc sulfate and UAN32) had 140 μg•g⁻¹, and in control trees had 33 μg•g⁻¹. Soil adsorption isotherms showed that of the three fertilizers evaluated Zn sulfate was adsorbed most strongly by the soil (1.5 mg Zn•g⁻¹ of soil). Soil adsorption from Zn EDTA solutions was insignificant.
11
Richard, Paul François. "A computer analysis of the flow of water and nutrients in agricultural soils as affected by subsurface drainage." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29171.
Анотація:
A computer model was developed in order to determine the effects of drainage practices on nutrient losses from level agricultural soils.
The model performs a daily simulation of the vertical flow of water, nitrogen, phosphorus, and heat, and of the growth of crops. A water flow submodel calculates the depth of the water table based on daily predictions of evaporation, transpiration, flow to drains and ditches, and deep percolation. An original saturated-unsaturated flow algorithm is used to determine moisture infiltration, redistribution, and upward flow in the soil matrix, as well as bypassing flow in the soil macropores and horizontal flux between the soil matrix and the macropores, and surface runoff. Nutrient movement occurs by mass flow. Heat flow, nutrient biochemical transformations, and crop growth are determined by using well established relations.
Field tests were carried out for a period of two years on an experimental site in the Lower Fraser Valley of British Columbia. The water table depth was measured on a continuous basis. Grab samples of drainwater and observation wells were obtained periodically and analyzed for nitrogen (N0₃-N, NH₄-N, and TKN) and phosphorus (P0₄-P and TP). The field results show a decrease in the concentration of all nutrients over the sampling period, and provide evidence that denitrification and bypassing flow are important mechanisms affecting the nutrient balance of this soil.
These results were used to calibrate the model. An excellent fit of the observed water table profile and an adequate fit of the observed drain concentration of nitrate were obtained. The simulation revealed that bypassing flow is a very important transfer mechanism in this soil and must be included in order to obtain a satisfactory fit of the experimental data.
A sensitivity analysis of the model showed that the patterns of moisture flow have a predominant influence on the rate of nutrient leaching. In particular, it was found that the nutrient concentration in drain water is a strong function of the hydraulic conductivity of the soil matrix and of the horizontal distance between the soil macropores, which control the ratio of moisture flow in the soil matrix to the macropore flow and the lateral diffusion of nutrients between the soil matrix and the macropores.
The effects of four different drainage designs on nutrient losses were simulated over a period of two years for three different soils and two different nutrient distributions in the soil. It was found that there is a large difference between the amount of nutrients leached from drainage systems using different drainage coefficients. There was also a large difference in the response of two drainage designs based on the same drainage coefficient but using different depth and spacing of drains. Transient effects, as determined by the initial vertical distribution of the nutrients, were seen to remain dominant over the two year duration of the simulation.
The model was found to be useful in explaining the apparent contradictions found in the literature assessing the effects of subsurface drainage on nutrient losses. The results from the model show these effects to be strongly site and condition specific. Furthermore, the model shows that soils and drainage designs that produce similar volumes of drain flow may exhibit very different leaching responses, and that drainage designs equivalent from a hydraulic standpoint can be very dissimilar in their potential for leaching nutrients. The model provides a tool which can be used to determine the appropriateness of different drainage designs in soils where minimizing nutrient losses is critical.Science, Faculty of
Resources, Environment and Sustainability (IRES), Institute for
Graduate
12
Sikström, Ulf. "Growth and nutrition of coniferous forests on acidic mineral soils : status and effects of liming and fertilization /." Alnarp : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-6066-2.pdf.
13
Knecht, Billberger Magnus F. "Plant growth - stoichiometry and competition : theory development in ecosystem ecology /." Uppsala : Dept. of Ecology and Environmental Research, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200624.pdf.
14
Murata, Monica Rujeko. "The impact of soil acidity amelioration on groundnut production and sandy soils of Zimbabwe." Diss., University of Pretoria, 1995. http://upetd.up.ac.za/thesis/available/etd-08152003-155125.
15
Wakeel, Abdul. "Substitution of potassium by sodium in sugar beet (Beta vulgaris L.) nutrition with special reference to K-fixing soils." Giessen VVB Laufersweiler, 2008. http://d-nb.info/994756046/04.
16
Venter, Annari. "Comparing plant yield and composition with soil properties using classical and geostatistical techniques." Diss., University of Pretoria, 2003. http://hdl.handle.net/2263/23916.
Анотація:
Plant nutrient management plays a vital role in the success or failure of modern Lucerne production. In South Africa, Lucerne is produced under a wide range of climatic conditions, under dryland and irrigation and in some areas throughout the year. This means that there is a continuous demand for nutrients under a wide range of environmental conditions. The most important factors affecting the nutrient requirement of Lucerne is yield, the cutting schedule, climate and management practices. To enable site-specific crop requirements, the spatial variation of soil and plant properties within a field can be managed with the use of geostatistical techniques. Some work has also been done to evaluate the use of geostatistics in the design of agricultural field experiments to provide better field characterization and improve plot layout. The aim of this study was to compare plant yield and composition with soil properties using both classical and geostatistical techniques. The study was conducted from June 2001 to February 2002 on an 18ha Lucerne stand in the Brits district in the North West Province. A rectangular area of 160m X140m was demarcated as the study area and comprised of two soil units (Hutton and Shortlands forms). Seventy-two sampling points (nodes) were laid out on a 20m square grid, with an additional 90 sampling points laid out on a 2.5m square grid at six randomly selected node points. Soil (0-300 mm) and plant samples were taken within a 0.6m square at each of the sampling points for chemical analysis. Starting in June 2001, yield sampling was done on six occasions, at approximate intervals of 5 weeks. A randomized complete block design trail layout was superimposed on the geostatistical grid design and consisted of seven pseudo treatments, replicated four times. Basic statistical analysis were performed and spatial presentations of the variation of the plant and soil properties and Lucerne yield were made using geostatistical analyses. Analyses of variance were used to test for differences between pseudo treatments for all plant and soil properties. The two soils on the stud site, exhibited differences in certain properties, which caused a bi-modal population in the data. Poor correlations were found between plant nutrient uptake and soil properties as well as yield, with little or no resemblance when comparing their spatial distribution. This emphasizes the fact that the uptake of elements is not solely dependant on the concentrations thereof in the soil solution, but on other factors. Temporal variations in Lucerne yield were also observed. Although there were large differences in spatial variation of Lucerne yields across harvesting events, similar spatial patterns were evident. From an analysis of variance of the RCB design it was concluded that the experimental field was homogeneous enough to lay out a standard block design experiment. However, scrutiny of the structure of spatial variability of pH(H2O) revealed that the standard RCB designs did not provide homogeneous blocks with respect to soil variability. The consequent redesign of the experiment whereby all plots were randomly allocated to treatments and replications, led to dramatically different results: significant differences were obtained for plant and soil properties as a function of the pseudo treatments. From this study it is clear that spatial variability of soil and plant properties can jeopardize the results of a standard block design field experiment and it is therefore recommended that the layout of field experiments should be designed to the cognizance of the spatial variation of a soil property that correlated highly with a chosen response variate.Dissertation (MSc (Soil Science))--University of Pretoria, 2007.
Plant Production and Soil Science
unrestricted
17
Brown, Lynette. "A comparative study of the nitrogen nutrition of Proteaceae growing in limestone- and sandstone- derived soils of the Agulhas coast." Thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/26099.
18
Walsh, Brice D. (Brice David). "Mulch management systems in organic dwarf apple orchards and their effects on soil physical properties, soil nutrient availability, and tree nutrition." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55402.
Анотація:
An alternative to herbicides in dwarf apple orchards (Malus pumila Mill.) is the use of mulches. Research objectives were to compare several mulch systems (Festuca rubra L., Lupinus albus L. plus Daucus carota L.; straw, manure compost, geotextile) with soil cultivation as to soil physical properties and plant nutrient levels in soils, leaves and fruit. Studies carried out in 1992 and 1993 on three dwarf apple orchards on the Macdonald Campus of McGill University showed that straw mulch increased soil water contents and exchangeable K, but reduced exchangeable Mg compared to Festuca mulch. Straw mulch reduced soil temperatures in summer relative to geotextile or cultivation. Festuca reduced leaf N contents but increased leaf P contents-elative to geotextile treatments. Soil nitrate N contents were correlated with soil water contents, and the ratios N/Ca and K/Ca in the fruit were unaffected by treatment. Straw and geotextile mulches increased soil water content and nitrate-N levels during peak sowing periods and thus were the superior treatments.
19
Moloinyane, Siphokazi. "Bioefficacy of selected entomopathogenic fungal endophytes (Ascomycota) against grapevine mealybug (Planococcus ficus)." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2858.
Анотація:
Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018.Global demand for environmentally-friendly grapevine cultivation and pest control has necessitated an improved understanding of the relationship between soil properties and beneficial naturally occurring antagonists like entomopathogenic fungi (EPF). This group of fungi presents a viable alternative for the control of destructive pests such as the grapevine mealybug. Sixty-six soil samples were collected from 22 vineyards in the Western Cape, South Africa. The association between soil nutrient status and EPF prevalence was then examined. Fungi were isolated with methods of insect baiting and selective media. Fungal strains were identified and characterized using light microscopy and DNA analysis (ITS and BTub). In addition, fungal isolates were tested against a key grapevine pest, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) using an immersion bioassay at a concentration of 1 x 108 conidia ml-1. Twenty-three fungal strains were isolated and correspondence analysis (CA) of data indicated a positive association between fungal occurrence and moderate to high levels of soil-based macronutrients. Binomial logistic regression analysis revealed that soil N, K, Ca, Mg and S concentrations and C/N ratio were correlated with at least one EPF species. This study showed that some soil nutrient properties correspond to greater occurrence of EPF in grapevine soils. Strains of Beauvaria bassiana (Hypocreales: Clavicipitaceae) caused the highest mortalities (82% to 87%). In chapter three, I examined the effect of B. bassiana inoculation of grape plants on the infestation level of P. ficus, and the growth and volatile constituents of potted grape plants. The grapevines were inoculated with 1 x 108 conidia ml-1 of B. bassiana by drenching before experimentally infesting them with thirty P. ficus adult females. At four weeks post treatments, the fungus was re-isolated from leaves of 50% of the fungus exposed plants. No significant difference (P > 0.05) was observed in all the plant growth parameters measured in the fungus treated and control plants. Plant tissue analysis revealed markedly higher contents of Ca and Mg in leaf tissue of plants exposed to the B. bassiana relative to the control. GC-MS analyses showed that a significantly (X2=5.1; P<0.02) higher number of known anti-insect volatile compounds (9) including napthtalene were present among fungus treated plants compared to the control plants (5). However, B. bassiana did not have any significant effect on total polyphenol, alkaloid and flavonoids. Overall, treatment with fungus did not offer any protection against infestation of P. ficus. In conclusion, this is the first study to report on the isolation of indigenous entomopathogenic fungal (EPF) strains within vineyards of the Western Cape. The study revealed that inoculating grapevine plants during cultivation had a net positive effect on the production of volatile compounds in grapevines. These findings shed light on the mechanisms involved in endophytic fungus-plant-insect interactions. This study contributes valuable information to future development of ecological approaches involving EPF for insect control in vineyards and in general, agricultural settings.
20
Wakeel, Abdul [Verfasser]. "Substitution of potassium by sodium in sugar beet (Beta vulgaris L.) : nutrition with special reference to K-fixing soils / submitted by Abdul Wakeel." Giessen : VVB Laufersweiler, 2009. http://d-nb.info/993337465/34.
21
Badresingh, Vera. "Evaluation of low phytate barleys and in vitro procedure for predicting phosphorus availability in organic and inorganic sources of phosphorus /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3025597.
22
Gianfrancesco, Richard Umberto. "Phosphorus nutrition of mycorrhizal and non-mycorrhizal plants of upland soils with special reference to the utilization of the phosphodiester DNA under sterile conditions." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299580.
23
Singbo, Arnaud. "The effect of zinc and soil ph on grain yield and nutrient concentrations in spring wheat cultivated on potted soil." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2845.
Анотація:
Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2018.Zinc deficiency on various soil types have been reported in arable soils of sub Saharan Africa (SSA) including South Africa. A pot trial was conducted at the Cape Peninsula University of Technology, Wellington campus to investigate the interaction of different application rates of Zn at various soil pH on the grain yield and quality of spring wheat in a completely randomized factorial design replicated three times. The four soil pH tested were: pHA: 5.1, pHB: 5.6, pHC: 6.1, pHD: 6.6 which correspond to lime application at 0, 0.5, 1 and 1.5 t/ha. Five Zn rates (Zn1: 3.5; Zn2: 4.5; Zn3: 5.5 Zn4: 6.5, and Zn5: 7.5 mg /kg soil which correspond to Zn1: 7; Zn2: 9; Zn3: 11; Zn4: 13 and Zn5: 15 kg /ha) were applied at two (planting and flowering) growth stages. Yield and yield component data collected were analyzed using SAS version 9.2 and means were separated by Duncun’s Multiple Range Test (DMRT). The results showed that grain yield and yield components were significantly affected by lime application pHC (6.1): 1t/ha at planting. Zn application at planting had no significant effect on the grain yield and yield components. However, at flowering, the simultaneous increase of Zn along with increase in lime positively affected grain yield and yield components. Plant analysis showed that at both stages (planting and flowering), Zn application, especially at pH 6.6, significantly increased P, K, Ca, Na, Mg Fe, Cu and B concentrations in wheat grain, but the concentrations of N, Mn, Zn and protein remained unaffected. Zn application had no effect on most nutrients due to the presence of lime. While the absence of lime, Zn4: 6.5mg/kg (corresponding to 13kg/ha) significantly increased the nutrients. In addition, Zn3: 5.5mg/kg (corresponding to 11kg/ha) promoted Zn absorption by grain in all treatments.
24
Soratto, Rogério Peres [UNESP]. "Aplicação de calcário e gesso em superfície na implantação do sistema de plantio direto." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/100003.
Анотація:
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Existe interesse na busca de alternativas para a implantação do sistema de plantio direto em áreas anteriormente cultivadas no sistema convencional de preparo do solo ou sob pastagens, sem a incorporação prévia do calcário, realizando-se a calagem superficialmente desde o estabelecimento do sistema, desde que não haja impedimento físico ao crescimento radicular. Nesse sentido, o gesso agrícola, por ser mais solúvel e apresentar relativa mobilidade no solo, é apontado como alternativa para correção das camadas subsuperficiais do solo em curto prazo, podendo ser utilizado como um produto complementar ao calcário. Dessa forma, o trabalho objetivou avaliar a influência da aplicação superficial de calcário e gesso, na implantação do sistema de plantio direto, sobre as características químicas do solo, o teor de cátions solúveis na parte aérea das culturas, o crescimento radicular, a nutrição e produtividade de culturas anuais, em região de inverno seco. O experimento foi conduzido nos anos agrícolas de 2002/2003 e 2003/2004, na Fazenda Experimental Lageado, localizada no município de Botucatu (SP), em um Latossolo Vermelho distroférrico, anteriormente conduzido no sistema convencional de preparo do solo. O delineamento experimental foi em blocos casualizados com parcelas subdivididas e quatro repetições. As parcelas foram constituídas por quatro doses de calcário dolomítico (0, 1.100, 2.700 e 4.300 kg ha-1), com PRNT = 71,2%, visando elevar a saturação por bases para 50%, 70% e 90%, respectivamente. As subparcelas foram constituídas pela ausência e aplicação de 2.100 kg ha-1 de gesso agrícola (6 x teor de argila em g kg-1, na camada de 0,20-0,40 m de profundidade). Para as culturas de verão foi utilizado o esquema de parcelas subsubdivididas, sendo as subsubparcelas constituídas por dois cultivares de arroz de terras altas...
There is great interest to search alternatives to establish the no-tillage system in fields previously cultivated on conventional tillage or on pasture, with no lime previous incorporation, using superficial liming since the beginning of system, if don't have physical impediment to root growth. Thus, the phosphogypsum, that is more soluble and with high mobility, has been an alternative to correct the subsuperficial soil layer, in a short time, and can be used as a lime complementary product. Therefore, the objective of this work was to evaluate the effects of lime and phosphogypsum surface application during the establishment of no-tillage system, on the soil chemical characteristics, on the content of water-soluble cations, in the crop shoot, on the root growth, on the nutrition and yield of annual crops, in a dry winter region. The experiment was carried out during the agricultural years of 2002/03 and 2003/2004, in an experimental area located in Botucatu County, São Paulo State, Brazil (48º 23' W and 22º 1' S) on a Haplorthox, before used with conventional tillage system. A randomized complete block design, in split-plot scheme, and four replications was used. The plots were composed by four dolomite limestone levels (0; 1,100; 2,700; and 4,300 kg ha-1), with Neutralization Power = 84.3% and Reactivity = 84.5%, aiming raise the base saturation to 50%, 70%, and 90%, respectively. The subplots were composed by without and with phosphogypsum application (2,100 kg ha-1 = 6 x clay content (g kg-1) in 0.20-0.40 m depth layer). For the summer crops a split-split-plot scheme were used. The subsubplots were constituted by two upland rice cultivars ('Caiapó' and 'IAC 202'), on agricultural year of 2002/03, and two common bean cultivars ('Carioca' and 'Pérola'), on agricultural year of 2003/2004. In the winter season of 2003 and 2004, the black oat was grown in the area... (Complete abstract click electronic access below)
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Sousa, Adervan Fernandes. "Mineralization of nutrients and plant growth in soils irrigated with wastewater from oil extraction." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16918.
Анотація:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoO grande volume de Ãgua utilizado na agricultura compromete a sua disponibilidade para o consumo humano. Diante desse problema, Ã necessÃrio avaliar a utilizaÃÃo de Ãguas residuais na produÃÃo agrÃcola, como uma opÃÃo para a conservaÃÃo dos recursos hÃdricos. Ãguas residuais oriundas de campos de petrÃleo podem ser uma boa opÃÃo para irrigaÃÃo, especialmente em regiÃes de pouca e alta variabilidade de chuvas como o Nordeste brasileiro. No entanto, Ã necessÃrio avaliar os seus efeitos no solo, como acÃmulo de nutrientes e decomposiÃÃo da matÃria orgÃnica, bem como no aspecto nutricional e no crescimento das plantas. Os objetivos deste trabalho foram: i) Avaliar as mudanÃas ocorridas nos sais solÃveis e nas fraÃÃes da matÃria orgÃnica do solo e no crescimento de plantas de girassol (Helianthus annuus L.) cv. BRS 321, cultivadas em solo de textura arenosa irrigado com Ãgua residual oriunda da extraÃÃo de petrÃleo tratada por filtragem e osmose reversa; ii) Avaliar as alteraÃÃes nutricionais do girassol (Helianthus annuus) BRS 321 irrigado com Ãgua residual da extraÃÃo de petrÃleo e os efeitos sobre a produÃÃo de biomassa e de aquÃnios; e iii) Avaliar a decomposiÃÃo dos restos culturais de girassol (Helianthus annuus) cv. BRS 321 em Ãreas irrigadas com Ãgua residual da extraÃÃo de petrÃleo. O girassol foi cultivado durante trÃs perÃodos sucessivos em Ãreas irrigadas com Ãgua residual da extraÃÃo de petrÃleo tratada por filtragem (APF) e por osmose reversa (APO) ou Ãgua subterrÃnea do aquÃfero AÃu (ACA). Ao fim de cada ciclo foram determinados os valores de pH, condutividade elÃtrica (CE), a razÃo de adsorÃÃo de sÃdio (RAS) e os teores de Na, Cl, Mg, Ca, K, HCO3-, Ag, As, B, Ba, Cd, Co, Cr3+, Hg, Ni, Pb, Zn, alÃm de C nas fraÃÃes hÃmicas. Em raÃzes, parte aÃrea e aquÃnios determinaram-se os teores de N, P, K, Ca, Mg, S e Na e avaliaram-se o crescimento e o acÃmulo de biomassa. AlÃm disso, avaliou-se a decomposiÃÃo dos resÃduos da parte aÃrea das plantas de girassol. Houve alteraÃÃes nos atributos quÃmicos do solo, em destaque o acrÃscimo de sais, que foi maior nas Ãreas irrigadas com APF, e elevaÃÃo do pH, independente do tipo de Ãgua utilizado. A elevaÃÃo da salinidade e alcalinidade do solo reduziu o crescimento e o acÃmulo de biomassa das plantas. AlÃm disso, a irrigaÃÃo proporcionou alteraÃÃes nutricionais das plantas, que refletiram no crescimento e na produÃÃo de aquÃnios do girassol e na decomposiÃÃo dos resÃduos da cultura, com efeitos positivos ou negativos, conforme o tratamento da Ãgua residual. Concluiu-se que a Ãgua residual da extraÃÃo de petrÃleo utilizada na irrigaÃÃo afeta os atributos quÃmicos do solo, bem como a composiÃÃo nutricional e o desenvolvimento das plantas, principalmente quando irrigadas com a APF. AlÃm disso, a irrigaÃÃo com Ãgua residual alterou a mineralizaÃÃo dos resÃduos vegetais do girassol, mas nÃo a de decomposiÃÃo do carbono orgÃnico nas fraÃÃes hÃmicas.
The large volume of water used in agriculture compromises its availability for human consumption. Faced with this problem, it is necessary to evaluate the use of wastewater in agricultural production as an option for the conservation of water resources. Wastewater from oil fields can be a good choice for irrigation, especially in regions of low or high rainfall variability, as in the Brazilian Northeast. However, it is necessary to evaluate its effects on the soil, such as the accumulation of nutrients and decomposition of organic matter, as well as the nutritional aspect and plant growth. The aims of this study were: i) to assess the changes that take place in the soluble salts and soil organic matter fractions, and in the growth of plants of the BRS 321 cultivar of the sunflower (Helianthus annuus L.) cultivated in soil of a sandy texture and irrigated with wastewater obtained from oil extraction and treated by filtration and reverse osmosis; ii) to assess the nutritional changes in the BRS 321cultivar of the sunflower (Helianthus annuus) irrigated with wastewater from oil extraction, and the effects on biomass and achene production; and iii) to evaluate the decomposition of plant residue from the BRS 321 cultivar of the sunflower (Helianthus annuus) in areas irrigated with wastewater from oil extraction. The sunflower was grown for three successive periods in areas irrigated with wastewater from oil extraction treated by filtering (APF) and reverse osmosis (APO), or with groundwater from the AÃu aquifer (ACA). At the end of each cycle, pH values were determined, together with electrical conductivity (EC), the sodium adsorption ratio (SAR) and the levels of Na, Cl, Mg, Ca, K, HCO3-, Ag, As, B, Ba, Cd, Co, Cr3+, Hg, Ni, Pb, Zn, and of C in the humic fractions. The concentrations of N, P, K, Ca, Mg, S and Na were determined in the roots, shoots and achenes, along with growth and the accumulation of biomass. In addition, the decomposition of shoot residue from the sunflower plants was evaluated. Changes were seen in the chemical properties of the soil, highlighting an increase in salts, which was greater in the areas irrigated with APF; a rise was also seen in pH irrespective of the type of water used. The rise in soil salinity and alkalinity reduced the growth and accumulation of plant biomass. Moreover, irrigation resulted in nutritional changes in the plants, which were reflected in the growth and production of achenes, and in the decomposition of the plant residue, having positive or negative effects according to the treatment of the wastewater. It was concluded that wastewater from oil extraction used in irrigation affects the chemical properties of the soil as well as the nutritional composition and development of the plants, especially when irrigated with APF. Furthermore, irrigation with wastewater changed the mineralisation of the sunflower plant residue, but not the decomposition of the organic carbon in the humic fractions.
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Payn, Timothy William. "The effects of magnesium fertiliser and grass on the nutrition and growth of P. radiata planted on pumice soils in the central North Island of New Zealand." Thesis, University of Canterbury. Forestry, 1991. http://hdl.handle.net/10092/7144.
Анотація:
This thesis addressed the problem of the widespread occurrence of magnesium deficiency in Pinus. radiata planted on pumice soils in the central North Island of New Zealand, the increased severity of the deficiency where trees were planted on grassed sites, and the slow increase in foliar Mg concentrations and tree growth following fertilisation of deficient trees with various sources and rates of Mg fertiliser.
Plant available Mg concentrations were found to be very low in pumice soils, with soil solution concentrations often below 1 mgL-¹, and exchangeable concentrations in the upper 20 cm of the soil normally well below 1 meq 100g-¹. Published soil critical levels for a number of crops fall into the range of 0.2 to 1.0 meq100g-¹. Addition of between 100 and 400 kgha-¹ Mg (as Epsom salts, dolomite, or calcined magnesite) in a laboratory study raised soil solution concentrations by between 8 and 37 mgL-¹ and exchangeable concentrations by between 1.5 and 3.4 meq100g-¹. These levels should be adequate for tree growth. Epsom salts caused a much greater increase in solution Mg concentration than either dolomite or calcined magnesite.
Changes in soil solution and exchangeable concentrations were monitored in a field experiment. Epsom salts and calcined magnesite were added at 400 kgha-¹ Mg. The Epsom salts caused a large and rapid increase in solution Mg concentrations to a soil depth of at least 45 cm. Calcined magnesite had no significant effect on solution concentrations. Both treatments increased exchangeable Mg concentrations well above 1 meq100g-¹, although the less soluble calcined magnesite was slower acting. Improvements in exchangeable Mg were still apparent after 18 months with concentrations of the order of 1.5 meq100g-¹ in the upper 20 cm, although soil solution concentrations had returned to pre- fertilisation levels.
The effects of Mg deficiency on dry matter allocation patterns were investigated in a glasshouse and a field experiment. Mg deficiency caused a 25% decrease in root: shoot ratio in seedlings. In an 8 year old stand of trees, where above ground dimensions were the same, but foliar concentrations were above or below the critical level of 0.07% Mg, there was 50% less fine root length in the deficient trees when compared to the healthy. This root decline could explain the slow response of fertilised trees, either due to a smaller exploitable soil volume, or due to a need to rebuild the root system before a response is detectable above ground.
Two field experiments using 400 kgha-¹ Mg as Epsom salts were established, one in a newly planted area (Halls), and the other in an 8 year old Mg deficient P. radiata stand (Kiorenui). At this high rate foliar Mg concentrations were improved to well above 0.1% within six months of Mg application. This indicated that previous slow responses were likely to have been due to use of low rates or slowly soluble sources of Mg. No growth responses were recorded in either trial, the juvenile trees were only marginally deficient by age 3, and the older trees were measured only six months after fertiliser application.
Foliage analysis and tests with a total spectrum fertiliser indicated no other elements were deficient in either of the field experiments.
The effect of grass on tree growth and Mg uptake was tested at Halls in the juvenile trees. Removal of grass competition caused a 30% improvement in tree biomass at age 3, 18 months after treatments were applied. Grass competition intensified the Mg deficiency in the trees and if trees were fertilised without grass control, tree growth was slightly suppressed due to stimulation of the grass. It was suggested that this was an effect on the soil moisture conditions and hence nutrient uptake rather than a direct effect of the grass in competition for Mg.
The Barber-Cushman nutrient uptake model was used for a sensitivity analysis of parameters affecting Mg uptake on the newly planted site. This showed that root growth and Mg influx parameters were most important on this site, suggesting that Mg supply was not limiting growth, a conclusion supported by the fertiliser experiment results. Calculation of Mass Flow Coefficients indicated that far more Mg would be supplied to the root than would be assimilated by the tree.
Calculation of Mass Flow Coefficients from published data for an age range of P. radiata up to age 12 showed that on a site with low soil solution Mg concentration (0.3-0.5 mgL-¹), once the trees were older than 3 years the proportion of Mg supplied to the root by diffusion increased until by age 5 approximately 75% would be supplied by that means. The importance of soil diffusion rates and soil moisture conditions will therefore be greater for older trees. A soil solution concentration of 1-2 mgL-¹ was calculated to be the level at which 100% of Mg would be supplied by mass flow, and this could be used for identifying potentially deficient sites,
Conclusions from this study, plus other published information on the topic were synthesised into a set of rules. These will be the basis of an expert system for managing the Mg nutrition of P. radiata.
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Ben, Harrath Beya. "Contribution à l'étude du désherbage et de la nutrition minérale foliaire du maïs fourrager (Zea mays L.) dans les sols calcaires tunisiens." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210616.
Анотація:
L’objectif de ce travail est d’améliorer la productivité du maïs fourrager (Zea mays L.) dans les sols calcaires tunisiens. En effet dans ces conditions édaphiques la plante se heurte à des problèmes d’ordre nutritionnel limitant l’absorption des 3 éléments essentiels.C’est pourquoi nous voulons mettre au point une nouvelle technologie capable de contourner ces contraintes. En effet la fertilisation par voie foliaire associé à un désherbage de pré émergence serait l’approche la plus logique, capable d’apporter les éléments en fonction des besoins de la plante et de constituer par conséquent une alternative à des apports traditionnels au sol qui présentent un faible coefficient d’efficacité.
Pour cela nous voulons :
- étudier l’effet de la dose, de la dilution de l’engrais et de son association à un herbicide de post émergence sur la biomasse et l’absorption des éléments nutritifs de la plante et comparer ces effets à ceux d’une application traditionnelle au sol.
- Déterminer l’équilibre NPK permettant d’obtenir une croissance optimale de la plante et ceci par le biais d’une expérimentation de type factoriel.
- Enfin transposer ce mode de fertilisation en conditions réelles au champ, en intégrant également un désherbage de post émergence.
Enfin rechercher et doser, les deux molécules présentes dans l’herbicide, dans deux substrats (le sol et la plante) et étudier leur rétention à court terme :caractérisation des mécanismes d’adsorption et de désorption des deux molécules dans les deux types de sol utilisés.
Les résultats obtenus en conditions contrôlées ont mis en évidence le fait que la biomasse de la plante ainsi que la quantité d’éléments exportés par celle-ci sont gouvernées par un effet variétal et un effet dose. De plus certaines associations herbicide-engrais favorisent mieux que d’autres la croissance de la plante ainsi que l’absorption des éléments appliqués.
Les résultats de l’expérience de type factoriel ont montré qu’à doses égales, l’effet positif d’un apport foliaire est supérieur à celui de l’engrais apporté au sol. Ces effets positifs sont observés sur les différents paramètres étudiés (biomasse, absorption d’éléments, nutritifs, quantités exportés et coefficients apparents d’utilisation des 3 éléments appliqués).
L’utilisation du logiciel SPSS montre que la relation de la biomasse (poids sec) et la quantité d’éléments apportée est de type polynomial. L’équation ainsi obtenue nous a permis de calculer la production de matière sèche et de représenter les différentes surfaces de réponse.
Les résultats obtenus en conditions réelles, au champ ont montré également que l’engrais apporté sur le feuillage est le mode de fertilisation le plus efficient. Ces résultats ont montré également que pour tous les traitements, la quantité d’azote exporté par la plante, suit une courbe unimodale avec un maximum situé au prélèvement III, effectué 34 jours après le semis. Par contre les quantités de P et les quantités de K exportés augmentent de façon continue, depuis le prélèvement I (26 jours après le semis) jusqu’à la récolte finale (97 jours après le semis). C’est (l’épi +tige) qui exporte la plus grande quantité (pratiquement le double). Un effet pompe dû au traitement foliaire a été également observé. Cet effet stimule l’absorption des éléments nutritifs par les racines et permet une meilleure valorisation des réserves du sol.
En plus le désherbage de post émergence associé à l’engrais a montré une plus grande efficacité à l’égard de la flore adventice présente, en comparaison à l’application de l’herbicide seul ou associé à l’engrais appliqué au sol.
Le dosage des deux molécules herbicides en HPLC a montré que les teneurs des 2 molécules dans la plante et dans le sol sont inférieures à la limite de détermination.
(les limites de détection et de détermination ont été estimées respectivement à de valeurs de 0,02 et de 0,05 mg/kg de sol). Les coefficients de corrélation des droites d’étalonnage obtenues, sont supérieurs à 0,99 et le pourcentage de recouvrement se situe entre 84 et 104% (intervalle de confiance est de plus ou moins 18%).
Les isothermes d’adsorption obtenues dans le cas du 2,4-D sont respectivement de type L avec Kf = 0,9 et n inférieur (sol A) et de type C, avec Kf = 0,8 et n voisin de 1 (sol B). Ces résultas montrent qu’en présence d’un pH (alcalin), la molécule entant qu’acide faible est dissociée. Cette forme est peu retenue par les colloïdes du sol ce qui favorise son transfert ainsi que sa dégradation.
La normalisation, du coefficient de distribution Kd, à la teneur en matière organique et à la teneur en carbone organique montre que pour des horizons de 0-30, 30 – 60 et 60 -120 cm, les valeurs de KOM et KOC dans le sol A, restent pratiquement identiques dans les 3 horizons. Par contre dans le sol B ces coefficients sont plus faibles dans l’horizon supérieur (0-30 cm).
Par contre les isothermes d’adsorption de la carfentrazone ont mis en évidence l’absence de celle-ci et par conséquent la conversion de molécule en ses métabolites.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
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Guimarães, Claudiney do Couto. "BIOMASSA E NUTRIENTES EM PLANTIOS DE EUCALIPTOS NO BIOMA PAMPA." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/8729.
Анотація:
The silviculture with exotic species is present in most Brazilian s Biomes. In the Pampa
Biome RS, although historical records indicate the presence of eucalyptus since 1835,
commercial plantations in the southwest of the state for industrial purposes have received the
largest investments since 2000. For being an eucalyptus rapid growth and consequently high
biomass production and nutrient accumulation, debates are always being provoked to discuss
the impacts and sustainability of culture. Given the importance of this scene this study aimed
to characterize nutritionally stands of Eucalytpus grandis, Eucalyptus dunnii and hybrid of
Eucalyptus urophylla x Eucalyptus grandis (E. urograndis), with four years and six months
age, and contribute to the adequacy of nutritional management in eucalypt plantations in
Pampa Biome region. The soil in the study area is rated as Ultisol. Three sample units of 10
ha were surveyed and inventoried, one unit for each species, where a total of 27 trees (9 trees
per species), sectioned into compartments, sampling were felled for determination of tree
biomass and nutrient contents. Planting with E. urograndis showed higher biomass (158.1 Mg
ha-1), followed by E. grandis (136.7 Mg ha-1) and E. dunni (121.9 Mg ha-1), with an average
distribution to compartments 66% wood, 15% root, branch 9%, 7% bark and 4% leaf. The
total stock of nutrients in biomass (macro and micro) was: E. urograndis - 1232 kg ha-1 and
26 kg ha-1; E. grandis - 1289 kg ha-1 and 48 kg ha-1; E. dunnii - 1213 kg ha-1 and 61 kg ha-1,
respectively. The largest stock of N was found in leaves to E. grandis and E. dunnii, and
steam to E. urograndis. With the harvesting of stem wood, 63% N, 70% P, 47% K, 91% Ca,
73% Mg, 34% B and 46% S, 41% Cu, 38% Fe, 87% Mn, 38% Zn, are returned to the soil by
the other biomass components and provides the lowest nutrient removal system. Nutrient
removal, on average, according to the scenario of harvest showed the following distribution
trend: Wood Steam over Bark + Crown and the Steam over Bark Ca > K > N > Mg > S > P,
only Wood Steam K > N > S > Ca > Mg > P, for micronutrients in all scenarios harvest Mn >
Fe > Zn > B > Cu. These species showed the same magnitude of biomass allocation in
different components (stem wood > root > branch > bark > leaf). E. urograndis had the
highest wood production as well as efficiency in using nutrients. P was the element that
provided better nutritional efficiency by species. K and S were the elements that presented the
greatest risk of productivity limiting, based on the removal of nutrients in different scenarios
of biomass harvesting, nutrient balance and potential number of rotations.A silvicultura com espécies exóticas se encontra presente na maioria dos Biomas Brasileiros. No Bioma Pampa do RS, apesar dos registros históricos indicarem a presença do eucalipto desde 1835, as plantações comerciais no sudoeste do estado para fins industriais passaram a receber os maiores investimentos a partir de 2000. Por ser o eucalipto uma espécie de rápido crescimento, e consequentemente com alta produção de biomassa e acúmulo de nutrientes, debates estão sempre sendo provocados para discutir os impactos e a sustentabilidade da cultura. Diante da importância deste cenário este trabalho teve como objetivo caracterizar nutricionalmente povoamentos de Eucalytpus grandis, Eucalyptus dunnii e híbrido Eucalyptus urophylla x Eucalyptus grandis (E. urograndis), com quatro anos e seis meses de idade, e contribuir para a adequação do manejo nutricional em plantações com eucalipto na região do Bioma Pampa. O solo na área do estudo é classificado com Argissolo Vermelho distrófico típico. Foram inventariadas três unidades amostrais de 10 ha, sendo uma unidade para cada espécie, onde foram derrubadas um total de 27 árvores (9 árvores por espécie), seccionadas em compartimentos, retirado amostras para determinação da biomassa arbórea e dos teores dos nutrientes. O plantio com E. urograndis apresentou maior biomassa (158,1 Mg ha-1), seguido pelo E. grandis (136,7 Mg ha-1) e E. dunni (121,9 Mg ha-1), com distribuição média para os compartimentos de 66% madeira, 15% raiz, 9% galho, 7% casca e 4% folha. O estoque total de nutrientes na biomassa (macro e micro) foi: E. urograndis 1232 kg ha-1 e 26 kg ha-1; E. grandis 1289 kg ha-1 e 48 kg ha-1; E. dunnii 1213 kg ha-1 e 61 kg ha-1, respectivamente. O maior estoque de N foi verificado nas folhas, para E. grandis e E. dunnii, e no tronco para E. urograndis. Com a colheita da madeira do tronco, 63% N; 70% P; 47% K; 91% Ca; 73% Mg; 34% S e 46% B; 41% Cu; 38% Fe; 87% Mn; 38% Zn; são devolvidos ao solo pelos demais componentes da biomassa e proporciona a menor remoção de nutrientes do sistema. A remoção de nutrientes, em termos médios, de acordo com o cenário de colheita apresentou a seguinte tendência de distribuição: Madeira do Tronco c/c + Copa e Madeira do Tronco com Casca Ca > k > N > Mg > S > P, apenas a Madeira do Tronco K > N > S > Ca > Mg > P, para os micronutrientes em todos os cenários de colheita Mn > Fe > Zn > B > Cu. As espécies avaliadas apresentaram a mesma magnitude de alocação de biomassa nos diferentes componentes (madeira do tronco > raiz > galho > casca > folha). E. urograndis apresentou a maior produção de madeira, bem como a melhor eficiência no uso dos nutrientes. P foi o elemento que proporcionou a melhor eficiência nutricional pelas espécies. K e S foram os elementos que apresentaram os maiores riscos de limitação da produtividade, com base na remoção de nutrientes nos diferentes cenários de colheita da biomassa, balanço nutricional e número potencial de rotações.
29
Boucher, Patricia. "Base cation immobilization in the stem of some hardwoods of southern Québec." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ55039.pdf.
30
Teklay, Tesfay. "Organic inputs from agroforestry trees on farms for improving soil quality and crop productivity in Ethiopia /." Umeå : Dept. of Forest Ecology, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/2005122.pdf.
31
Dupuy, Joan. "Interactions entre les hydrocarbures aromatiques polycycliques et les plantes supérieures : prélèvement et réponses toxiques." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0299/document.
Анотація:
En France et en Europe, la fin des activités industrielles liées à l’exploitation du charbon a laissé de nombreux sites et sols pollués par les hydrocarbures aromatiques polycycliques (HAP). La rhizodégradation pourrait permettre leur dépollution par l’utilisation de plantes et de leur microflore associée. Toutefois, l’efficacité de cette technique, démontrée en conditions contrôlées de laboratoire, est limitée in situ par de fortes mortalités ou l’inhibition de croissance de la plante. De plus, le transfert de ces polluants dans la plante peut menacer la chaîne alimentaire. Ce travail se propose d’étudier les interactions entre le maïs, choisi ici comme plante modèle, et les HAP de sols industriels contaminés ou un de leur représentant, le phénanthrène ajouté à un substrat simplifié. Le prélèvement des HAP et leur effet sur la physiologie de la plante sont évalués sur des systèmes de complexité croissante et en abordant ces questions à différentes échelles, allant de la cellule à la plante entière. Il s’agit en particulier d’élucider les mécanismes de transfert et de translocation des HAP dans la plante et d’identifier les réponses toxiques de celle-ci. Les résultats mènent à l’hypothèse d’une sorption physique des HAP de la phase solide du sol par contact direct avec les racines comme mécanisme principal d’entrée et non par transport dans la phase aqueuse. Les principaux arguments sont les distributions moléculaires similaires entre les HAP totaux dans les terres et celles dans les racines, les mauvaises corrélations entre les concentrations en HAP dissous dans l’eau porale et les racines, ainsi que la surestimation des concentrations prédites par des modèles existants fondés sur un prélèvement de la solution du sol. La localisation du PHE dans les racines à l’aide d’outils de microscopie montre une subérification précoce de l’exoderme et l’endoderme, même à de faibles teneurs (50 mg kg-1). Le prélèvement de nutriment ne semble pas affecté mais d’importantes accumulations et carences d’éléments sont observées dans les parties aériennes. Ces perturbations nutritionnelles du maïs pourraient affecter le fonctionnement de la plante et par conséquent limiter sa croissance ou entraîner sa mortIn Europe and France, the end of industrial activities associated to coal exploitation left numerous wastelands contaminated with polycyclic aromatic hydrocarbons (PAH). Rhizodegradation enables their remediation by using plants associated with microflora. However, the efficiency of this technique, demonstrated at the laboratory scale, is often limited in situ by high plant mortality or inhibited growth. Furthermore, the PAH uptake in plants may threaten the food chain. This work studied the interactions between maize, chosen as model plant, and PAH from industrial contaminated soils or from simplified model systems, i.e. sand spiked with phenanthrene. PAH uptake and their effect on the plant physiology were assessed using systems of increasing complexity, to solve questions raised at different scales, from the cell to the whole plant. Mechanisms involved in PAH uptake and translocation are proposed and the toxic responses of the plant are detailed. Results lead to a new hypothesis: PAH from the solid phase penetrate the roots by physical and direct contact and not only through uptake in pore water. Main arguments are: similar molecular distributions in soils and roots, low correlations between PAH concentrations in pore water and roots and overprediction of bioaccumulation by using predicting models based on root absorption in soil solution. Localization of PHE in roots using microscopic tools showed early suberisation of endoderm and exoderm in presence of PHE, even at low concentration (50 mg kg-1). Nutrient uptake seemed not affected but large elements accumulations and depletion were observed in aerial part of maize. These nutritional disruptions may affect plant functioning and consequently, decrease its growth or even cause its death
32
Lotfollahi, Mohammad. "The effect of subsoil mineral nitrogen on grain protein concentration of wheat." Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phl882.pdf.
Анотація:
Copy of author's previously published work inserted. Bibliography: leaves 147-189. This project examines the uptake of mineral N from the subsoil after anthesis and its effect on grain protein concentration (GPC) of wheat. The overall objective is to examine the importance of subsoil mineral N and to investigate the ability of wheat to take up N from the subsoil late in the season under different conditions of N supply and soil water availability. Greenhouse experiments investigate the importance of subsoil mineral N availability on GPC of wheat and the factors that contribute to the effective utilisation of N. The recovery of N from subsoil, the effect of split N application on GPC and short term N uptake by the wheat at different rooting densities are also studied.
33
Soratto, Rogério Peres 1976. "Aplicação de calcário e gesso em superfície na implantação do sistema de plantio direto /." Botucatu : [s.n.], 2005. http://hdl.handle.net/11449/100003.
Анотація:
Orientador: Carlos Alexandre Costa CrusciolBanca: Ciro Antonio Rosolem
Banca: Godofredo Cesar Vitti
Banca: Domingos FornasieriFilho
Banca: Luis Reynaldo F. Alleoni
Resumo: Existe interesse na busca de alternativas para a implantação do sistema de plantio direto em áreas anteriormente cultivadas no sistema convencional de preparo do solo ou sob pastagens, sem a incorporação prévia do calcário, realizando-se a calagem superficialmente desde o estabelecimento do sistema, desde que não haja impedimento físico ao crescimento radicular. Nesse sentido, o gesso agrícola, por ser mais solúvel e apresentar relativa mobilidade no solo, é apontado como alternativa para correção das camadas subsuperficiais do solo em curto prazo, podendo ser utilizado como um produto complementar ao calcário. Dessa forma, o trabalho objetivou avaliar a influência da aplicação superficial de calcário e gesso, na implantação do sistema de plantio direto, sobre as características químicas do solo, o teor de cátions solúveis na parte aérea das culturas, o crescimento radicular, a nutrição e produtividade de culturas anuais, em região de inverno seco. O experimento foi conduzido nos anos agrícolas de 2002/2003 e 2003/2004, na Fazenda Experimental Lageado, localizada no município de Botucatu (SP), em um Latossolo Vermelho distroférrico, anteriormente conduzido no sistema convencional de preparo do solo. O delineamento experimental foi em blocos casualizados com parcelas subdivididas e quatro repetições. As parcelas foram constituídas por quatro doses de calcário dolomítico (0, 1.100, 2.700 e 4.300 kg ha-1), com PRNT = 71,2%, visando elevar a saturação por bases para 50%, 70% e 90%, respectivamente. As subparcelas foram constituídas pela ausência e aplicação de 2.100 kg ha-1 de gesso agrícola (6 x teor de argila em g kg-1, na camada de 0,20-0,40 m de profundidade). Para as culturas de verão foi utilizado o esquema de parcelas subsubdivididas, sendo as subsubparcelas constituídas por dois cultivares de arroz de terras altas... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: There is great interest to search alternatives to establish the no-tillage system in fields previously cultivated on conventional tillage or on pasture, with no lime previous incorporation, using superficial liming since the beginning of system, if don't have physical impediment to root growth. Thus, the phosphogypsum, that is more soluble and with high mobility, has been an alternative to correct the subsuperficial soil layer, in a short time, and can be used as a lime complementary product. Therefore, the objective of this work was to evaluate the effects of lime and phosphogypsum surface application during the establishment of no-tillage system, on the soil chemical characteristics, on the content of water-soluble cations, in the crop shoot, on the root growth, on the nutrition and yield of annual crops, in a dry winter region. The experiment was carried out during the agricultural years of 2002/03 and 2003/2004, in an experimental area located in Botucatu County, São Paulo State, Brazil (48º 23' W and 22º 1' S) on a Haplorthox, before used with conventional tillage system. A randomized complete block design, in split-plot scheme, and four replications was used. The plots were composed by four dolomite limestone levels (0; 1,100; 2,700; and 4,300 kg ha-1), with Neutralization Power = 84.3% and Reactivity = 84.5%, aiming raise the base saturation to 50%, 70%, and 90%, respectively. The subplots were composed by without and with phosphogypsum application (2,100 kg ha-1 = 6 x clay content (g kg-1) in 0.20-0.40 m depth layer). For the summer crops a split-split-plot scheme were used. The subsubplots were constituted by two upland rice cultivars ('Caiapó' and 'IAC 202'), on agricultural year of 2002/03, and two common bean cultivars ('Carioca' and 'Pérola'), on agricultural year of 2003/2004. In the winter season of 2003 and 2004, the black oat was grown in the area... (Complete abstract click electronic access below)
Doutor
34
Guimarães, Claudiney do Couto. "Ecoeficiência e sustentabilidade nutricional em povoamentos de eucaliptos no Bioma Pampa." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/13335.
Анотація:
The expansion of plantations with eucalyptus in Rio Grande do Sul state have been
consolidating and occupying areas that anteriorly had no silvicultural tradition in commercial
scale. The state occupies the sixth position in planted areas with eucalyptus and pinus in the
country and although a significant part of the cultivated area is established in the Pampa
Biome, few studies have been conducted to understand the behavior of eucalyptus in this
ecosystem. Therefore this study aimed to determine the efficiency of Eucalyptus dunnii,
Eucalyptus grandis, Eucalyptus benthamii, Eucalyptus saligna and hybrid of Eucalyptus
urophylla x Eucalyptus grandis (E. urograndis), at seven years of age, and provide elements
for nutrition and sustainable forestry management. To this it was estimated stock of total and
available nutrients in the soil up to 100 cm deep; it was determined the growth; biomass and
nutrients were quantified above and below ground for different species; were evaluated the
silvicultural and ecological implications of the removal of nutrients due to the different
biomass harvesting scenarios; and alternatives have been proposed for forestry management
and fertilization. The soil in the study area is classified as Ultisol. Samples were collected for
physical and chemical soil characterization. They were inventoried five sample units of 10 ha,
one for each species, to determine the growth variables. After the measurements distribution
was performed by diameter classes, which were determined three classes, the first class of 10
to 16 cm, the second 16.1 to 22 cm and the third class of 22.1 to 28 cm. To determine the tree
biomass in Mg ha-1, three trees were selected by diameter class being a tree at the lower limit,
a tree in the central limit and a tree at the upper limit of each class, totaling nine trees by
species. The trees were cut into compartments, sampling for determination of individual tree
biomass and nutrient content. The soils of the experimental areas had textural class 4 (clay
content < 20%), with significant differences between the chemical attributes in relation to
native field, highlighting the increased levels of P, K and S for the majority of species. The
highest annual mean increment and total volume were observed in E. saligna (61.10 m³ ha-1 to
427.55 m³ ha-1) followed by the E. grandis (54.84 m³ ha-1 m³ and 383.88 ha-1 E. urograndis
(54.25 m³ ha-1 and 379.78 m³ ha-1), E. benthamii (49.87 m³ ha-1 and 349.11 m³ ha-1) and E.
dunnii (45, 97 m³ ha-1 and 321.80 m³ ha-1). The highest biomass production was observed in
E. saligna, with 289.94 Mg ha-1; followed by E. urograndis with 231.66 Mg ha-1; E. grandis,
with 228.51 Mg ha-1; E. benthamii with 225.35 Mg ha-1 and E. dunnii with 205.62 Mg ha-1,
with allocation of biomass in stem wood of 74% E. urograndis and E. grandis, 70% for E.
saligna, 69% for E. benthamii and 67% for E. dunnii. The magnitude of biomass allocation
presented the same tendency among species – stem wood > root > branch > bark > leaf. The
highest concentration of N, P, K, S, B, Cu and Mn was observed in leave; stem wood showed
the highest concentration of Ca and Mg, and the root of the highest concentration of Fe and
Zn. The greatest amount of nutrients was observed in the stem wood, except for Ca and Mg, where larger quantities are allocated in the bark of the wood and the Fe that is allocated at the
root. In the litter there was the same distribution behavior for the nutrients (concentrations and
quantities) – Ca > N > Mg > K > S > P – Mn > Fe > B > Zn > Cu. The highest values for the
nutrients utilization efficiency were observed in E. grandis, E. saligna and E. dunnii for P; E.
urograndis and E. benthamii for Mg; E. saligna for S; E. grandis also presented the better
efficiency in N, K and Ca. The harvest only the stem wood provided a maintenance of soil
nutrients by other components of the biomass, greater than 50%, especially Ca and Mg with a
return of 82% and 72% respectively. The lowest nutrient removal rate according to the
intensity of biomass harvesting was verified in E. grandis. For the production number of
rotations, the P indicated a nutritional sustainability condition under all harvesting scenarios,
the N in the harvesting of the stem wood over bark and stem wood, Ca and Mg in the
harvesting of the stem wood, for all species; and the K was the element that presented the
greatest productivity risk limiting. The lower cost of nutritional replacement, among biomass
harvesting scenarios, was found in E. grandis followed by E. urograndis, E. dunnii, E.
saligna and E. benthamii.A expansão das plantações com eucalipto no estado do Rio Grande do Sul vem se consolidando e ocupando regiões que anteriormente não apresentavam tradição silvicultural em escala comercial. O estado ocupa a sexta posição em área plantada com eucalipto e pinus no país, e apesar de uma parte significativa da área cultivada estar estabelecida dentro do Bioma Pampa, poucos estudos foram realizados para compreender o comportamento do eucalipto nesse ecossistema. Diante disto, este estudo teve como objetivo determinar a eficiência de Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus benthamii, Eucalyptus saligna e híbrido Eucalyptus urophylla x Eucalyptus grandis (E. urograndis), aos sete anos de idade, e fornecer elementos para o manejo nutricional e silvicultural sustentável. Para isso estimou-se o estoque de nutrientes totais e disponíveis no solo até 100 cm de profundidade; determinou-se o crescimento e quantificou-se a biomassa e nutrientes acima e abaixo do solo para as diferentes espécies; avaliaram-se as implicações silviculturais e ecológicas decorrentes da remoção dos nutrientes em função dos diferentes cenários de colheita da biomassa; e foram propostas alternativas para o manejo silvicultural e da fertilização. O solo nas áreas do estudo é classificado como Argissolo Vermelho Distrófico típico. Amostras foram coletadas para a caracterização física e química do solo. Foram inventariadas cinco unidades amostrais de 10 ha cada, sendo uma unidade para cada espécie, para se determinar as variáveis de crescimento. Após as medições realizou-se a distribuição por classe diamétrica, onde se determinou três classes, sendo a primeira classe de 10 a 16 cm, a segunda de 16,1 a 22 cm e a terceira classe de 22,1 a 28 cm. Para a determinação da biomassa arbórea em Mg ha-1, foram selecionadas três árvores por classe diamétrica sendo uma árvore no limite inferior, uma árvore no limite central e uma árvore no limite superior de cada classe, totalizando nove árvores por espécie. As árvores foram seccionadas em compartimentos, retirado amostras para determinação da biomassa arbórea individual e dos teores dos nutrientes. Os solos apresentaram classe textural 4 (teor de argila < 20%), com diferenças significativas entre os atributos químicos em relação ao campo nativo, destacando-se o aumento dos teores de P, K e S para a maioria da espécies. O maior incremento médio anual e volume total foram observados para E. saligna (61,10 m³ ha-1 e 427,55 m³ ha-1) seguido por E. grandis (54,84 m³ ha-1 e 383,88 m³ ha-1), E. urograndis (54,25 m³ ha-1 e 379,78 m³ ha-1), E. benthamii (49,87 m³ ha-1 e 349,11 m³ ha-1) e E. dunnii (45,97 m³ ha-1 e 321,80 m³ ha-1). A maior produção de biomassa foi observada para E. saligna, com 289,94 Mg ha-1; seguido pelo E. urograndis, com 231,66 Mg ha-1; E. grandis, com 228,51 Mg ha-1; E. benthamii, com 225,35 Mg ha-1 e pelo E. dunnii com 205,62 Mg ha-1, com alocação da biomassa na madeira do tronco em torno de 70% para todas as espécies. A magnitude de alocação da biomassa apresentou o mesmo comportamento entre as espécies – madeira do tronco > raiz > galho > casca > folha. A maior concentração de N, P, K, S, B, Cu e Mn foi observada na folha; a casca da madeira apresentou a maior concentração de Ca e Mg, e a raiz a maior concentração de Fe e Zn. A maior quantidade dos nutrientes foi observada na madeira do tronco, exceto para o Ca e Mg, onde as maiores quantidades estão alocadas na casca da madeira e para o Fe que está alocado na raiz. Na serapilheira verificou-se o mesmo comportamento de distribuição para os nutrientes (teores e quantidades) – Ca > N > Mg > K > S > P - Mn > Fe > B > Zn > Cu. Os maiores valores para a eficiência de utilização de nutrientes foram observados em E. grandis, E. dunnii e E. saligna para P; E. urograndis e E. benthamii para o Mg; e E. saligna para S, destacando-se também a melhor eficiência em N, K e Ca em E. grandis. A colheita apenas da madeira do tronco proporcionou uma manutenção de nutrientes no solo pelos demais componentes da biomassa, acima de 50%, especialmente para Ca e Mg com uma devolução de 82 e 72% respectivamente. A menor taxa de remoção de nutrientes de acordo com intensidade da colheita da biomassa foi verificada para E. grandis. Para o número de rotações de produção, o P indicou uma condição de sustentabilidade nutricional, sob todos os cenários de colheita, o N sob a colheita da madeira do tronco com casca e madeira do tronco, e o Ca e Mg sob a colheita da madeira do tronco, para todas as espécies; e o K foi o elemento que apresentou o maior risco a limitação da produtividade. O menor custo de reposição nutricional, entre os cenários de colheita da biomassa, foi verificado para E. grandis seguido pelo E. urograndis, E. dunnii, E. saligna e E. benthamii.
35
Cera, Rull Andreu. "The ecological significance of nutritional strategies in gypsum plant communities." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673600.
Анотація:
Gypsophile species are edaphic endemics of gypsum soils, and they are considered specialists of this stressful substrate. Gypsum endemics from different families and regions of the world tend to show a unique leaf elemental composition, similar to the chemical characteristics of gypsum soils. However, the ecological significance of their unique foliar composition remains unknown. The factors underlying the ecological amplitude of gypsophiles remain also poorly studied. The main literature is based on the distribution of gypsophiles linked to gypsum soils in drylands, although some studies suggest a broader physiological amplitude depending on soil type, and a positive influence of disturbance. Therefore, I have assumed that gypsophiles have evolved in disturbed drylands with gypsum soils. In order to adapt to this combination of factors, I hypothesised that gypsophiles have become soil specialists with high capacity of nutrient uptake to be more competitive than other species in gypsum soils. To test this, we conducted a germination trial and a common garden experiment to analyse the ecological restriction of gypsophiles to different substrates, and to analyse the effect of different substrates on the whole-plant elemental composition of plants with contrasting affinity for gypsum soils. In the field, we studied the assemblage of plant communities under different grazing intensities on high gypsum soils, and whether the assembly of plant communities is mediated by any trait related to gypsum specialisation or herbivory resistance. Next, a browsing simulation was conducted to assess individual plant responses in calcic and gypsum pots. In addition, the variation of foliar and rhizospheric soil nutrient contents, and AM fungal colonisation were analysed throughout a year in the field to study the nutrient acquisition strategies of gypsophiles. The results obtained in this PhD thesis show that the fundamental niche of gypsophiles is not only explained by edaphic factors unique to gypsum soils, but seems to be related to alkaline soils with high calcium availability. When analysed under herbivory pressure, species with high gypsum affinity and increased foliar S content (i.e. gypsophiles) were more likely to assemble than other species. These gypsophiles were foliar accumulators of gypsum excess elements, even in calcic pots. They also seem to be adapted to P-scarcity by being less dependent on AMF symbiosis, and adjusting their acquisition strategies to nutrient pulses. Therefore, it seems that gypsophiles are specialists of gypsum soils to be more competitive in disturbed drylands through a unique nutritional strategy.Les plantes gipsòfiles són endemismes edàfics del guixos, i són considerades especialistes d’aquest sòl estressant. Endemismes del guix de diferents famílies i regions del món tendeixen a mostrar una composició elemental foliar única, similar a les característiques químiques dels sòls guixencs. No obstant això, el significat ecològic de la seva composició foliar continua sent desconegut. Els factors que subjuguen l’amplitud ecològica de les gipsòfiles segueixen sent també poc estudiats. La majoria de la literatura es basa en una distribució lligada als sòls guixencs de les zones àrides, encara que alguns estudis suggereixen una amplitud fisiològica més àmplia segons el tipus de sòl, i una influència positiva de les pertorbacions. Per això, he assumit que les gipsòfiles han evolucionat en terres seques pertorbades amb sòls guixencs. Per adaptar-se a aquesta combinació de factors, he plantejat la hipòtesi que s’han convertit en especialistes edàfics amb alta capacitat d’absorció de nutrients per a ser més competitives que altres espècies en sòls de guix. Per comprovar-ho, vam dur a terme un experiment de germinació i un de cultiu per a analitzar la seva restricció ecològica en funció del tipus de sòl, i per analitzar la composició elemental de tota la planta. En el camp, vam estudiar l’assemblatge de les comunitats vegetals en sòls guixencs en diferents intensitats de pasturatge, i si l’assemblatge d’aquestes comunitats està mediat per algun tret relacionat amb l’especialització pels guixos o la resistència cap als herbívors. A continuació, vam realitzar una simulació de brosteig per a avaluar la resposta individual de les plantes en tests amb guix o sòl calcari. A més, vam analitzar durant un any la variació del contingut nutricional de les fulles, arrels i sòl rizosfèric, i la colonització dels fongs micorízics arbusculars, per estudiar les estratègies d’adquisició de les gipsòfiles en el camp. En conjunt, els resultats obtinguts en aquesta tesi doctoral demostren que el nínxol fonamental de les gipsòfiles no sols s’explica per factors singulars dels sòl guixencs, sinó més aviat per sòls alcalins amb alt contingut de calci. I quan afegim la pressió herbívora, les espècies amb alta afinitat pel guix i alt contingut de sofre foliar (és a dir, gipsòfiles) tenen més probabilitat d’assemblar-se que altres espècies. Hem comprovat també que aquestes gipsòfiles són acumuladores foliars dels elements en excés dels guixos, fins i tot quan creixen en tests amb sòl calcari. I que les gipsòfiles semblen estar adaptades a l’escassetat de fòsfor sent menys dependents de la simbiosi amb AMF, i probablement ajustant les estratègies d’adquisició als polsos nutricionals del sòl. Per tant, sembla que les gipsòfiles s’han convertit en especialistes dels sòls guixencs per a ser més competitives en terres seques pertorbades amb sòls guixencs a través d’una estratègia nutricional singular.
36
Terrill, Thomas Howard. "Effects of soil moisture and al-nitrilotriacetate on yeild chemical composition and digestibility of ryegrass (Lolium multiflorum, L.) by meadow voles." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/53088.
Анотація:
Flooding effects mineral composition of pasture grasses, but little is known concerning effects on mineral metabolism and fiber digestibility in animals. Experiments were conducted to investigate effects of flooding and Al-nitrilo-triacetate (Al-NTA) on growth, chemical composition and digestibility of annual ryegrass (Lolium multiflorum, L.). Ryegrass was grown in a greenhouse experiment on Bucks silt loam soil with two soil moisture levels (flooding and 80% field capacity) and two Al rates (0 and 135 mg/kg) as Al-NTA.
Flooding increased Al, Fe, Cu, Ca and fiber and decreased dry matter yield, Mg, K and Zn concentrations. Treatment with 135 mg/kg Al had no effect on Al in plants, but decreased Ca and P concentrations.
Two digestion trials were conducted with meadow voles (Microtus pennsylvanicus) fed forage harvested from the greenhouse experiment. Voles were housed in stainless steel metabolism cages for total collections of feed and feces. A 2-day preliminary, during which voles were fed 100% ryegrass, preceded a 3-day collection period. At the end of the collection period, a blood sample was taken from the animals.
Forage grown under flooding increased apparent absorption of Al, and Ca concentration in urine samples. Apparent absorption of Mg and serum Mg were decreased, and dry matter digestibility tended to decrease.
Grazing forages produced under flooded conditions would increase potential for outbreaks of grass tetany in animals due to reduced Mg intake and absorption. Altered Mg and Ca metabolism appeared related to Al ingestion. Lowered animal performance could result from reduced DM digestibility.Master of Science
37
Shange, Philisiwe Lawrancia. "Nutritional status of geologically different vineyards in Helderberg." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2603.
Анотація:
Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: Little scientific information regarding the effect of different geological parent materials on grapevine performance is currently available in South Africa. This aspect is of special significance for the Helderberg area, where parent material may change from granite to shale over a short distance. This results in shale- as well as granite-derived soils often occurring within the same vineyard. The objectives of this study were to (i) quantify the nutritional status and other soil properties of different parent materials (shale and granite) and overlying soils (ii) investigate the impact of geological differences in the soil on the vine nutritional status and certain vine parameters. This study was done over two seasons (2006/2007 and 2007/2008). Two Sauvignon blanc and two Cabernet Sauvignon vineyard blocks were selected at two different localities for each cultivar in the Helderberg area, South Africa. Shale- and granitederived soils were identified within each block. Kaolinite was the dominant mineral, whereas quartz and feldspar were sub-dominant. Traces of mica were also present in some shale- and granite-derived soils. Granite- contained significantly higher contents of coarse sand than shale-derived soils, whilst the opposite occurred in terms of fine sand. These differences affected the water holding capacity, in general making it higher in shale- than granite-derived soils. Shale-derived soils had higher concentrations of total K but granite-derived soils had a higher ability to release K as they contained higher concentrations of soluble K. The Q/I parameters, potential buffering capacity of K (PBCK) and equilibrium activity ratio of K (ARK) showed no consistent responses to geological differences. Potassium concentrations were higher in the leaf blades (obtained before harvest in 2007) from Sauvignon blanc grapevines on granite- than on shale-derived soils. Potassium concentrations in the Cabernet Sauvignon juice (obtained in 2007) tended higher in juice from granite- than from shale-derived soils. In 2008, K concentrations tended higher in juice from shale- than from granite-derived soils for both cultivars. The pH of the Sauvignon blanc juice (obtained in 2008) tended higher in juice from shale-than from granite-derived soils, thus corresponding with the K concentrations in the juice in this season. Nitrogen concentrations were higher in Cabernet Sauvignon juice (obtained in 2007) and Sauvignon blanc juice (obtained in 2008) from shalethan from granite-derived soils. In terms of vine water status, vines on granite-derived soils appeared more stressed than those on shale-derived soils in both seasons at one of the vineyards. In these Sauvignon blanc and Cabernet Sauvignon vineyards, the K nutritional status was not affected by geology in a consistent manner but there were some noticeable tendencies for a specific cultivar during certain seasons. On account of vines being planted on shale- and granite-derived soils within the same block, soil preparation was done similarly for both soils, and they were exposed to similar irrigation schedules, canopy management strategies and climatic conditions. Therefore, there is a high probability that all these practices may have negated the effect of geology on the K status of soils and especially on juice K concentration at the time of harvest. It was clear that seasonal differences and fertilisation affected the nutritional status of the vines more than geology.
AFRIKAANSE OPSOMMING: In Suid-Afrika is daar tans min wetenskaplike inligting oor die effek van verskillende geologiese moedermateriale op die prestasie van wingerd beskikbaar. Hierdie aspek is veral van belang in die Helderberg-area, waar moedermateriaal oor ‘n baie kort afstand van graniet na skalie kan wissel. Dit lei daartoe dat skalie-, sowel as granietgronde, dikwels binne dieselfde wingerd voorkom. Die doelwitte van die studie was om: (i) die voedingstatus en ander grondkundige eienskappe van die verskillende moedermateriale (skalie en graniet) en oorliggende gronde te kwantifiseer (ii) die impak van geologiese verskille in die grond op wingerd se voedingstatus en sekere wingerdkundige parameters, te ondersoek. Hierdie studie is oor twee seisoene (2006/2007 en 2007/2008) gedoen. Twee Sauvignon blanc en twee Cabernet Sauvignon wingerdblokke is geselekteer by twee verskillende lokaliteite vir elke kultivar in die Helderbergarea, Suid-Afrika. Beide skalie- en granietgrond is binne elke blok geïdentifiseer. Kaoliniet was die dominante mineraal, met kwarts en veldspaat sub-dominant, terwyl spore van mika ook in beide skalie- en granietgronde gevind is. Granietgronde het betekenisvol hoër hoeveelhede growwe sand bevat, terwyl skaliegronde meer fyn sand bevat het. Hierdie verskille het ‘n effek op waterhouvermoë gehad en daartoe gelei dat waterinhoude oor die algemeen hoër was vir skaliegronde. Skaliegronde het groter hoeveelhede totale K bevat, maar granietgronde se vermoë om K vry te stel was hoër, omdat hulle ‘n hoër konsentrasie oplosbare K bevat het. Die Q/I parameters, potensiële buffervermoë vir K (PBCK) en ewewig aktiwiteitsverhouding vir K (ARK), is nie op ‘n konsekwente wyse deur geologiese verskille beïnvloed nie. Vir die Sauvignon blanc wingerde was kalium konsentrasies in blaarskywe (gemonster voor oes in 2007) hoër vir graniet- as vir skaliegronde. Kalium konsentrasies in die sap vanaf Cabernet Sauvignon (gemonster in 2007) het hoër geneig vir granietgronde. In 2008 het die kalium konsentrasies, vir beide kultivars, hoër geneig in sap vanaf skaliegronde. Gedurende dié seisoen het die pH van sap ook hoër geneig vir Sauvignon blanc vanaf skaliegronde, wat dus ooreenstem met die K inhoud van die sap. Stikstof konsentrasies was hoër in sap vanaf skaliegronde vir Cabernet Sauvignon (2007) en vir Sauvignon blanc (2008). In terme van die wingerde se waterstatus, het stokke op die granietgrond, by een van die lokaliteite, geneig om gedurende beide seisoene onder groter stremming te wees op graniet as op skaliegrond. In hierdie Sauvignon blanc en Cabernet Sauvignon wingerde, is K voedingstatus nie op ‘n konsekwente wyse deur geologie geaffekteer nie, maar gedurende sommige seisoene was daar wel duidelike tendense vir ‘n spesifieke kultivar. Omdat die stokke binne dieselfde blok op skalie- en graniet gronde geplant is, was grondvoorbereiding eenders vir die twee grondtipes terwyl besproeiingskedule, lowerbestuur en klimaatstoestande ook identies was. Daar is dus ‘n hoë waarskynlikheid dat al hierdie faktore daartoe kon bygedra het dat die effek van geologie op die K status van van gronde versluier is, veral die effek op die K inhoud van sap teen oestyd. Dit was duidelik dat seisoenale klimaatsverskile en bemestingspraktyke ’n groter effek as geologie op die voedingstatus van die wingerd gehad het.
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Beulch, Lien da Silveira. "BIOMASSA E NUTRIENTES EM UM POVOAMENTO DE Eucalyptus saligna Smith SUBMETIDO AO PRIMEIRO DESBASTE." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/8720.
Анотація:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEucalyptus is one of the most cultivated species in Brazil due to its fast increment and adaptation to the various types of soils and its characteristics related to the climate. In the county of Rio Grande do Sul (RS), the area of forestry planting has expanded taking over areas where previously were used for agriculture and cattle. Therefore it has been made necessary the development of researches that aim to fully establish the cultivation of Eucalyptus saligna in a sustainable way. The present study had the objective to quantify the biomass and the storage of nutrients of an area planted with Eucalyptus saligna which had its first thinning in São Francisco de Assis RS. The data was collected in a plot which is 4 years old, situated in an area which has low fertility soil, in the farm Estancia das Oliveiras, which belongs to the company Stora Enso. In total it was selected nine trees to sample. The destructive sampling consisted of the individualization of compartments of the biomass presented over the soil (leaves, twigs, bark and wood). The collection of samples aimed to determine the quantity of dried material in the different compartments of Eucalyptus saligna. The production of biomass in the clear- cutting was 88.81 Mg ha-1, showing the following percentage of distribution: 76.8% in the wood, 9.3% in the bark, 7.9% in the twigs and 6.0% in the leaves. The capacity of storage of elements by the biomass presented the following decreased order of accumulation of macronutrients Ca > K > N > Mg > P > S and Mn > Fe > B > Zn > Cu of micronutrients. In the occasion of the thinning of 40% of the plot, the production of biomass was 35.52 Mg ha-1. When it was solely done the collection of the commercial wood and bark (d≥ 8 cm), the biomass left in the field would contribute with 60.2% of the macronutrients and 59.9% of the micronutrients. Removing only the commercial wood, the percentage of nutrients left in the field raises to 80.5% of macronutrients and 88.4% of micronutrients. Independently on the chosen system, the most limiting nutrient for the next rotations would be Potassium. In ecological terms, the process that would least export nutrients from the system would be the one in which you would only collect the commercial wood, living the other components such as leaves, twigs and bark in the soil as a forestry waste.
O eucalipto é uma das espécies florestais mais cultivadas no Brasil devido ao seu rápido crescimento e adaptação a vários tipos de solos e características climáticas. No Rio Grande do Sul, houve aumento na área de abrangência dos plantios florestais, passando a ocupar regiões anteriormente predominadas pela agricultura e pecuária, tornando necessária a realização de pesquisas que visem à garantia do pleno estabelecimento dos plantios de Eucalyptus de forma sustentável. O presente estudo teve como objetivo quantificar a biomassa e o estoque de nutrientes em um povoamento de Eucalyptus saligna submetidos ao primeiro desbaste no município de São Francisco de Assis-RS. Os dados foram coletados em um talhão de quatro anos de idade, estabelecido em solo de baixa fertilidade na Fazenda Estância das Oliveiras, pertencente a Empresa Florestal Stora Enso. Foram selecionas no total nove árvores para comporem as amostras. A amostragem destrutiva consistiu na individualização dos compartimentos da biomassa acima do solo (folhas, galhos, casca e madeira). A coleta das amostras teve como objetivo a determinação da matéria seca nos diferentes componentes do Eucalyptus saligna. A produção de biomassa aos quatro anos foi de 88,81 Mg ha-1, apresentando o seguinte percentual de distribuição: 76,8% na madeira, 9,3% na casca, 7,9% nos galhos e 6,0% nas folhas. A magnitude de armazenamento dos elementos na biomassa total apresentou a seguinte ordem decrescente de acumulo para macronutrientes: Ca > K > N > Mg > P > S e Mn > Fe > B > Zn > Cu para os micronutrientes. Na ocasião do desbaste de 40% do povoamento a produção de biomassa foi de 35,52 Mg ha-1. Quando realizada apenas a colheita da madeira comercial e casca comercial (d≥ 8 cm) a biomassa deixada no campo contribuiria com 60,2% dos macronutrientes e 59,9% dos micronutrientes. Removendo apenas a madeira comercial, a porcentagem de nutrientes deixados no campo subiria para 80,5% de macronutrientes e 88,4% de micronutrientes. Independente da intensidade de colheita aplicada, o nutriente mais limitante para as futuras rotações seria o potássio. Em termos ecológicos e silviculturais, o processo que menos exportaria nutrientes do sistema seria aquele em que se colheria apenas a madeira comercial, deixando os demais componentes (folhas, ponteiros, galhos, casca) no sítio, como resíduo florestal.
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Magnusson, Margareta. "Soil pH and nutrient uptake in cauliflower (Brassica oleracea L. var botrytis) and Broccoli (Brassica oleracea L. var. italica) in northern Sweden : multielement studies by means of plant and soil analyses /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5750-5.pdf.
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Salvador, Simone Martini. "QUANTIFICAÇÃO DA BIOMASSA E NUTRIENTES EM PLANTIOS DE Eucalyptus urograndis EM SOLOS DISTINTOS." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/8769.
Анотація:
Conselho Nacional de Desenvolvimento Científico e TecnológicoThis study aimed to obtain information in order to contribute to the nutritional management of Eucalyptus urograndis, based on nutritional characterization, in two different soil types, for the region of Telêmaco Borba - PR. Delimited by 4 parcels located on each floor, making the measurement of all diameters and selection of trees to be felled. The trees were cut at soil level, and the fractionated components: leaves, branch, bark, stem wood, root and ferrule, by collecting a representative sample of each fraction as well as weighed to obtain biomass. To collect the litter were collected 10 samples in each parcels. All the vegetation contained within the floor area of each felled tree (7,5 m2), was regarded as understory which is collected throughout the biomass above and below ground. All biomass samples, understory and litter were sent to the Laboratório, where they were dried at 700C, and after were sent for chemical analysis to determine the macro and micronutrients. The tree biomass total found in the present study was 257,99 Mg ha-1 at a relative contribution of 1,01%; 2,69%; 5,23%; 74,38%; 16,69% F, G, C, M, R, respectively, to the ground soil A. To the soil B in total tree biomass was found 301,21 Mg ha-1 with a compartment relative contribution 1,33% F; 3,80% G; 8,33% C; 74,28% M and 12,27 % of R. The total stock of macro and micronutrients was 1,64 Mg ha-1 for the soil A, with most of the nutrients are found in greater amounts in the compartment wood, except the skin Ca and Fe in the root compartment. For the soil B, the total stock of nutrients was 2,39 Mg ha-1 and most of the nutrients also presented as a higher incidence of compartment wood, except Ca and Mg that are in the bark and B and Fe that are in the compartment roots. The litter presented a biomass in sandy soil 17,35 Mg ha-1, and a total stock of nutrient 335,73 kg ha-1, while for the soil B, biomass was 20,93 kg ha-1 and the total stock of nutrients was 456,76 kg ha-1, and the full magnitude of the amount of macronutrients in litter was N > Ca > Mg > K > S > P, in both soil types. The total biomass found in the understory was 1,08 Mg ha-1 and the total stock of nutrients was 37,96 kg ha-1 for soil A, however, to the soil B, the total biomass was 0,88 Mg ha-1 and the total stock of nutrients was 36,94 kg ha-1, and in both types of soil, the greatest relative contribution of N was 50% for soil A and 53% for the soil B. Among the simulations, the first harvest system the total nutrient exported from the site would be 48% and 57% for sandy and clay soils, respectively, decreasing to 32% in sandy soil and 28% in clay soil to second harvest system and reaching only 20% in sandy soil and 15% in the third clay soil harvest system, causing a reduction of 28% and 42%, respectively examined for each type of soil, thus evident that the harvest system occurs only where the withdrawal of the site is the most suitable wood, which is more sustainable for the site and which could ensure the best nutritional conditions for the next rotation. For the production of all components of the biomass P and Mg elements, the macronutrients are most effectively used in both soil types analyzed, and the coefficient of use for the organic component wood in the following order: P > Mg > S > Ca > N > K for both types of ground studied.
O presente trabalho teve por objetivo obter informações a fim de contribuir para o manejo nutricional da espécie Eucalyptus urograndis, com base na caracterização nutricional, em dois diferentes tipos de solo, para a região de Telêmaco Borba PR. Delimitou-se 4 parcelas localizadas em cada solo, realizando a medição de todos os diâmetros e escolha das árvores para serem abatidas. As árvores foram seccionadas ao nível do solo e fracionadas nos componentes: folhas, galhos, casca, madeira do tronco, raiz e ponteira, coletando-se uma amostra representativa de cada fração, bem como a pesagem para determinação da biomassa. Para a coleta da serapilheira acumulada foram coletadas 10 amostras em cada parcela. Toda a vegetação, contida dentro da área útil de cada árvore abatida (7,5 m2), foi considerada como sub-bosque onde coletou-se toda a biomassa acima e abaixo do solo. Todas as amostras de biomassa, sub bosque e serapilheira foram encaminhadas para o Laboratório, onde foram secas a 700C, e após foram encaminhadas para análise química para determinação dos macro e micronutrientes. A biomassa arbórea total encontrada para o presente estudo foi de 257,99 Mg ha-1, com uma contribuição relativa de 1,01 %; 2,69 %; 5,23 %; 74,38 %; 16,69 % de F, G, C, M, R, respectivamente, para o solo A. No solo B a biomassa arbórea total encontrada foi de 301,21 Mg ha-1, com contribuição relativa por compartimento de 1,33 % de F; 3,80 % de G; 8,33 % de C; 74,28 % de M e 12, 27 % de R. O estoque total de macro e micronutrientes foi de 1,64 Mg ha-1, para o solo A, sendo que a maioria dos nutrientes encontram-se em maiores quantidades no compartimento madeira, exceto Ca na casca e Fe no compartimento raiz. Para o solo B, o estoque total de nutrientes foi de 2,39 Mg ha-1 e a maioria dos nutrientes também apresentou como maior compartimento de ocorrência a madeira, exceto Ca e Mg que estão nas casca e B e Fe que estão no compartimento raízes. A serapilheira acumulada apresentou uma biomassa em solo arenoso de 17,35 Mg ha-1, e um estoque total de nutrientes de 335,73 kg ha-1, já para o solo B, a biomassa foi de 20,93 kg ha-1 e o estoque total de nutrientes foi de 456,76 kg ha-1, e a magnitude total da quantidade de macronutrientes na serapilheira acumulada foi de N > Ca > Mg > K > S > P, em ambos os tipos de solo. A biomassa total encontrada no sub-bosque foi de 1,08 Mg ha-1 e o estoque total de nutrientes foi de 37,96 kg ha-1 para o solo A, contudo, para o solo B, a biomassa total foi de 0,88 Mg ha-1 e o estoque total de nutrientes foi de 36,94 kg ha-1, sendo que em ambos os tipos de solo a maior contribuição relativa foi de N com 50% para o solo A e 53% para o solo B. Dentre as simulações realizadas, no primeiro sistema de colheita o total de nutrientes exportado do sítio seria de 48% e 57% para o solo arenoso e argiloso, respectivamente, reduzindo para 32% no solo arenoso e 28% no solo argiloso para o segundo sistema de colheita e chegando a apenas 20% no solo arenoso e 15% no solo argiloso no terceiro sistema de colheita, ocorrendo uma redução de 28% e 42%, respectivamente para cada tipo de solo analisado, ficando assim evidente que o sistema de colheita onde ocorre apenas a retirada da madeira do sítio é o mais indicado, sendo este o mais sustentável para o sítio e o que poderá garantir as melhores condições nutricionais para as próximas rotações. Para a produção de todos os componentes da biomassa os elementos P e Mg, são os macronutrientes mais eficientemente utilizados em ambos os tipos de solo analisados, e o coeficiente de utilização biológica para o componente madeira descreu na seguinte ordem: P > Mg > S > Ca > N > K para ambos os tipos de solo estudados.
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Sadeghzadeh, Behzad. "Mapping of chromosome regions associated with seed zinc accumulation in barley." University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0204.
Анотація:
[Truncated abstract] Zinc deficiency in crops is the most widespread micronutrient deficiency, with about 50% of the cereal-growing areas worldwide containing low levels of plant-available Zn. Zinc plays multiple key roles in different metabolic and physiological processes; its deficiency in crops reduces not only grain yield, but also the nutritional quality of grains. Insufficient micronutrient intake, particularly Zn and Fe, afflicts over 3 billion people in the world, mainly in developing countries. Increasing the amount of Zn in food crops can contribute to improving the Zn status of people. Furthermore, Zn-dense seeds have agronomic benefits, resulting in greater seedling vigour, bigger root system and higher crop yield when sowed to soils with low plant-available Zn. Enhancing nutrient content and nutritional quality of crops for human nutrition is a global challenge currently, but it was mostly ignored during the breeding process in the past. There is a significant genotypic variation for seed Zn accumulation in several crops (including barley) which could be exploited in the breeding programs to produce genotypes with higher seed Zn concentration and content. However, the progress in Zn efficiency until now has mainly relied on conventional plant breeding approaches that have had limited success. Therefore, reliable alternative methods are required. Enhancing mineral nutrition through plant biotechnology may be a sustainable and beneficial approach in developing Zn-dense seeds in the staple crops. ... This DNA band was sequenced and converted into a simple sequence-specific PCR-based marker, which was designated as SZnR1 (seed Zn-regulator1). The developed marker is very easy to score, is inexpensive to run and amenable for a large number of plant samples. The successful development of SZnR1 molecular marker linked to chromosome region associated with seed Zn concentration and content using MFLP in this study illustrates the advantage of this technique over some other DNA fingerprinting methods used for identification of molecular markers for marker-assisted selection (MAS). In conclusion, the greater Zn efficiency of Sahara over Clipper under sufficient Zn supply may be attributed to its higher uptake of Zn. It appears that soil-based pot experiments under controlled condition may offer potential improvements over field experiments in screening for seed Zn accumulation. Shoot and seed Zn concentration and content can be used to diagnose the Zn statues of barley genotypes, and may be a useful selection criterion for Zn efficiency in large populations like doubled-haploid populations aimed at developing molecular markers for Zn efficiency. Identified QTLs influencing seed Zn concentration were repeatable in the field and glasshouse conditions, suggesting their robustness across environments as well as their value in marker-assisted selection. The developed PCR-based marker SZnR1 and other molecular markers associated with the QTLs on the short and long arms of chromosome 2H have the potential to be used for marker-assisted selection in breeding for Zn-dense seed in barley.
42
Herbert, Nick. "The mineral nutrition of heather on calcareous soil." Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285878.
Анотація:
Ericaceous plants grow preferentially on soils with a low pH, and generally perform poorly in areas with high pH calcareous soils. The reasons for the calcifuge behaviour of species of one genus, Erica, was studied in a calcareous rendzina collected from the South Downs, with a view to identifying physiological characteristics which could be used to select for improved lime-tolerance in the Ericaceae. Varieties of E. carnea and E. x darleyensis were shown to be relatively resistant to chalk-soil compared with varieties of E. vagans. In soil-based screening experiments, E. vagans 'Lyonesse' and 'Mrs D. F. Maxwell' rapidly developed severe foliar chlorosis, or lime-induced chlorosis, and their growth in soil was depressed by up to 7-fold compared with plants in an acid (pH 4) peat compost. E. carnea and E. x darleyensis varieties were resistant to chlorosis and remained green in chalk soil. The addition of nutrients (NPK and trace elements) increased the growth of the lime-resistant varieties in both peat and chalk soil. In nutrient solution, the source of nitrogen (nitrate or ammonium ions) had little effect on the growth of either lime-resistant or lime-sensitive varieties, although some varieties performed better when a component of the N was in the form of N03'. In an Fe-free nutrient solution, 1 mM NaHCO3 markedly reduced the root and shoot growth of both lime-tolerant and sensitive varieties. The clear differences between lime-resistant and lime-sensitive varieties found in soil experiments were not apparent with NaHCO3 in solution culture indicating that low concentrations of bicarbonate in nutrient solution may not be an appropriate method of screening for improved lime-tolerance in Erica. Bicarbonate and high pH in nutrient solution depressed the uptake of the radioisotopes 59Fe and 86Rb in both lime-resistant and lime-sensitive cultivars. Iron deficiency, induced by withholding Fe in nutrient solution, resulted in an elevated rate of root Fe(III)EDTA (ethylenediaminetetraacetic acid) reduction compared with Fesufficient plants. The maximum induced Fe(III)EDTA reduction rate (Vn,. ) of limeresistant cultivars (0.96-0.107 pmol. g"' FWT. h'') was lower than that of lime-sensitive varieties (0.125-0.404 tmol. g' FWT. h-1), suggesting that roots of lime-sensitive varieties have a greater capacity for Fe absorption than lime-tolerant varieties. Spraying or watering with Fe chelate (FeEDDHA - ethylenediamine di(ohydroxyphenylacetic acid)) remedied chlorosis in the lime-sensitive varieties and increased leaf chlorophyll by up to six fold and whole plant biomass by up to two fold. Chlorosis was associated with a reduced concentration of o-phenanthroline-extractable ('active') Fe, and a high concentration of total Fe, compared with green tissue. It is concluded that in chalk soil, lime-induced chlorosis, caused by the immobilisation of Fe in the shoot and a reduction in 'physiologically active' Fe in the leaf tissue, characterises lime-sensitive heather varieties. Resistance to chalk soil in Erica appears not to be related to root physiology. Rather the ability to transport and distribute Fe within the shoot under calcareous conditions is a major factor contributing to limeresistance in heathers.
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Souza, Huan Pablo de. "CARACTERIZAÇÃO NUTRICIONAL DO Eucalyptus benthamii Maiden & Cambage EM ÁREA DE PRODUÇÃO DE SEMENTES." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/8767.
Анотація:
Eucalyptus is the most planted forest genus in Brazil and worldwide. The eucalyptus plantations are established in various environments, and in the state of Rio Grande do Sul, new plantations are being established in the Pampa biome region. Therefore, there is need to use appropriate and correct genetic material nutritional management of stands. This study aimed to characterize nutritionally one Seed Production Area (APS) Eucalyptus benthamii, to six years in the city of São Francisco de Assis - RS, on the farm Estância das Oliveiras, owned by Stora Enso Florestal RS company. For the study, nine trees were harvested in three diameter classes, where samples of biomass were obtained above and below ground (leaves, branches, wood, bark, fruits and root) with subsequent determination of the dry mass and the concentration of macro and micronutrients. The total biomass in Seed Production Area was 47,59 Mg ha-1, with the following percentage of biomass: 62,14% in the wood, 10,19% in the branches, 8,26% in the bark, the leaves has 6,25%, 0,05% in the fruits and 13.11% in the roots. The stock of elements in the total biomass accumulation showed the following order of macronutrients: N > K > Ca > Mg > P > S and micronutrients to the order of distribution was as follows: Fe > Mn > Zn > B > Cu. The macronutrient concentrations in the biomass followed the sequence: wood > roots > leaves > branches > bark > fruit. For micronutrient concentrations follow the order: root > wood > branches > leaves > bark > fruit. The export of nutrients by the intensity of harvest of biomass components had the following distribution trend in the collection scenario 1 (30% removal leaves, twigs + 30% + 100% fruit): Mn> N> Cu> K> Mg> S> B> Ca> P> Zn> Fe Considering the scenario 2 (50% removal leaves, twigs + 50% + 100% fruit) harvesting the export of nutrients had the following distribution: Mn > N> Cu> K> Ca> Mg> S> B> P> Zn> Fe. For the scenario of harvest 3 (removal of 100% + 100% leaves and branches all fruit) export of nutrients presented following distribution: Mn> N> Cu> B> Mg> K> Ca> S> P> Zn> FeO Eucalyptus é o gênero florestal mais plantado no Brasil e no mundo. Os povoamentos de eucalipto estão estabelecidos nos mais variados ambientes, sendo que, no estado do Rio Grande do Sul, novas plantações estão sendo estabelecidas na região do bioma Pampa. Para tanto, há necessidade de utilização de material genético adaptado e correto manejo nutricional dos povoamentos. O presente estudo teve por objetivo caracterizar nutricionalmente uma Área de Produção de Sementes (APS) de Eucalyptus benthamii, aos seis anos, no município de São Francisco de Assis RS, na fazenda Estância das Oliveiras, pertencente à empresa StoraEnso Florestal RS. Para realizar o estudo, foram abatidas nove árvores, em três classes de diâmetro, onde as amostras da biomassa foram obtidas acima e abaixo do solo (folhas, galhos, madeira do tronco, casca do tronco, frutos e raiz), com posterior determinação da massa seca e a concentração dos macro e micronutrientes. A produção de biomassa total na Área de Produção de Sementes foi de 47,59 Mg ha-1, com a seguinte distribuição de biomassa: 62,14% na madeira do tronco, 10,19% nos galhos, 8,25% na casca do tronco, 6,26% nas folhas, 0,05% nos frutos e 13,11% nas raízes. O estoque dos elementos na biomassa total apresentou a seguinte ordem de acúmulo para macronutrientes: N > K > Ca > Mg > P > S e para os micronutrientes a ordem de distribuição foi a seguinte: Fe > Mn > Zn > B > Cu. A concentração dos macronutrientes na biomassa apresentou a seguinte ordem: madeira do tronco > raízes > folhas > galhos > casca do tronco > frutos. Para os micronutrientes as concentrações seguem a ordem: raízes > madeira do tronco > galhos > folhas > casca do tronco > frutos. A exportação de nutrientes pela intensidade da colheita dos componentes da biomassa, apresentou a seguinte tendência de distribuição no cenário de colheita 1 (remoção de 30% de folhas,+ 30% de galhos + 100% dos frutos): Mn > N > Cu > K > Mg > S > B > Ca > P > Zn > Fe. Considerando o cenário de colheita 2 (remoção de 50% de folhas, + 50% galhos + 100% dos frutos) a exportação de nutrientes teve a seguinte distribuição: Mn > N > Cu > K > Ca > Mg > S > B > P > Zn > Fe. Para o cenário de colheita 3 (remoção de 100% de folhas + 100% de galhos e todos os frutos) a exportação de nutrientes apresentou a seguinte distribuição: Mn > N > Cu > B > Mg > K > Ca > S > P > Zn > Fe.
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Santos, Francisco SÃrgio Ribeiro dos. "Production and nutrition in strawberry crop soil and hydroponic." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13165.
Анотація:
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorTraditional soil based strawberry production currently faces some obstacles, both by excessive use of pesticides, as the diseases caused by fungi and other pathogens and ergonomic difficulties of cultivating the soil. Strawberry soilless cultivation combined with greenhouse and the use of substrate promotes some advantages such as: eliminating the use of products for soil disinfection, precocity, increased yields, better crop management conditions and crop protection against adverse weather conditions, pest attacks and diseases.. The objective of the study was to evaluate yield and nutrition of four strawberry cultivars in three cropping systems in Serra da Ibiapaba â CearÃ. The experiment was conducted in 3 x 4 factorial design, randomized blocks, with three cultivation systems arranged in strips (soil, hydroponic in gutters and bags), with four strawberry cultivars (Oso Grande, Albion, and Camarosa and Festival) and five replications. Coconut fiber was used as substrate in the hydroponic systems. In the period between the sixth and thirty-eighth week after transplanting, the number and average fruit weight, yield per plant and yield were determined. From the beginning of flowering, leaves were collected every two months to determine the levels of macro and micronutrients. Hydroponic gutter and bag systems increased the number of fruits per plant, but did not increase average fruit weight. The strawberry yield in hydroponic cultivation system was superior to soil cultivation. Cultivar Festival presented more fruits than the other cultivars in hydroponic systems. The Oso Grande and Festival cultivars stood out as the average fruit weight and yield, respectively, and may be recommended for hydroponic cultivation for the region of Serra da Ibiapaba. Based on the leaf nutrient contents, it is suggested adjustments in concentrations of phosphorus and magnesium in the nutrient solution used in hydroponic strawberry crop. Keywords: Fragaria x ananassa, cultivar, nutrients, crop system,
O cultivo do morangueiro no solo enfrenta atualmente alguns entraves, tanto pelo uso excessivo de defensivos, como pelas doenÃas causadas por fungos e outros patÃgenos e as dificuldades ergonÃmicas do cultivo no solo. O cultivo em sistemas sem solo combinado com ambiente protegido e o uso de substrato proporciona algumas vantagens como: eliminaÃÃo do uso de produtos destinados à desinfecÃÃo do solo, antecipaÃÃo do inÃcio das colheitas, aumento da produÃÃo, proteÃÃo da cultura Ãs condiÃÃes meteorolÃgicas adversas, ataque de pragas e doenÃas e melhores condiÃÃes de manejo da cultura. O experimento teve como objetivo avaliar a produÃÃo e nutriÃÃo de quatro cultivares de morango em trÃs sistemas de cultivo na Serra da Ibiapaba â CearÃ. O experimento foi conduzido em esquema fatorial 3 x 4, em blocos casualizados, sendo trÃs sistemas de cultivo dispostos em faixa (solo, hidropÃnico em calhas e em s a c o l a s ), com quatro cultivares de morangueiro (Oso Grande, Albion, Camarosa e Festival), com cinco repetiÃÃes. No sistema hidropÃnico foi utilizado como substrato fibra de coco. No perÃodo entre a sexta e trigÃsima oitava semana apÃs o transplantio, foi determinado o nÃmero e peso mÃdio de frutos, produÃÃo por planta e produtividade. A partir do inÃcio do florescimento, foram coletadas a cada dois meses folhas para determinaÃÃo dos teores de macro e micronutrientes. Os sistemas hidropÃnicos em calha e em sacolas aumentaram o nÃmero de frutos por planta, porÃm nÃo aumentaram o peso mÃdio de frutos. A produtividade do morangueiro cultivado no sistema hidropÃnico foi superior ao cultivo no solo. A cultivar Festival apresentou maior nÃmero de frutos em relaÃÃo as demais cultivares nos sistemas hidropÃnicos. As cultivares Oso Grande e Festival destacaram-se quanto a peso mÃdio de frutos e produtividade, respectivamente, sendo recomendadas para cultivo hidropÃnico para regiÃo da Serra da Ibiapaba. Com base nos teores de nutirentes na folha sugere-se ajustes nas concentraÃÃes de fÃsforo e magnÃsio na soluÃÃo nutritiva utilizada no cultivo hidropÃnico do morangueiro. Palavras-chaves: Fragaria x ananassa, cultivar, sistema de cultivo, nutrientes.
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Cottes, Jeremy Jean-Guy. "Le couple Eh/pH du sol : sa mesure, son impact sur la mobilité des nutriments et la croissance du tournesol." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0079.
Анотація:
Ce travail de thèse s’inscrit dans un contexte d’agriculture durable qui vise à consommer de moins en moins d’intrants tout en maintenant des niveaux de production de biomasse croissante, aussi bien en termes de quantité que de qualité. De tels niveaux ne peuvent être atteints qu’à la condition que les végétaux cultivés puissent se développer dans des conditions optimales, et notamment avoir accès aux éléments minéraux essentiels à leur croissance. De nombreux facteurs interviennent dans la mise à disposition des nutriments présents dans le sol pour les cultures comme le pH ou le potentiel d’oxydo-réduction (Eh). Plusieurs auteurs ont montré que les plantes fonctionnaient au sein d’une gamme interne Eh/pH bien spécifique et qu’elles ont la capacité de modifier ces paramètres dans la rhizosphère pour assurer l’homéostasie intracellulaire. Cette étude a pour objectif final de contribuer à la compréhension des effets du potentiel redox du sol sur la mobilité et la mise à disposition des nutriments pour la plante. La difficulté réside dans la nécessité de réaliser les mesures aussi bien pour le Eh que le pH, in situ dans le sol et en présence de plantes. Bien que connaître le Eh sol soit essentiel, sa mesure reste complexe en raison du manque de fiabilité des protocoles proposés, de l’hétérogénéité du système poral du sol et de la variabilité temporelle des conditions pédoclimatiques. Ainsi, le premier défi relevé par ces travaux a été d’ordre métrologique. Cette thèse propose des avancées pratiques sur la mesure du Eh dans les sols en utilisant des électrodes combinées. Le dispositif a été appliqué au suivi d’une culture en pots (1L) de tournesols placés pendant 70 jours dans différentes conditions pédoclimatiques. Cette campagne a notamment permis d’évaluer les relations existantes entre le couple Eh /pH du sol et la forme chimique disponible des principaux nutriments présents dans celui-ci (N, P, K, Ca, Mg, S, Fe, Mn, B, Zn, Cu et Mo). Les travaux ont ainsi montré que l’azote et le fer étaient les variables clés déterminant le Eh des sols. Alors que certains éléments (N, Fe, Mn, S) sont directement dépendants des variations du Eh et du pH des sols, d’autres (Mg, Ca, P, Cu, Zn, Mo) voient leur disponibilité indirectement impactée. Considérant l’ensemble de ces résultats, la question posée a alors été de savoir si la mesure du Eh du sol permettrait, d’une quelconque manière, de fournir un indicateur capable de rendre compte de « l’état favorable » du sol dans lequel sont cultivés les plantes. Afin de répondre à ce besoin un nouveau paramètre, nommé Ehcumul a été proposé, à l’instar du degré jour qui décrit, en agronomie, les besoins en température des plantes pour leur développement. De fortes corrélations entre Ehcumul et la croissance des tournesols ont permis de confirmer qu’il existe bien des conditions optimales de Eh des sols : 440 mV/ENH, dans notre expérimentation. Plus les conditions s’éloignent de cette valeur optimale, et moins le tournesol produit de biomasse. Faisant l’hypothèse que l’activité biologique des sols pouvait jouer un rôle central sur les valeurs du Eh, le suivi du tournesol a également été mené sur des sols préalablement stérilisés par étuvage. Ayant été portés 5 jours à 105°C, ces sols ont vu leur teneur en carbone organique dissous (COD) bien supérieure aux autres, suite à une dégradation de la matière organique la plus labile. L’augmentation du COD a eu de multiples impacts, dont celui de maintenir une valeur de Eh relativement modérée. Ces résultats ouvrent des perspectives concernant l’impact des matières organiques du sol pour y maintenir des valeurs de potentiels d’oxydo-réduction optimales pour la croissance des végétauxThis work is part of a sustainable agriculture context that aims to consume fewer and fewer inputs while maintaining increasing biomass production levels, both in terms of quantity and quality. Such levels can only be achieved if cultivated plants can develop under optimal conditions, including access to the mineral elements essential for their growth. Many factors are involved in the availability of nutrients in the soil for crops such as pH or oxidation-reduction potential (Eh). Several authors have shown that plants grow within a specific Eh/pH range and are able to alter these parameters in the rhizosphere to ensure intracellular homeostasis. The final objective of this study is to understand the effects of soil redox potential on mobility and availability of nutrients to the plant. The need to carry out measurements for both Eh and pH, in situ in the soil with plants is a real matter. Measuring soil Eh is essential but complex due to the lack of measurement reliability resulting from high temporal variability and metrological challenges. This work proposes practical advancements for measuring Eh in soils using combined electrodes. The protocol was applied to monitor a sunflowers pot culture (1L) for a 70 days campaign under different soil and climate conditions. The relationships between soil Eh / pH and the availability of nutrients presents in the soil (N, P, K, Ca, Mg, S, Fe, Mn, B, Zn, Cu and Mo) has been analysed. This study has highlighted the impact of nitrogen and iron in soil Eh values. While some elements (N, Fe, Mn, S) are directly impacted by soil Eh and pH variations, others (Mg, Ca, P, Cu, Zn, Mo) have their mobility and availability indirectly affected. Considering all these results, the objective of this experiment was to determine if soil Eh would in any way provide an indicator that could represents the "favourable state" of soil for plants growth. To achieve this objective a new parameter, called Ehcumul, has been proposed, similar to the degree day, which describes, in agronomy, the temperature needs for plants growth. Strong correlations between Ehcumul and sunflower growth revealed the existence of optimal soil Eh conditions: 440 mV/ENH, in our experiment. Assuming that biological activity of the soils could play a central role in Eh values, sunflower monitoring was also carried out on soils previously sterilized by drying (105°C for 5 days). The dissolved organic carbon (DOC) contents of these soils is increased compared to non-sterilised soils, due to degradation of the most labile organic matter. The consequence was a moderated and constant Eh value. These results open up perspectives on the impact of soil organic matter to maintain optimal soil redox potential values for plant growth
46
Buchler, K. (Konrad). "Investigations of nutrient stress in some forestry areas of South Africa." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52897.
Анотація:
Thesis (MScFor)--Stellenbosch University 2002.ENGLISH ABSTRACT: One of the greatest .limitations to the productivity of a plantation forest is poor nutrient status of the soil. Empirical application of corrective treatments are marginally successful in some cases, but because of limited understanding of the soiltree system, most nutritional problems go unnoticed or are accepted as a conceivable growth constraint. The aim of this investigation was to identify nutrient growth problems through field observations and to determine means of confirming these nutrient imbalances. Poor and abnormal growth of pine trees in the following areas were investigated: (i) The North Eastern Cape: Ugie and Maclear Districts (ii) The Natal Midlands: Mooi River area (iii) Mpumalanga: .Graskop and Kaapsche Hoop areas (iv) Southwestern Cape: Jonkershoek Plantation The study was conducted as nursery trials at the University of Stellenbosch and field trials at the various locations. Soils from the different regions were collected and used as growing media to test the growth response of five timber species (Pinus patula, P. elliottii, P. taeda, P. greggii and Eucalyptus nitens) under controlled conditions to various nutrient treatments. Indicator plants (cauliflower and soya) were included in these bio-assays. In the field trials nutrients were applied to seedlings and established stands of various ages by means of foliar and soil application. In the nursery trials and the trials where seedlings were planted in the field, plant performance was measured by quantitative means. The reaction of established stands to nutrient treatments were however less vigorous and qualitative means (e.g. colour changes) were used for assessment. Field observations in the North Eastern Cape and the Natal Midlands indicated possible boron, iron and molybdenum deficiencies and thus the work concentrates on these elements. Foliar and soil analyses reinforced these observations with marginal to deficient levels for boron and molybdenum being detected. The yellowing of foliage during the dry season was symptomatic of ineffective nitrogen assimilation and pointed to a molybdenum deficiency while seasonal growth tip dieback, resm exudation, sinuous tree limbs and bushy trees were classical boron deficiency symptoms. Potted trials indicated positive reaction to the application of boron and molybdenum deficiency symptoms were observed on indicator plants. Conclusive evidence of a boron deficiency in some of the pot trials, the planted field trials and the tree evaluation field trials remain elusive due to toxicity experienced as a result of an over-application of the nutrient. The occurrence of multiple deficiencies (phosphorous and calcium) further complicated the findings. The Mpumalanga observations indicated severe nutrient imbalance due to manganese toxicity (strong iron antagonism). The discolouring of the foliage on some sites towards the end of the winter was thought to be an induced molybdenum deficiency on the weathered and acidic red soils. Positive reaction to molybdenum application occurred in a single. tree evaluation trial, but because of soil oxidisation during collection, the effect of manganese toxicity was diluted in the pot trials. Foliar analyses indicated that foliar application of iron was unsuccessful and that other means should be considered to ensure uptake of this nutrient.
AFRIKAANSE OPSOMMING: Die lae vrugbaarheid van grond is een van die grootste beperkings tot die produktiwiteit van plantasie bosbou. Empiriese toedienings van kunsmisstowwe is in sekere gevalle suksesvol tot die bekamping van onvrugbaarheid. Weens gebrekkige kennis t.o.v die grond-boom sisteem word baie van die voedingstof probleme egter onkundig oorgeslaan' of word dit as natuurlike beperking in die produksie konteks aanvaar. Die doel van hierdie ondersoek was om swak boomgroei in die veld waar te neem en om bevestigende metodes te vind waarmee hierdie probleme as voedingstoftekorte geëien kan word. Swak en abnormale boomgroei van denne is in die volgende gebiede ondersoek: (i) Die Noordoos Kaap: Ugie- en Maclear Distrikte (ii) Die Natal Middelande: Mooirivier area (iii) Mpumalanga: Graskop- en Kaapsche Hoop areas (iv) Suidwes Kaap: Jonkershoek Plantasie Die ondersoek is uitgevoer as kwekery proewe by die Universiteit van Stellenbosch en as veldproewe in die onderskeie areas. Grond is uit die verskilende gebiede versamel en as groeimeduim gebruik om die groei-reaksie van vyf verskillende houtspesies (Pinus patula, P. elliottii, P. taeda, P. greggii en Eucalyptus nitens) onder beheerde klimaatsomstandighede te ondersoek. Daar is ook gebruik gemaak van indikator spesies (blomkool en soya) vir diagnose van visuele tekort simptome. Beide saailinge en reeds gevestigde bome is in die veldproewe gebruik. Voedingstowwe is by aanplanting toegedien, of in die geval van groter bome, as blaar- of grondtoedienings. Waar dit moontlik was (meestal in die geval van die saailinge) is die reaksie op die toegediende voedingstowwe met kwantitatiewe metodes bepaal. Daar moes egter van alternatiewe kwalitatiewe metodes gebruik gemaak word om die reaksie by die ouer en groter bome te bepaal. Gevolglik is verandering in bladkleur t.o.v. 'n basiskleur onder andere as maatstaf gebruik. Waarnemings van swak boomgroei in die Noordoos Kaap en die Natal Middelande het gedui op moontlike boor, yster en/of molibdeen tekorte. Lae vlakke van hierdie elemente in blaar- en grondanalises het hierdie waarnemings bevestig. Die geel verkleuring van die naalde gedurende die droë seisoen is simptomaties van oneffektiewe stikstof assimilasie en dui op 'n molibdeen tekort. Die waarneming van seisoenale terugsterwing van groeipunte, gebuigde stamme en takke, gomuitskeiding en bome met bosagtige voorkoms is eienskappe van 'n boor tekort. In die potproewe was daar positiewe reaksie op die toediening van boor en tekort simptome van molibdeen is in die indikator plante waargeneem. In van die potproewe, die saailing veldproewe en ander veldproewe kon daar egter nie uitsluitsel tot die effektiwiteit van boor gevind word nie aangesien toedienings te heftig was en toksisiteit ervaar is. Diagnose van enkel element voedingstof tekorte word bemoeilik deur van die proewe wat ook dui op veelvoudige voedingstoftekorte (veral fosfaat en kalsium). In Mpumalanga is daar waargeneem dat drastiese voedingstof wanbalanse a.g.v. mangaan toksisiteit aanwesig is (veral 'n sterk Fe antagonisme). Die bladverkleuring op sekere proefopstande aan die einde van die winter is ook 'n aanduiding van geïnduseerde molibdeen tekorte wat op die verweerde en suur rooi gronde van die omgewing verwag kan word. Daar was dan ook positiewe reaksie op die toediening van molibdeen, hoewel slegs byeen proefopstand. Die inherente nadeel van potproewe is op die mangaanryk gronde geopenbaar deurdat belugting (gedurende grond versameling) die effek van mangaan toksisiteit verminder het. Die gebruik van blaaranalises is ook voordelig aangewend om te bepaal dat die toediening van yster as blaartoediening onsuksesvol was en dat ander metodes ondersoek moet word om opname van die element te verseker.
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Rodrigues, Fernando Antonio Vieira. "Disponibilidade de cobre e zinco para mudas de eucalipto em solos de Cerrado." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/5417.
Анотація:
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Previous issue date: 2009-02-18Conselho Nacional de Desenvolvimento Científico e Tecnológico
Brazil is one of the biggest producers of cellulose, paper and vegetal coal of the world, and the activities related to planted forests contribute to 3.5 % of the Gross Domestic Product (PIB) of the country. The eucalypt is the forest essence that stands out, with a planted area of 3.75 millions of hectares, and the state of Minas Gerais has about 28 % of this planted area. In Brazil, with the intensification of the clonal sivilculture, the management of genetic materials that are more productive and more nutritional demanding has increased the appearance of symptoms of micronutrients deficiency, mainly of B, and, more recently, of Cu and Zn, especially in areas of Cerrado. The aim of this study was to evaluate three methods of determining Cu and Zn availability (Mehlich-1, Mehlich-3 and DTPA pH 7.3) to eucalypts seedlings cultivated under greenhouse conditions, in samples of six soils from Minas Gerais state (one sample from João Pinheiro, two from Vazante, one from Três Marias and two from Curvelo) and the influence of the properties of the soil in the efficiency of these extractors. Were realized two experiments, one for each micronutrient. The treatments were arranged in a randomized block design, with four replications, in a factorial scheme of 6 x 5, corresponding to six soils and five doses of micronutrient. The doses were 0, 2, 4, 8 and 16 mg dm-3 of Cu and 0, 2.5, 5, 10 and 20 mg dm-3 of Zn, in the form of Cu and Zn chloride, respectively. After 70 days of growth, the plants were cut into two distinct portions, one being apical (apical third of all the branches of the plant) and the other being basal (the rest of the plant cut down near the ground level). The criticals levels of Cu and Zn in soils from Cerrado, to the growth of eucalypts seedlings, are equal or inferiors to 0.12 and 0.23 mg dm-3 by the Mehlich-1 and are equal or inferiors to 0.09 and 0.05 mg dm-3 by the DTPA, respectively. The concentrations of Cu and Zn in the soil and in the plant, as well as the respectives contents, increase with the elevation of the additional doses of these nutrients. The concentrations and the contents of Cu and Zn in the plant show close relation to the contents extracted by the three extractors. The concentrations of Cu and Zn extracted by Mehlich-1, Mehlich-3 and by DTPA were strongly correlated. The content of organic matter and the P- remanescent are the characteristics of the soils which most negatively influence in the recovering rates of Cu and Zn by the extractors Mehlich-1 and Mehlich-3, while for the DTPA, the recovering rates are more negatively influenced by the pH. The Mehlich-1 is the most recommended extractor to evaluate Cu and Zn availability to eucalypts seedlings. First because the method is easy to handle when compared to other methods, and second because it is a method which has already been used by the great majority of the labs in the country.
O Brasil é um dos maiores produtores de celulose, papel e carvão vegetal do mundo, e as atividades relacionadas às florestas plantadas contribuem com 3,5 % do Produto Interno Bruto (PIB) do país. O eucalipto é a essência florestal que se destaca, com uma área plantada de 3,75 milhões de hectares e o Estado de Minas Gerais possui em torno de 28 % dessa área plantada. No Brasil, com a intensificação da silvicultura clonal e o plantio de materiais genéticos mais produtivos e exigentes nutricionalmente têm aumentado o aparecimento de sintomas de deficiência de micronutrientes, principalmente de B, e, mais recentemente, de Cu e Zn, especialmente em áreas de Cerrado. Este trabalho teve por objetivo avaliar três métodos de determinação da disponibilidade de Cu e de Zn (Mehlich-1, Mehlich-3 e DTPA pH 7,3) para mudas de eucalipto cultivadas em casa de vegetação, em amostras de seis solos do Estado de Minas Gerais (um de João Pinheiro, dois de Vazante, um de Três Marias e dois de Curvelo) e a influência de propriedades do solo na eficiência desses extratores. Foram realizados dois experimentos, um para cada micronutriente. Os tratamentos foram arranjados no esquema fatorial 6 x 5, correspondendo a seis solos e cinco doses do micronutriente, com quatro repetições, em blocos ao acaso. As doses foram de 0, 2, 4, 8 e 16 mg dm-3 de Cu e de 0, 2,5, 5, 10 e 20 mg dm-3 de Zn, na forma de cloreto de Cu e Zn, respectivamente. Após 70 dias de crescimento, as plantas foram cortadas em duas porções distintas, sendo uma apical (terço apical de todos os ramos da planta) e a outra basal (restante da planta cortada rente ao solo). Os níveis críticos de Cu e de Zn em solos de Cerrado, para o crescimento de mudas de eucalipto, são iguais ou inferiores a 0,12 e 0,23 mg dm-3 pelo Mehlich-1 e iguais ou inferiores a 0,09 e 0,05 mg dm-3 pelo DTPA, respectivamente. Os teores de Cu e de Zn no solo e na planta, bem como os respectivos conteúdos, aumentam com a elevação das doses adicionadas desses nutrientes. Os teores e conteúdos de Cu e de Zn na planta mostram estreita relação com os teores extraídos pelos três extratores. Os teores de Cu e de Zn extraídos pelo Mehlich-1, Mehlich-3 e DTPA são altamente correlacionados entre si. O teor de matéria orgânica e o P-remanescente são características dos solos que mais influenciam negativamente nas taxas de recuperação de Cu e de Zn pelos extratores Mehlich-1 e Mehlich-3, enquanto que para o DTPA, as taxas de recuperação são mais influenciadas pelo pH. O Mehlich-1 é o extrator mais recomendado para avaliar a disponibilidade de Cu e de Zn para mudas de eucalipto, pela facilidade operacional deste método frente aos outros e por este já ser usado na grande maioria dos laboratórios do país.
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Yeap, Simon Guo Hong. "Implications of soil water repellence for crop growth and nutrition." Thesis, Yeap, Simon Guo Hong (2020) Implications of soil water repellence for crop growth and nutrition. PhD thesis, Murdoch University, 2020. https://researchrepository.murdoch.edu.au/id/eprint/59040/.
Анотація:
In water-limited environments, dryland crop and pasture production on water-repellent sandy soils is often constrained by reduced water infiltration, accentuated overland flow and soil erosion, unstable wetting patterns, and the development of preferential flow paths in the soil profile, which consequently cause considerable spatial heterogeneity in soil water content, increased prevalence of isolated dry zones, and decreased overall soil water retention. The same processes are also likely to affect soil nutrient bioavailability and plant nutrient uptake. Indeed, while problems with crop nutrition on water-repellent sandy soils have been reported by many Australian growers, the role of soil water repellence in crop nutrition has not been studied to date and the mechanisms remain unclear. While various methods exist to manage soil water repellence for improving crop and pasture production (e.g., deep soil cultivation, clay spreading, wetting agent application, stimulation of wax-degrading microorganisms, furrow/on-row sowing and water harvesting, and no-tillage and stubble retention), the outcomes for crop nutrition post-amelioration are not well understood.
Several field and glasshouse experiments were, therefore, conducted to assess the implications of soil water repellence and its management on crop growth and nutrition on several sandy soil types from the southwest region of Western Australia. Preliminary field results showed that soil water repellence, if left unmanaged, could adversely affect wheat plant density, shoot dry matter production, K nutrition, and grain yield on a Grey Bleached-Ferric Kandosol (deep grey sandy duplex soil) at Meckering with a moderate water repellence value of up to 1.6 M using the molarity of ethanol droplet (MED) test, supporting the hypothesis that soil water repellence can adversely affect crop growth, nutrition, and grain production. However, it was also revealed at another site, with a Ferric Chromosol (sandy loam yellow duplex soil) at Kojonup, that increased soil water repellence could also increase canola plant density, shoot dry matter production, Cu nutrition, and seed yield when sown with 1 L/ha of banded wetting agent, despite prolonged severe water repellence (MED of 3.4 M) throughout the growing season. Although the underlying mechanisms could not be established from this preliminary study, it was concluded that soil water repellence may have both adverse and beneficial implications, but specific effects on nutrient availability in the root zone and crop nutrition were not defined.
Additional field studies were conducted to assess the effect of soil management practices (spading, one-way plough, subsoil clay spreading, and blanket applications of wetting agent) to alleviate soil water repellence on crop growth and nutrition. While all treatments except for one-way ploughing alleviated soil water repellence, only spading significantly improved wheat emergence, shoot dry matter, K nutrition, and grain yield on a Grey Tenosol (pale deep sandy soil) at Badgingarra. By contrast, at Moora, one-way plough treatments improved canola shoot dry matter and nutrition (Ca, S, B, Cu, and Zn contents) but did not mitigate severe water-repellence on a Ferric Chromosol (sandy ironstone gravel duplex soil), and had no effect on plant density or seed yield. However, the improvements due to soil cultivation can be attributed to the alleviation of soil compaction, given that the alleviation of soil water repellence by blanket-applied wetting agent (50 L/ha) and subsoil clay spreading treatments (250 t/ha; 50 % clay; 159 mg K/kg) had negligible effect on crop growth, nutrition, and grain production. Alleviation of soil water repellence was, therefore, not important for crop production at the Badgingarra and Moora study sites, presumably due to the presence of other soil constraints.
To avoid the confounding effects from multiple limiting factors evident in the field studies, a series of controlled glasshouse experiments were conducted to examine the effects of topsoil water repellence, topsoil thickness, fertiliser placement, variable low water supply, plant density, and/or surface topography on soil water content, soil nutrient availability, and early wheat growth and nutrition in 27 L containers. All glasshouse experiments demonstrated that severely water-repellent topsoil with a wettable furrow, which ensured uniform seedling emergence, significantly increased wheat seedling development, tiller number, shoot dry matter production, and nutrition (especially N, P, and K) during the early vegetative stage in wheat (40-51 DAS), under low but regular water supply (3.4-5.4 mm every two days). The growth stimulation was attributed to in situ water harvesting caused by preferential flow in the wettable furrow which increased the soil wetting and root depth relative to the completely wettable topsoil treatments that exhibited an even but shallow wetting depth. The even but shallow wetting patterns in completely wettable treatments consequently led to an overall decrease in plant-available water and plant water use efficiency, resulting in poor wheat growth and nutrition, especially under a limited water supply. These findings underscore the high efficacy of in situ water harvesting for improving early wheat growth and nutrition on water-repellent soils relative to completely wettable soils, thus demonstrating a beneficial role of soil water repellence in crop growth and nutrition. Adopting in situ water harvesting principles (i.e., furrow sowing, banding wetting agent in the furrow, and using winged knife-points and/or press-wheels) can, therefore, be an effective strategy for managing crop growth and nutrition on water-repellent sandy soils by maximising the use efficiency of limited soil water supply during the crop establishment period.
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Bois, Claudette Hélène. "The effect of timber harvest and wildfire on soil physical and nutritional dynamics in two boreal forest ecosite types in eastern Manitoba /." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80229.
Анотація:
Forest ecosystems undergo both natural and human induced disturbances. Depending on disturbance type, soil physical and chemical parameters show different response patterns during the recovery phase. An added level of complication is the ecological site types occurring throughout a forested area. The identification of indicators of soil fertility and the successful emulation of a natural disturbance regime were the scope of this research.The research presented herein took place in the Manitoba Model Forest (MBMF), located in eastern Manitoba, where the natural disturbance regime is wildfire. Timber harvest strategies used in the area are designed to emulate a wildfire (5% retention of standing timber and extensive slash inputs) and clearcut harvesting. The objective of this study was to document changes in forest floor and soil properties prior to and following harvesting, and to compare these properties to those found in a small wildfire that burned in the MBMF in late summer 1998, which serves as a benchmark to the harvest. In the two study areas, both thin mineral soil (5--20 cm) and moderately deep mineral soil (20--100 cm) ecosite types were monitored at four dates over a two year period for soil physical and nutritional response patterns.
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Raphuthing, Manneheng Violet. "Association between geophagia and haematological parameters of iron deficiency anaemia amongst geophagic Qwa-Qwa women." Thesis, Bloemfontein: Central University of Technology, Free State, 2015. http://hdl.handle.net/11462/239.
Анотація:
Thesis (M. Tech. (Biomedical Technology)) -- Central University of Technology, Free State, [2014]Pica is the habitual eating of non-food substances by humans and animals. It has different subgroups and these are defined by the ingested substance. Moreover, geophagia is a type of pica that refers to the consistent eating of mostly earth and earth-like substances such as clay and soil. It is observed in both sexes, all age groups and in different ethnic groups around the world. There are many reasons people give for the practice of geophagia, such as culture, hunger and health being the most prominent. Geophagic materials differ in texture, colour and taste. Soil colour classification according to the Munsell soil classification, which uses hues, values and chroma, sometimes differ with the soil colour being noticeable with the naked eye. However, geophagic clays from Qwa-Qwa are white and contain kaoline. Geophagic materials are believed to augment mineral deficiency, especially magnesium, calcium and iron. Geophagia is practised mainly by females, especially during their child bearing years. Females are more prone to iron deficiency anaemia due to their monthly menstruation cycle. Iron deficiency is the most common cause of anaemia and is classified as hypochromic microcytic anaemia (HMA). This study focused on the health aspect of geophagia. The research question seeks to explore whether there is an association between geophagia and the haematological parameters of iron deficiency anaemia. Geophagia seems to be linked with the occurrence of anaemia, but not iron deficiency anaemia, although it is implied. It is not known if the practice of geophagia causes iron deficiency anaemia or if it is because of iron deficiency anaemia that people practise geophagia. A pilot study was done in 2007, and the results of that study prompted that this study be performed on a bigger scale. The lack of information regarding the quantity, frequency and type of geophagic material consumed the impact of geophagia on haematological parameters and the iron status of the geophagists made it important that the primary existence of the iii relationship be investigated. In addition, research to establish whether there is a relationship between geophagia and haematological parameters of iron deficiency anaemia, has not been undertaken in South Africa, especially on non-pregnant women. Geophagia seems to always be accompanied by the subject of iron deficiency anaemia and especially its prevalence in females. The bigger geophagia project was therefore an ideal opportunity to do a specific survey on geophagic women. This was a cross-sectional study, consisting of 36 control women and 47 geophagic women, aged between 18-45 years. The participants completed a questionnaire to determine the geophagic practices, which included the colour of the clay, how frequent the clay was consumed, how much was consumed and for how long it has been consumed. Nutritional status was assessed using a food frequency questionnaire. Blood was drawn to assess the haematological and iron status of the participants. The participants of the study were within the required age range, with no significant difference between the groups (p-value=0.7914). The most consumed colour of clay was white and white clay contains kaoline, which has the ability to absorb iron in the duodenum. The majority of the participants consumed 40 grams of clay on a daily basis, with most of the participants having done so for 5 years. Diet was ruled out as the cause of iron deficiency. The haematological parameters indicated that the geophagic group (43%) were inclined to have hypochromic microcytic anaemia, while a small percentage of control groups (8%) had HMA; this was revealed by the red cell parameters and red cell indices. In addition, the odds ratio for the haematological results revealed that the probability of a geophagic person developing anaemia was two times greater than that of a non-geophagic person. Platelet results partially ruled out bleeding as a cause of anaemia. The median red cell distribution width indicated that the iv geophagic group was inclined to have anisocytosis. The geophagic group was found to have iron deficiency (75%), whilst the control group had a small percentage with iron deficiency (22%), which was validated by the serum ferritin, serum iron and saturated transferrin (chemical analysis). The odds ratio revealed that the probability of a geophagic person being iron deficient is 3 times greater than that of a non-geophagic person. The strongest association is seen with iron study findings, because being iron deficient showed the highest odd ratio than the association with red cell morphology and even haemoglobin. Thus, participants were more iron deficient than suffering from iron deficiency anaemia. Inflammatory and parasitic indicators proved that inflammation and infection was uncommon in both groups, and therefore did not compromise the credibility of the iron study results. Inflammatory indicators (white blood cells, erythrocyte sedimentation rate and C-reactive protein) ruled out inflammation, whilst eosinophil count showed no indication of parasitic infection for both geophagic and control groups. To conclude, the study found that an association exists between geophagia and haematological parameters of iron deficiency anaemia amongst geophagic women in Qwa-Qwa, in that geophagic material contributes to iron deficiency anaemia.