Letteratura scientifica selezionata sul tema "Plant-soil relationships"
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Articoli di riviste sul tema "Plant-soil relationships"
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&NA;. "Soil-Plant Relationships". Soil Science 146, n. 3 (settembre 1988): 208. http://dx.doi.org/10.1097/00010694-198809000-00010.
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Lemoigne, Yves. "Soil-plant relationships, an ecological approach". Geobios 21, n. 2 (gennaio 1988): 260. http://dx.doi.org/10.1016/s0016-6995(88)80024-x.
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Lathwell, D. J., e T. L. Grove. "Soil-Plant Relationships in the Tropics". Annual Review of Ecology and Systematics 17, n. 1 (novembre 1986): 1–16. http://dx.doi.org/10.1146/annurev.es.17.110186.000245.
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Keymer, Daniel P., e Richard A. Lankau. "Disruption of plant-soil-microbial relationships influences plant growth". Journal of Ecology 105, n. 3 (16 gennaio 2017): 816–27. http://dx.doi.org/10.1111/1365-2745.12716.
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Marrs, R. H., e D. W. Jeffrey. "Soil-Plant Relationships: An Ecological Approach. (1987)." Journal of Applied Ecology 25, n. 1 (aprile 1988): 367. http://dx.doi.org/10.2307/2403637.
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Golley, Frank B. "Chemical plant-soil relationships in tropical forests". Journal of Tropical Ecology 2, n. 3 (agosto 1986): 219–29. http://dx.doi.org/10.1017/s0266467400000845.
Testo completoAbstract (sommario):
ABSTRACTPlant and soil samples collected from four tropical forest areas were used to examine the correlation between the chemical abundances in soil and vegetation. On fertile soils in Panama and Colombia soil concentrations of copper, manganese, cobalt and zinc were correlated with plant concentrations. Calcium, caesium, iron, lead, magnesium, phosphorus, potassium, sodium and strontium-concentrations were not correlated. Factor analysis of plant chemistry at nine sites showed very little commonality between sites, even of vegetation belonging to the same plant association. A copper, manganese, cobalt, zinc factor was not recognized except in one case. A similar study of plant soil correlation in Colombia supported the conclusions from Panama; for most elements there was little evidence for significant correlation between plant and soil concentrations.Analysis of plant-soil relationships on very infertile latosols with terra firme forest in the Amazon at San Carlos de Rio Negro, Venezuela and Manaus, Brazil revealed a soil effect on the statistical distributions of the elements in the plant biomass. This effect was strongest on the least fertile site at Manaus and was strongest for essential elements. The pattern of chemical distributions appears to be due to the fact that some species are capable of concentrating high levels of elements even under conditions of very low supply in the substrate.
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Pastor, John. "Soil-Plant Relationships: A Gordian Knot Remains Tied". Ecology 69, n. 3 (giugno 1988): 874. http://dx.doi.org/10.2307/1941038.
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Xi, Nianxun, Peter B. Adler, Dongxia Chen, Hangyu Wu, Jane A. Catford, Peter M. Bodegom, Michael Bahn, Kerri M. Crawford e Chengjin Chu. "Relationships between plant–soil feedbacks and functional traits". Journal of Ecology 109, n. 9 (12 luglio 2021): 3411–23. http://dx.doi.org/10.1111/1365-2745.13731.
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Siegel, S. M., e B. Z. Siegel. "Temperature determinants of plant-soil-air mercury relationships". Water, Air, and Soil Pollution 40, n. 3-4 (agosto 1988): 443–48. http://dx.doi.org/10.1007/bf00163747.
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Shand, C. A. "Nutrient Elements in Grassland: Soil-Plant-Animal Relationships". Grass and Forage Science 56, n. 2 (29 giugno 2001): 200. http://dx.doi.org/10.1046/j.1365-2494.2001.00255.x.
Testo completoTesi sul tema "Plant-soil relationships"
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Lam, Kin-san. "Plant establishment in compost/PFA amended soil /". Hong Kong : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17095268.
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Wong, Siu-wai. "Plant selection for revegetation projects in Hong Kong". Click to view the E-thesis via HKUTO, 1992. http://sunzi.lib.hku.hk/hkuto/record/B43893442.
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Newmann, Sarah McCarthy. "Plant-soil feedbacks in temperate and tropical forests". Diss., Connect to online resource - MSU authorized users, 2008.
Cerca il testo completoAbstract (sommario):
Thesis (Ph.D.)--Michigan State University. Dept. of Forestry Program in Ecology, Evolutionary Biology and Behavior, 2008.Title from PDF t.p. (viewed on July 13, 2009) Includes bibliographical references (p. 170-184). Also issued in print.
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Chanway, Christopher Peter. "Plant/bacteria coadaptation in a grass/legume pasture". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26972.
Testo completoAbstract (sommario):
The relationship between plants and rhizosphere bacteria collected from a 45 year old permanent pasture was investigated. Several methods of strain identification within Rhizobium trifolii were evaluated. Separation of bacterial isolates based on differences in intrinsic antibiotic resistance was not appropriate because strains developed hybrid resistance patterns when grown in a common broth.
Serological analyses of bacterial antigens using polyclonal antiserum yielded two reliable methods for identifying R. trifolii isolates. Agglutination and immunofluorescence procedures were not useful in distinguishing these strains but immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) were highly suitable. Adaptation of the ELISA allowed isolates to be identified directly from individual root nodules without first subculturing the bacteria.
A strain of Bacillus polymyxa isolated from the same pasture was shown to stimulate growth of crested wheatgrass (Agropyron cristatum L.) and white clover (Trifolium repens L.). The primary manifestation of the effect was increased root weight (P < 0.05), but shoot responses were also observed. Perennial ryegrass (Lolium perenne L.) generally reacted negatively to inoculation with this bacterium.
Further stimulation of growth was noted when ramets of the white clover genotype homologous to (sharing a common origin) B. polymyxa were inoculated in pure stands (P < 0.05). Clones of the homologous perennial ryegrass genotype also showed a yield increase from slightly below control levels to slightly above them when tested in a similar manner.
Detailed analysis of the crested wheatgrass response to inoculation revealed that bacterial production of indole acetic acid was the most likely cause of the growth stimulation. Other bacterial characteristics such as the ability to fix atmospheric nitrogen or to solubilize organic phosphorus were concluded to be unrelated to the growth response.
Co-adaptive compatibility between genotypes of L. perenne and T. repens was not apparent when the effect of R. trifolii was ignored. However, when clones of pasture plants that had been neighbours in the field were inoculated with R. trifolii isolated from root nodules of the "parental" clover genotype, biotic specialization between the pasture plants became evident. The magnitude of the effect, which was characterized by superior white clover yields (P < 0.05), could be largely accounted for by the presence of the adapted L. perenne/R. trifolii combinations, regardless of the white clover genotype. Since T. repens was the dominant component in the species mixture, these trends were also apparent when total forage biomass was analyzed (P < 0.05). However, ecological combining ability was found to be lowest in these associations (P < 0.05).
Similar experimentation with isolates of B. polymyxa (or B. polymyxa-like organisms) was performed. Again the grass/bacteria combination was shown to be influential in the growth response as the presence of homologous L. perenne/B. polymyxa combinations resulted in superior white clover and perennial ryegrass performance (P < 0.05).
When T. repens was inoculated with a mixture of R. trifolii strains, unrelated isolates formed more root nodules than did homologous ones (P < 0.05). The presence of perennial ryegrass did not mitigate this effect. However, when homologous R. trifolii was administered as a single strain inoculum, yield advantages in white clover were observed (P < 0.05). If B. pol ymyxa was present, homologous strains of R. trifolii tended to form most of the root nodules regardless of the T. repens or L. perenne genotypes. The significance of the yield advantages observed in various two and three-way plant/microbe genotype combinations is discussed with respect to above ground plant performance.Land and Food Systems, Faculty of
Graduate
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Buratti, James Paul. "Some soil-plant relationships of the halophyte, Salicornia europaea L". The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1399561518.
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Babcock, Esther. "Soil Testing and Plant Analysis Relationships for Irrigated Chile Production". Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/193428.
Testo completoAbstract (sommario):
In a field study of irrigated chile (Capsicum annum L.) production in southeastern Arizona and southwestern New Mexico from 2008 through 2009, soil and tissue test samples were analyzed for a full spectrum of nutrients at 16 different sites, including nitrogen (N) phosphorus (P), potassium (K), zinc (Zn), iron (Fe), and boron (B), with the objective of evaluating soil and tissue nutrient testing procedures and establishing basic testing guidelines and recommendations with respect to yield potentials. Results for soil and tissue analysis were correlated to yield results. The results provide estimates for baselines which can be tested through subsequent calibration experiments for the development of recommendations for critical soil and tissue test values. These soil test and plant nutrients values will be evaluated in subsequent experiments in an effort to better define fertilizer nutrient inputs in order to gain better nutrient management efficiencies in irrigated chile production systems.
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Jiang, Pingping. "Variability of soil hydraulic properties and estimation of plant-available water on claypan-soil landscapes". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4783.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Missouri-Columbia, 2007.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 September 25, 2007) Vita. Includes bibliographical references.
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Stoll, Manfred. "Effects of partial rootzone drying on grapevine physiology and fruit quality". Title page, contents and summary only, 2000. http://hdl.handle.net/2440/37734.
Testo completoAbstract (sommario):
Growth, productivity and fruit quality of grapevines are closely linked to soil water availability. Withholding of water for any length of time results in slowed growth. If drought continues yield may be lost. Vines can be manipulated to stimulate early defence mechanisms by decreasing soil water availability. By using an irrigation technique, which allows for separate zones with different soil moisture status, it is possible to stimulate response mechanisms of the root system which are normally related to water stress. The difficulty of separating 'wet' and 'dry' zones was initially overcome by using split-root plants with root systems divided between two containers. Such experiments on split-root model plants resulted in the development of an irrigation technique termed partial rootzone drying (PRD). Results from irrigation experiments using PRD have shown that changes in stomatal conductance and shoot growth are some of the major components affected (Dry et al., 1996). The idea of using irrigation as a tool to manipulate stress responses in this way had its origin in the concept that root- derived abscisic acid (ABA) was important in determining stomatal conductance (Loveys, 1984). Later experiments on split-root plants have demonstrated that many effects of water stress can be explained in terms of transport of chemical signals from roots to shoots without changes in plant water status (Gowing et al., 1990). The necessary chemical signals are provided by the dry roots, and the wet roots prevent the development of deleterious water deficits. The general hypothesis tested during this study was that partial drying of the root system gives rise to a change in the supply of root-derived chemical signals which determine changes in grapevine physiology, thereby affecting fruit quality. Experiments were conducted on split-root vines (Vitis vinifera L. cvs. Cabernet Sauvignon and Chardonnay) grown in pots of different sizes, on field-grown vines which had either their root system divided by a plastic membrane (Vitis vinifera L. cv. Cabernet Sauvignon on own roots or grafted on Ramsey rootstocks) or conventional vines with a non-divided root system (Vitis vinifera L. cv. Cabernet Sauvignon, Shiraz and Riesling) with a commercial PRD irrigation design. The irrigation treatments were vines receiving water on both sides (control) and PRD-treated vines, which only received water on one side at any time. The frequency of alternation of 'wet' and 'dry' sides was determined according to soil moisture and other influences such as rainfall and temperature. In most of the experiments the irrigation was alternated from one side to the other every 10 to 15 days. Chemical signals from roots: the role of ABA and cytokinins Studies on chemical signals have concentrated on ABA and cytokinins (CK). An improved stable isotope dilution protocol, which enables analysis of ABA and CK from the same tissue sample, was developed. Analysis of cytokinins focused on zeatin (Z), zeatin riboside (ZR), zeatin glucoside (ZG) and iso pentenyl adenine (iP). Roots are relatively inaccessible, particularly in field situations. To enable easier access to roots of field-grown vines, split-root vines were planted in a trench which was refilled with a sandy soil. This created a homogenous soil substrate and did not restrict root growth while still allowing access to roots under field conditions. Analyses of root samples of field-grown vines have shown that cytokinins and ABA may originate in roots and their concentrations can be substantially altered during an irrigation cycle. Alternating soil water conditions showed that [ABA] in roots on the 'dry' side was significantly higher compared with the 'wet' side. Due to a reduction in CK on the 'dry' side of PRD-treated vines, the ratio between ABA and CK was substantially changed during an irrigation cycle. The ABA levels in root tissue and in petiole xylem sap were negatively related to stomatal conductance. This further suggests that ABA, mostly synthesized on the 'dry' side of the root system, might be responsible for a decline in stomatal conductance. Furthermore, a higher pH of petiole xylem sap was observed in PRD-treated vines which may also contribute to the regulation of stomatal conductance. Studies on stomatal patchiness showed that non-uniform stomatal aperture occurred in field-grown vines under natural environmental conditions and was more abundant under PRD conditions. The degree of stomatal opening, determined by using a water infiltration technique, correlated with measurement of stomatal conductance. Exogenous application of a synthetic cytokinin (benzyl adenine) can override the possible ABA-mediated stomatal closure resulting from PRD treatment, providing further evidence for the in vivo role of these growth regulators in the control of stomatal conductance. The effect of benzyl adenine was transient, however, requiring repeated applications to sustain the reversal. In addition, CKs may also be important in influencing grapevine growth. Following several weeks of repeated spray applications with benzyl adenine, it was found that the development of lateral shoots in PRD-treated vines was enhanced compared to PRD-treated vines sprayed with water only. This supports the idea that the reduction in lateral shoot development seen in PRD-treated vines is due to a reduced production of CKs (Dry et al., 2000a). By measuring shoot growth rate it was found that one common feature of PRD-treated vines, which were not sprayed with CK, was a reduction of lateral shoot growth. It can therefore be speculated that the reduction in lateral growth is related to a reduced delivery of cytokinins from the roots. Zeatin and zeatin riboside concentration in shoot tips and prompt buds/young lateral shoots were reduced by the PRD treatment providing further evidence in support of this hypothesis. Water movement from 'wet' to 'dry' roots Roots, being a primary sensor of soil drying, play an important role in long- and short-term responses to PRD. Using stable isotopes of water and heat-pulse sap flow sensors water movement was traced from wet to dry roots in response to PRD. The redistribution of water from roots grown in a soil of high water potential to roots growing in a soil of low water potential may be of significance with regard to the movement of chemical signals and the control of water balance of roots. Measurements of the relative water content (RWC) have shown a slower decline of RWC of the 'dry' roots of PRD vines relative to roots of vines which received no water, despite similar water content in soil surrounding those roots. The redistribution of water may help to sustain the response to PRD for longer periods possibly releasing chemical signals and to support the activity of fine roots in drying soil. Field vines, irrigated with PRD over several growing seasons, altered their root distribution relative to the control vines. PRD caused a greater concentration of fine roots to grow in deeper soil layers and this may contribute to a better water stress avoidance. The effect on root growth may be augmented by the water movement and by the large difference in ABA to cytokinin ratio, which are also known to alter root growth. PRD makes more efficient use of available water In experiments where both control and PRD-treated vines received the same amount of water many differences between the vines were demonstrated. Under conditions where water supply was adequate for both treatments, the stomatal conductance and growth of the PRD-treated vines was restricted as has been observed in many previous experiments. As total water input was reduced, however, the stomatal conductance of PRD-treated vines became greater than control vines, suggesting that the latter were experiencing a degree of water stress, whereas the PRD-treated vines were not. This may have been due to the greater depth of water penetration in the case of the PRD-treated vines, where water was applied to a smaller soil surface area. This distinction between PRD-treated and control vines, at very low water application rates, was also reflected in pruning weights and crop yields which were actually greater in PRD-treated vines. It was concluded that at low water application rates, the PRD-treated vines were more tolerant of water stress and made more efficient use of available water. Reduction in vigor opens the canopy. The initial aim of the research which led to the development of PRD was to achieve better control of undesirable, excessive shoot and foliage growth which, from a viticultural point of view, has many disadvantages. Grapevine shoot growth rate responds very sensitively to drying soil conditions. The irrigation strategy used in the PRD experiments maintained a reduction of both main shoot and lateral shoot growth. In response to PRD a decrease in shoot growth rate and leaf area was observed. Much of the reduction in canopy biomass was due to a reduced leaf area associated with lateral shoots, thus influencing the canopy structure. This was one major factor improving the light penetration inside the canopy. Control of vegetative vigour results in a better exposure of the bunch zone to light and, as a consequence, in improved grape quality. It is likely that changes in canopy density, as a result of PRD, is causing changes in fruit quality components. Anthocyanin pigments such as derivatives of delphinidin, cyanidin, petunidin and peonidin were more abundant in berries from PRD vines; by comparison the concentration of the major anthocyanin, malvidin, was reduced. When leaves were deliberately removed from more vigorous control vines, which improved bunch exposure, the differences in fruit composition were much reduced. This further supports the idea that a more open canopy, in response to PRD, improves fruit quality by affecting the canopy structure. Fruit quality consequently determines the quality, style and value of the finished wine. Wines from this study have been produced and data on wine quality from commercial wineries are also available. Sensory evaluations have demonstrated that high wine quality from PRD-treated vineyards can be achieved without any yield-depressing effects. This study has provided evidence to support the original hypothesis. The major findings were: a) Chemical signals, altered under PRD and mostly originating from roots, play an important role in the root to shoot communication in grapevines. b) The movement of water from 'wet' to 'dry' soil layers may help to sustain chemical signals as a response of grapevines to PRD and to support the activity of fine roots in drying soil. c) A reduction in vegetative growth, in particular of lateral shoots, was sustained using PRD and affected the canopy structure which in turn, due to a better light penetration into the canopy, improved the fruit quality. d) The reduction in irrigation water applied did not have a detrimental effect on grape yield and thus the efficiency of water use was improved. e) Application of relatively low irrigation rates showed that PRD-treated vines were more tolerant of water stress and made more efficient use of available water.Thesis (Ph.D.)--Department of Horticulture, Viticulture and Oenology, 2000.
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Hanegreefs, Paul R. "Modeling of bending stresses generated in soil crusts by emerging seedlings". The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1284994148.
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Scanlan, Craig Anthony. "Processes and effects of root-induced changes to soil hydraulic properties". University of Western Australia. School of Earth and Environment, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0188.
Testo completoAbstract (sommario):
[Truncated abstract] Root-induced changes to soil hydraulic properties (SHP) are an essential component in understanding the hydrology of an ecosystem, and the resilience of these to climate change. However, at present our capacity to predict how roots will modify SHP and the consequences of this is limited because our knowledge of the processes and effects are highly fragmented. Also, current models used to investigate the relationship between plants and root-induced changes to SHP are based on empirical relationships which have limited applicability to the various and often contrasting ecosystems that occur. This thesis focuses specifically on the quantifying the processes by which roots modify SHP and developing models that can predict changes to these and the water balance. Both increase and decreases in saturated hydraulic conductivity have been attributed to the presence of roots. In general, decreases occur when the root system is relatively young, and increases occur when the roots senesce and begin to decay, creating voids for water flow. The evidence available suggests that the change in pore geometry created by roots is the dominant process by which roots modify SHP because they are more permanent and of a greater magnitude than changes to fluid properties or soil structure. We first quantified the effects of wheat roots on SHP of a coarse sand with a laboratory experiment where we measured changes in both SHP and the root system at 3, 5, 7 and 9 weeks after sowing (weeks). ... The main message that can be drawn from this thesis is that root-induced changes to SHP are dynamic, and dependent upon the combination of soil texture, connectivity of root-modified pores and the ratio of root radius to pore radius. Consequently, root-induced changes to the water balance have the same dependencies. The work in this thesis provides a significant first step towards improving our capacity to predict how roots modify soil hydraulic properties. By defining the range for the parameters used to predict how the soil is modified by roots, we are able to make quantitative assessments of how a property such as hydraulic conductivity will change for a realistic circumstance. Also , for the first time we have measured changes in soil hydraulic properties and roots and have been able to establish why a rapid change from a root-induced decrease to increase in Ks occurred. The link between physiological stage of the root system, and the changes that are likely to occur has implications for understanding how roots modify SHP: it may provide an effective tool for predicting when the switch from a decrease to increase occurs. Further work is required to test the validity of the assumptions we have made in our models that predict changes to SHP. While we have endeavoured to define the parameter space for those parameters that we have introduced, there is still some uncertainty about the connectivity of root-modified pores. Also, the parameterisation of the soil domain with roots is based upon work that measures 'fine' roots only which may not provide a true representation of the effect trees and perennial shrubs have on SHP. It is inevitable that root-induced changes to SHP will affect the fate of solutes in the soil, and temporal dynamics of root-induced changes to these may be particularly important for the timing of nutrient and pesticide leaching.
Libri sul tema "Plant-soil relationships"
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Jeffrey, David W. Soil~Plant Relationships. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6.
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Rendig, Victor V. Principles of soil-plant interrelationships. New York: McGraw-Hill, 1989.
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Whitehead, D. C., a cura di. Nutrient elements in grassland: soil-plant-animal relationships. Wallingford: CABI, 2000. http://dx.doi.org/10.1079/9780851994376.0000.
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Draycott, A. P., e D. R. Christenson, a cura di. Nutrients for sugar beet production: soil-plant relationships. Wallingford: CABI, 2003. http://dx.doi.org/10.1079/9780851996233.0000.
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Gregory, P. J., e Stephen Nortcliff. Soil conditions and plant growth. Hoboken [N.J.]: Wiley-Blackwell, 2012.
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M, Taylor H., a cura di. Principles of soil-plant interrelationships. New York: Mcgraw-hill, 1989.
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van, Breemen N., a cura di. Plant-induced soil changes: Processes and feedbacks. Dordrecht: Kluwer Academic Publishers, 1998.
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Amilcare, Porporato, a cura di. Ecohydrology of water-controlled ecosystems: Soil moisture and plant dynamics. Cambridge: Cambridge University Press, 2004.
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1946-, Lipiec Jerzy, a cura di. Soil physical conditions and plant roots. Boca Raton, Fla: CRC Press, 1990.
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A, Kirkby Ernest, a cura di. Principles of plant nutrition. 4a ed. Bern: International Potash Institute, 1987.
Cerca il testo completoCapitoli di libri sul tema "Plant-soil relationships"
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Jeffrey, David W. "Soil matrix and soil water". In Soil~Plant Relationships, 109–28. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_8.
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Jeffrey, David W. "Soil atmosphere and soil temperature". In Soil~Plant Relationships, 129–35. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_9.
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Jeffrey, David W. "Soil formation". In Soil~Plant Relationships, 97–108. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_7.
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Hanna, William J., e Thomas B. Hutcheson. "Soil-Plant Relationships". In Changing Patterns in Fertilizer Use, 141–62. Madison, WI, USA: Soil Science Society of America, 2012. http://dx.doi.org/10.2136/1968.changingpatterns.c6.
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Jeffrey, David W. "Plants, roots and ion absorption". In Soil~Plant Relationships, 3–17. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_1.
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Jeffrey, David W. "Some examples of mineral nutrient supply". In Soil~Plant Relationships, 136–49. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_10.
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Jeffrey, David W. "Measuring availability of nutrients and toxic ions". In Soil~Plant Relationships, 150–60. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_11.
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Jeffrey, David W. "Experimental approaches to the study of soil variables". In Soil~Plant Relationships, 161–71. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_12.
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Jeffrey, David W. "The autecology of two contrasting species". In Soil~Plant Relationships, 175–84. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_13.
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Jeffrey, David W. "Restoration of derelict land". In Soil~Plant Relationships, 185–201. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_14.
Testo completoAtti di convegni sul tema "Plant-soil relationships"
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Yue, Ming, Linjing Zhang, Fengxue Gu, Xiaoling Pan e Guifang Zhao. "The relationships between plant community species diversity and soil factors". In Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space, a cura di Xiaoling Pan, Wei Gao, Michael H. Glantz e Yoshiaki Honda. SPIE, 2003. http://dx.doi.org/10.1117/12.466697.
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Crescimanno, G., K. B. Marcum, C. Reina e A. Versaci. "Investigating soil–plant relationships for sustainable management of irrigation with saline water in a Sicilian vineyard". In WATER RESOURCES MANAGEMENT 2009. Southampton, UK: WIT Press, 2009. http://dx.doi.org/10.2495/wrm090471.
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Zaharioiu, Anca Maria, Roxana Elena Ionete, Claudia Sandru, Marius Constantinescu e Oana Romina Botoran. "ALTITUDINAL CHANGES IN TEMPERATE FORESTS FROM CARPATHIAN MOUNTAINS". In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/5.1/s20.001.
Testo completoAbstract (sommario):
This study investigated changes in carbon (C) and nitrogen (N) concentrations in the three components of the forest ecosystem (leaves, bark and soil) along an altitudinal gradient in the temperate forests of Romania. The properties and processes within the forest ecosystem are influenced by altitude. The leaves, litter and soil are important in the good development of the ecosystem and in the cycle of the elements. Plants extract the nutrients necessary for life and growth from the soil in which they carry out their entire activity. With the help of litter, the soil is supplied with nutrients useful for plants. The soil can be influenced by pH, being a physical factor, and in the forests of Romania it decreases with altitude, becoming acidic. In this paper, studies were performed to investigate the chemical components in the soil-water-plant chain, which highlights the importance of stoichiometric variation of nutrients in plant organs and their relationships with other components of the forest ecosystem.
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Tomić, Dalibor, Vladeta Stevović, Milomirka Madić, Miloš Marjanović, Nenad Pavlović, Đorđe Lazarević, Mirjana Petrović, Vladimir Zornić e Jasmina Knežević. "THE ROLE OF COBALT IN FORAGE LEGUMES". In 1st International Symposium on Biotechnology. University of Kragujevac, Faculty of Agronomy, 2023. http://dx.doi.org/10.46793/sbt28.105t.
Testo completoAbstract (sommario):
The growth and metabolism of plants, especially on acidic soils, largely depend on the concentration of cobalt (Co) in the soil, i.e. the rhizosphere. An optimal supply of cobalt is essential for N2 fixation of Rhizobium bacteria that are in symbiotic relationships with leguminous plants, influencing their better growth and supplying them with nitrogen. When there is a lack of Co in the plant, the organic production of legumes falls. Indirectly or directly, Co also affects other metabolic processes in plants. The aim of the work was to analyze the importance of optimal provision of forage legumes with cobalt for obtaining high and quality yields of forage and seeds.
5
Mkrtchian, Alexander. "MODELING PRESENT AND PROSPECTIVE DISTRIBUTION OF PHYTEUMA GENUS IN CARPATHIAN REGION WITH MACHINE LEARNING TECHNIQUES USING OPEN CLIMATIC AND SOIL DATA". In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b2/v3/17.
Testo completoAbstract (sommario):
"Species distribution modeling can be effectively carried out using open data and data analysis tools with machine learning techniques. Modeling of the distribution of Phyteuma genus in the Carpathian region has been carried out with data from the GBIF database, climatic data from the Worldclim database, and soil properties data from Soilgrids soil information system. Spatial distribution modeling was accomplished with machine learning techniques that have marked advantages over more traditional statistical methods, like the ability to fit complex nonlinear relationships common in ecology. Four methods have been examined: Maxent, Random Forest, Artificial Neural Networks (ANN), and Boosted Regression Trees. AUC and TSS criteria calculated for testing data with cross-validation have been applied for assessing the performance of the models and to tune their parameters. ANN with a reduced set of predictor variables (6 from initial 21) appeared to fare the best and was applied for predictive modeling. Prospective data based on future climate projections from Worldclim were input to the model to get the prospective distribution of the plant taxon considering expected climate changes under different RCPs"
6
GUŽYS, Saulius, e Stefanija MISEVIČIENĖ. "NITROGEN CYCLES IN CROP ROTATIONS DIFFERING IN FERTILIZATION". In Rural Development 2015. Aleksandras Stulginskis University, 2015. http://dx.doi.org/10.15544/rd.2015.058.
Testo completoAbstract (sommario):
The use of nitrogen fertilizer is becoming a global problem; however continuous fertilization with nitrogen ensures large and constant harvests. An 8 year research (2006–2013) was conducted to evaluate the relationships between differently fertilized cultivated plant rotations. The research was conducted in Lipliunai (Lithuania) in the agroecosystem with nitrogen metabolism in fields with deeper carbonaceous soil, i.e. Endocalcari Endohypogleyic Cambisol (CMg-n-w-can). The research area covered three drained plots where crop rotation of differently fertilized cereals and perennial grasses was applied. Samples of soil, water and plants were investigated in the Chemical Analysis Laboratory of the Aleksandras Stulginskis University certified by the Environment Ministry of the Republic of Lithuania. The greatest productivity was found in a crop rotation with higher fertilization (N32-140). In crop rotation with lower fertilization (N24-90) productivity of cereals and perennial grasses (N0-80) was 11–35 % lower. The highest amount of mineral soil nitrogen was found in cereal crop rotation with higher fertilization. It was influenced by fertilization and crop productivity. The lowest Nmin and Ntotal concentrations in drainage water were found in grasses crop rotation. Crop rotations of differently fertilized cereals increased nitrogen concentration in drainage water. Nmin concentration in water depended on crop productivity, quantity of mineral soil nitrogen, fertilization, and nitrogen balance. The lowest nitrogen leaching was found in the crop rotation of grasses. Cereal crop rotation increased nitrogen leaching by 12–42 %. The usage of all crop rotations resulted in a negative nitrogen balance, which essentially depended on fertilization with nitrogen fertilizer.
7
Batubara, Siti Fatimah, e Musfal. "Soil-plant-nutrient relationship on several rice varieties in irrigated paddy field". In INTERNATIONAL CONFERENCE ON ORGANIC AND APPLIED CHEMISTRY (ICOAC) 2022. AIP Publishing, 2024. http://dx.doi.org/10.1063/5.0184951.
Testo completo
8
Yurchuk, O., e Irina Svistova. "A METHOD OF SOIL BIOTESTING TO ASSESS THE RHIZOSPHERE EFFECT OF NATURAL AND ARTIFICIAL PHYTOCENOSES". In FORESTRY-BIOLOGICAL FOUNDATIONS OF SUSTAINABILITY OF NATURAL AND ARTIFICIAL PHYTOCOENOSES. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2024. http://dx.doi.org/10.58168/fbfsnap2024_195-201.
Testo completoAbstract (sommario):
The relationship between plants and the soil microbiome has been studied from the point of view of analyzing the stimulating effect of rhizodeposites on the phytotoxic activity of soil in natural and artificial phytocenoses using the biotesting method. Biotesting makes it possible to accurately assess the positive or negative effect of plant allelopathic substances on the rhizosphere zone without spending significant time and material resources. Basically, biotesting techniques are implemented using the analysis of aqueous extract, but a more reliable assessment of soil samples is the assessment of the solid soil phase. Therefore, the most accessible method for evaluating the stimulating effect of rhizodeposites is the method of biotesting on soil plates using a test plant. The use of an indicator plant organism makes it possible to study the impact on the soil environment of a combination of factors, both positive and negative, and to make an overall assessment of the toxicity of this environment based on their changes. The results of soil biotesting allow us to develop the most effective methods of tillage to increase its fertility.
9
Draganskaya, Maria, e Inna Savvicheva. "CULTIVATION OF LUPIN YELLOW IN THE CHANGED SOILAND CLIMATIC CONDITIONS NONCHERNOZEM ZONE". In Multifunctional adaptive feed production. ru: Federal Williams Research Center of Forage Production and Agroecology, 2020. http://dx.doi.org/10.33814/mak-2020-22-70-91-98.
Testo completoAbstract (sommario):
Features of cultivation of lupine yellow as a source of increase of fertility of sandy and sandy loam soils are designated. In the changed soil and climatic conditions, work is carried out in the direction of creating varieties of different economic use: seeds, green mass, silage, grain fodder adapted to this zone and to various diseases with an optimal relationship between the host plant and the pathogen.
10
Sasanelli, Nicola, Ion Toderas, Elena Iurcu-Straistaru, Stefan Rusu, Varvara Migunova e Alena Konrat. "Yield losses caused by plant parasitic nematodes graphical estimation". In International symposium ”Functional ecology of animals” dedicated to the 70th anniversary from the birth of academician Ion Toderas. Institute of Zoology, Republic of Moldova, 2019. http://dx.doi.org/10.53937/9789975315975.60.
Testo completoAbstract (sommario):
Curves for graphical estimation of yield losses caused by plant parasitic nematodes were calculated on the basis of the relationship between soil nematode population density and damage to plants as described by the Seinhort’s equation y = m + (1 – m) z(P-T). By a logarithmic transformation this equation was transformed as y = m + (1 – m) 1.05[(P/-T) + 1] and solved considering values of tolerance limit (T) and the minimum relative yield (m) from the literature. The obtained curves that can be defined “Curves of nematode-pathogenicity” allow a quick and easy evaluation of yield losses for each known crop-nematode relationship.
Rapporti di organizzazioni sul tema "Plant-soil relationships"
1
D. L. Kelting e H. L. Allen. Influence of surface and subsurface tillage on soil physical properties and soil/plant relationships of planted loblolly pine. Office of Scientific and Technical Information (OSTI), maggio 2000. http://dx.doi.org/10.2172/758307.
Testo completo
2
Zhang, Renduo, e David Russo. Scale-dependency and spatial variability of soil hydraulic properties. United States Department of Agriculture, novembre 2004. http://dx.doi.org/10.32747/2004.7587220.bard.
Testo completoAbstract (sommario):
Water resources assessment and protection requires quantitative descriptions of field-scale water flow and contaminant transport through the subsurface, which, in turn, require reliable information about soil hydraulic properties. However, much is still unknown concerning hydraulic properties and flow behavior in heterogeneous soils. Especially, relationships of hydraulic properties changing with measured scales are poorly understood. Soil hydraulic properties are usually measured at a small scale and used for quantifying flow and transport in large scales, which causes misleading results. Therefore, determination of scale-dependent and spatial variability of soil hydraulic properties provides the essential information for quantifying water flow and chemical transport through the subsurface, which are the key processes for detection of potential agricultural/industrial contaminants, reduction of agricultural chemical movement, improvement of soil and water quality, and increase of agricultural productivity. The original research objectives of this project were: 1. to measure soil hydraulic properties at different locations and different scales at large fields; 2. to develop scale-dependent relationships of soil hydraulic properties; and 3. to determine spatial variability and heterogeneity of soil hydraulic properties as a function of measurement scales. The US investigators conducted field and lab experiments to measure soil hydraulic properties at different locations and different scales. Based on the field and lab experiments, a well-structured database of soil physical and hydraulic properties was developed. The database was used to study scale-dependency, spatial variability, and heterogeneity of soil hydraulic properties. An improved method was developed for calculating hydraulic properties based on infiltration data from the disc infiltrometer. Compared with the other methods, the proposed method provided more accurate and stable estimations of the hydraulic conductivity and macroscopic capillary length, using infiltration data collected atshort experiment periods. We also developed scale-dependent relationships of soil hydraulic properties using the fractal and geostatistical characterization. The research effort of the Israeli research team concentrates on tasks along the second objective. The main accomplishment of this effort is that we succeed to derive first-order, upscaled (block effective) conductivity tensor, K'ᵢⱼ, and time-dependent dispersion tensor, D'ᵢⱼ, i,j=1,2,3, for steady-state flow in three-dimensional, partially saturated, heterogeneous formations, for length-scales comparable with those of the formation heterogeneity. Numerical simulations designed to test the applicability of the upscaling methodology to more general situations involving complex, transient flow regimes originating from periodic rain/irrigation events and water uptake by plant roots suggested that even in this complicated case, the upscaling methodology essentially compensated for the loss of sub-grid-scale variations of the velocity field caused by coarse discretization of the flow domain. These results have significant implications with respect to the development of field-scale solute transport models capable of simulating complex real-world scenarios in the subsurface, and, in turn, are essential for the assessment of the threat posed by contamination from agricultural and/or industrial sources.
3
Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion e Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, ottobre 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Testo completoAbstract (sommario):
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
4
Савосько, Василь Миколайович, Наталія Вікторівна Товстоляк, Юрій Васильович Лихолат e Іван Панасович Григорюк. Structure and Diversity of Urban Park Stands at Kryvyi Rih Ore-Mining & Metallurgical District, Central Ukraine. Podgorica, 2020. http://dx.doi.org/10.31812/123456789/3946.
Testo completoAbstract (sommario):
The present study examines the relationships between structure (floristic composition, dendrometric parameters), diversity (diversity and evenness indexes) of urban forest park stands and the ecological (soil fertility, soil moisture), environmental factors (air pollution). The study is based on the forest park stands inventory data, performed from 2012 to 2017 in Kryvyi Rih City, Central Ukraine. The floristic compositions of the urban forest park stands are poor. There are only 23 species that belong to 14 families and 12 genera. More families were represented by at least more than 2% of taxon diversity. While Ulmaceae (2 genera, 4 species–17,39 %), Fabaceae (3 genera, 2 species–17,39 %), Aсеrасеае (1 genera, 4 species–17,39 %) were the most representative families. It was established that at forest park the values of stand density varied from 490 to 660 trees*ha-1, stem heights were from 26 to 31 m, stem diameters were from 13 to 17 cm, stand basal area were from 32 to 49 m2*ha-1, stand volume were from 200 to 415 m3*ha-1. the values of relative stem heights were from 0,63 to 0,82 m*year-1, relative stem diameters were from 0,31 to 0,43 cm*year-1, relative stand basal area were from 0,80 to 1,19 m2*ha-1*year-1, relative stand volume were from 5,45 to 10,28 m3*ha-1*year-1. The varied values of the forest park stands index (Shannon-Wiener diversity index from 0,75 to 1,61, Pielou‟s evenness index from 0,53 to 0,86, Simpson‟s diversity from 0,24 to 0,60, Margalef‟s diversity index from 0,87 to 6,97) indicate the ecological instability of these woody plant communities. Current state of the urban forest park stands determined by the combined influence of ecological (soil fertility, soil moisture) and environmental factors (air pollution).
5
Freeman, Stanley, e Daniel Legard. Epidemiology and Etiology of Colletotrichum Species Causing Strawberry Diseases. United States Department of Agriculture, settembre 2001. http://dx.doi.org/10.32747/2001.7695845.bard.
Testo completoAbstract (sommario):
Diseases caused by Colletotrichum spp. are one of the most important limitations on international strawberry production, affecting all vegetative and fruiting parts of the plant. From 1995 to 1997, C. acutatum infections reached epidemic levels in Israeli strawberry nurseries, causing extensive loss of transplants in fruit-bearing fields and additional reductions in yield. Although C. acutatum also occurs on strawberry in Florida, recent crown rot epidemics have been primarily caused by C. gloeosporioides. Little is known about the basic epidemiology of these important diseases on strawberry. The source of initial inoculum for epidemics in Israel, Florida (other US states including California) and the rest of the world is not well understood. Subspecies relationships between Colletotrichum isolates that cause the different diseases on strawberry (i.e. attack different tissues) are also not well understood. Objectives of this proposal were to detennine the potential of infested soil, strawberry debris and other hosts as sources of primary inoculum for strawberry diseases caused by Colletotrichum spp. in Israel and Florida. In addition, traditional (ie. morphological characteristics, benomyl sensitivity, vegetative compatibility grouping) and DNA based methods were used to investigate the etiology of these diseases in order to resolve epidemiologically important subspecies variation. In Israel it was found that C. gloeosporioides and C. acutatum infecting strawberry could remain viable in sterilized soil for up to one year and in methyl-bromide fumigated soil for up to 4 months; inoculum in mummified fruit remained viable for at least 5 months under field conditions whereas that in infected crowns was not recovered. Therefore, the contribution of these inocula to disease epidemics should be considered. The host range and specificity of C. acutatum from strawberry was examined on pepper, eggplant, tomato, bean and strawberry under greenhouse conditions. The fungus was recovered from all plant species over a three-month period but caused disease symptoms only on strawberry. C. acutatum was also isolated from healthy looking, asymptomatic plants of the weed species, Vicia and Conyza, growing in infected strawberry fruiting fields. Isolates of C. acutatum originating from strawberry and anemone infected both plant species in artificial inoculations. The habitation of a large number of plant species including weeds by C. acutatum suggests that although it causes disease only on strawberry and anemone in Israel, these plants may serve as a potential inoculum source for strawberry infection and pennit survival of the pathogen between seasons. In Florida, isolates of Colletotrichum spp. from diseased strawberry fruit and crowns were evaluated to detennine their etiology and the genetic diversity of the pathogens. Only C. acutatum was recovered from fruit and C. gloeosporioides were the main species recovered from crowns. These isolates were evaluated at 40 putative genetic loci using random amplified polymorphic DNA (RAPD). Genetic analysis of RAPD markers revealed that the level of linkage disequilibrium among polymorphic loci in C. gloeosporioides suggested that they were a sexually reproducing population. Under field conditions in Florida, it was detennined that C. gloeosporioides in buried crowns survived
6
Schweiger, E., Joanna Lemly, Dana Witwicki, Kirk Sherrill, Ruth Whittington, Lewis Messner, Erin Cubley, Katherine Haynes e Sonya Daw. Florissant Fossil Beds National Monument wetland ecological integrity: 2009?2019 synthesis report. National Park Service, 2023. http://dx.doi.org/10.36967/2300778.
Testo completoAbstract (sommario):
Wetlands at Florissant Fossil Beds National Monument (FLFO) are important because they are biodiversity hotspots and support iconic wildlife. They also provide valuable ?ecosystem services? such as attenuating floods, storing water, recharging aquifers, stabilizing and sequestering sediment, storing carbon, enhancing water quality, and cycling nutrients. This report summarizes 11 years (2009?2019) of wetland monitoring in three sentinel wetland complexes in FLFO. Monitoring included annual samples of 10 wet meadow and fen wetland sites in these complexes. We partition the data into a baseline period encompassing the first three years of our work for which we estimate conditions using a variety of indicators, or vital signs. We then estimate trend across the whole period of record. Results are compared to assessment points that allow us to interpret results in a management relevant context. We collected data on vascular plant species composition, woody species stand structure and damage and mortality of woody stems, soil chemistry, groundwater chemistry, and depth to water at shallow groundwater wells in each complex. We also documented human disturbance in and around each wetland complex. Projections suggest that climate change will likely reduce the number and extent of wetlands in the park and cause declines in the condition of associated flora and fauna and critical ecological functions, such as carbon and water storage. Human use can cause disturbance to wetlands across multiple scales and has well documented relationships with wetland condition. Wetlands at FLFO were impacted by over a century of cattle ranching and other human uses that increased soil erosion, altered hydrology, and made the area more susceptible to invasion by exotic plant species. Disturbance indicators at both a landscape and smaller scale generally showed an intermediate level of disturbance in and around our sentinel sites. Across all sites and indicators, we generally saw lower groundwater levels in response to drought conditions in 2010?2013 and in 2017?2018. However, groundwater at the Hornbek complex responded differently, potentially benefiting from a restoration project that filled incised channels in late summer 2012. Vegetation indicators showed relatively stable and healthy conditions in the park, except for native species cover, which was in intermediate condition.
7
Bonfil, David J., Daniel S. Long e Yafit Cohen. Remote Sensing of Crop Physiological Parameters for Improved Nitrogen Management in Semi-Arid Wheat Production Systems. United States Department of Agriculture, gennaio 2008. http://dx.doi.org/10.32747/2008.7696531.bard.
Testo completoAbstract (sommario):
To reduce financial risk and N losses to the environment, fertilization methods are needed that improve NUE and increase the quality of wheat. In the literature, ample attention is given to grid-based and zone-based soil testing to determine the soil N available early in the growing season. Plus, information is available on in-season N topdressing applications as a means of improving GPC. However, the vast majority of research has focused on wheat that is grown under N limiting conditions in sub-humid regions and irrigated fields. Less attention has been given to wheat in dryland that is water limited. The objectives of this study were to: (1) determine accuracy in determining GPC of HRSW in Israel and SWWW in Oregon using on-combine optical sensors under field conditions; (2) develop a quantitative relationship between image spectral reflectance and effective crop physiological parameters; (3) develop an operational precision N management procedure that combines variable-rate N recommendations at planting as derived from maps of grain yield, GPC, and test weight; and at mid-season as derived from quantitative relationships, remote sensing, and the DSS; and (4) address the economic and technology-transfer aspects of producers’ needs. Results from the research suggest that optical sensing and the DSS can be used for estimating the N status of dryland wheat and deciding whether additional N is needed to improve GPC. Significant findings include: 1. In-line NIR reflectance spectroscopy can be used to rapidly and accurately (SEP <5.0 mg g⁻¹) measure GPC of a grain stream conveyed by an auger. 2. On-combine NIR spectroscopy can be used to accurately estimate (R² < 0.88) grain test weight across fields. 3. Precision N management based on N removal increases GPC, grain yield, and profitability in rainfed wheat. 4. Hyperspectral SI and partial least squares (PLS) models have excellent potential for estimation of biomass, and water and N contents of wheat. 5. A novel heading index can be used to monitor spike emergence of wheat with classification accuracy between 53 and 83%. 6. Index MCARI/MTVI2 promises to improve remote sensing of wheat N status where water- not soil N fertility, is the main driver of plant growth. Important features include: (a) computable from commercial aerospace imagery that include the red edge waveband, (b) sensitive to Chl and resistant to variation in crop biomass, and (c) accommodates variation in soil reflectance. Findings #1 and #2 above enable growers to further implement an efficient, low cost PNM approach using commercially available on-combine optical sensors. Finding #3 suggests that profit opportunities may exist from PNM based on information from on-combine sensing and aerospace remote sensing. Finding #4, with its emphasis on data retrieval and accuracy, enhances the potential usefulness of a DSS as a tool for field crop management. Finding #5 enables land managers to use a DSS to ascertain at mid-season whether a wheat crop should be harvested for grain or forage. Finding #6a expands potential commercial opportunities of MS imagery and thus has special importance to a majority of aerospace imaging firms specializing in the acquisition and utilization of these data. Finding #6b on index MCARI/MVTI2 has great potential to expand use of ground-based sensing and in-season N management to millions of hectares of land in semiarid environments where water- not N, is the main determinant of grain yield. Finding #6c demonstrates that MCARI/MTVI2 may alleviate the requirement of multiple N-rich reference strips to account for soil differences within farm fields. This simplicity will be less demanding of grower resources, promising substantially greater acceptance of sensing technologies for in-season N management.
8
Chen, Yona, Jeffrey Buyer e Yitzhak Hadar. Microbial Activity in the Rhizosphere in Relation to the Iron Nutrition of Plants. United States Department of Agriculture, ottobre 1993. http://dx.doi.org/10.32747/1993.7613020.bard.
Testo completoAbstract (sommario):
Iron is the fourth most abundant element in the soil, but since it forms insoluble hydroxides at neutral and basic pH, it often falls short of meeting the basic requirements of plants and microorganisms. Most aerobic and facultative aerobic microorganisms possess a high-affinity Fe transport system in which siderophores are excreted and the consequent Fe complex is taken up via a cognate specific receptor and a transport pathway. The role of the siderophore in Fe uptake by plants and microorganisms was the focus of this study. In this research Rhizopus arrhizus was found to produce a novel siderophore named Rhizoferrin when grown under Fe deficiency. This compound was purified and its chemical structure was elucidated. Fe-Rhizoferrin was found to alleviate Fe deficiency when applied to several plants grown in nutrient solutions. It was concluded that Fe-Rhizoferrin is the most efficient Fe source for plants when compared with other among microbial siderophores known to date and its activity equals that of the most efficient synthetic commercial iron fertilizer-Fe EDDHA. Siderophores produced by several rhizosphere organisms including Rhizopus Pseudomonas were purified. Monoclonal antibodies were produced and used to develop a method for detection of the siderophores produced by plant-growth-promoting microorganisms in barley rhizosphere. The presence of an Fe-ferrichrome uptake in fluorescent Pseudomonas spp. was demonstrated, and its structural requirements were mapped in P. putida with the help of biomimetic ferrichrome analogs. Using competition experiments, it was shown that FOB, Cop B and FC share at least one common determinant in their uptake pathway. Since FC analogs did not affect FOB or Cop-mediated 55Fe uptake, it could be concluded that these siderophores make use of a different receptor(s) than FC. Therefore, recognition of Cop, FOB and FC proceeds through different receptors having different structural requirements. On the other hand, the phytosiderophores mugineic acid (MA and DMA), were utilized indirectly via ligand exchange by P. putida. Receptors from different biological systems seem to differ in their structural requirements for siderophore recognition and uptake. The design of genus- or species-specific drugs, probes or chemicals, along with an understanding of plant-microbe and microbe-microbe relationships as well as developing methods to detect siderophores using monoclonal antibodies are useful for manipulating the composition of the rhizosphere microbial population for better plant growth, Fe-nutrition and protection from diseases.
9
Kistler, Harold Corby, e Talma Katan. Identification of DNA Unique to the Tomato Fusarium Wilt and Crown Rot Pathogens. United States Department of Agriculture, settembre 1995. http://dx.doi.org/10.32747/1995.7571359.bard.
Testo completoAbstract (sommario):
Wilt and crown rot are two important diseases of tomato caused by different strains ("formae speciales") of the fungus, Fusarium oxysporum. While both pathogens are members of the same fungal species, each differs genetically and resistance to the diseases is controlled by different genes in the plant. Additionally, the formae speciales differ in their ecology (e.g. optimal temperature of disease development) and epidemiology. Nevertheless, the distinction between these diseases based on symptoms alone may be unclear due to overlapping symptomatology. We have found in our research that the ambiguity of the pathogens is further confounded because strains causing tomato wilt or crown rot each may belong to several genetically and phylogenetically distinct lineages of F. oxysporum. Furthermore, individual lineages of the pathogen causing wilt or crown rot may themselves be very closely related. The diseases share the characteristic that the pathogen's inoculum may be aerially dispersed. This work has revealed a complex evolutionary relationship among lineages of the pathogens that makes development of molecular diagnostic methods more difficult than originally anticipated. However, the degree of diversity found in these soil-borne pathogens has allowed study of their population genetics and patterns of dispersal in agricultural settings.
10
Jury, William A., e David Russo. Characterization of Field-Scale Solute Transport in Spatially Variable Unsaturated Field Soils. United States Department of Agriculture, gennaio 1994. http://dx.doi.org/10.32747/1994.7568772.bard.
Testo completoAbstract (sommario):
This report describes activity conducted in several lines of research associated with field-scale water and solute processes. A major effort was put forth developing a stochastic continuum analysis for an important class of problems involving flow of reactive and non reactive chemicals under steady unsaturated flow. The field-scale velocity covariance tensor has been derived from local soil properties and their variability, producing a large-scale description of the medium that embodies all of the local variability in a statistical sense. Special cases of anisotropic medium properties not aligned along the flow direction of spatially variable solute sorption were analysed in detail, revealing a dependence of solute spreading on subtle features of the variability of the medium, such as cross-correlations between sorption and conductivity. A novel method was developed and tested for measuring hydraulic conductivity at the scale of observation through the interpretation of a solute transport outflow curve as a stochastic-convective process. This undertaking provided a host of new K(q) relationships for existing solute experiments and also laid the foundation for future work developing a self-consistent description of flow and transport under these conditions. Numerical codes were developed for calculating K(q) functions for a variety of solute pulse outflow shapes, including lognormal, Fickian, Mobile-Immobile water, and bimodal. Testing of this new approach against conventional methodology was mixed, and agreed most closely when the assumptions of the new method were met. We conclude that this procedure offers a valuable alternative to conventional methods of measuring K(q), particularly when the application of the method is at a scale (e.g. and agricultural field) that is large compared to the common scale at which conventional K(q) devices operate. The same problem was approached from a numerical perspective, by studying the feasibility of inverting a solute outflow signal to yield the hydraulic parameters of the medium that housed the experiment. We found that the inverse problem was solvable under certain conditions, depending on the amount of noise in the signal and the degree of heterogeneity in the medium. A realistic three dimensional model of transient water and solute movement in a heterogeneous medium that contains plant roots was developed and tested. The approach taken was to generate a single realization of this complex flow event, and examine the results to see whether features were present that might be overlooked in less sophisticated model efforts. One such feature revealed is transverse dispersion, which is a critically important component in the development of macrodispersion in the longitudinal direction. The lateral mixing that was observed greatly exceeded that predicted from simpler approaches, suggesting that at least part of the important physics of the mixing process is embedded in the complexity of three dimensional flow. Another important finding was the observation that variability can produce a pseudo-kinetic behavior for solute adsorption, even when the local models used are equilibrium.