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1
Ozgen, Senay, Mustafa Ozgen e Jiwan P. Palta. "556 Influence of Supplemental Calcium Fertilization on Potato Tuber Size and Tuber Number". HortScience 34, n. 3 (giugno 1999): 542B—542. http://dx.doi.org/10.21273/hortsci.34.3.542b.
Testo completoAbstract (sommario):
Several recent studies, including from our laboratory, have provided evidence that by improving tuber calcium level, we can improve tuber quality such as low internal defects and better storability. The purpose of this study was to be determine the influence of supplemental calcium fertilization on tuber size and tuber number. For this purpose, plantlets of Solanum tuberosum cv. Russet Burbank raised in tissue culture were planted in 20-L pots filled with sandy loam soil with pH of 6.9 and soil calcium level of 350 ppm. All treatments received same total amount of nitrogen (at the rate of 280 kg·ha–1). Five treatments were evaluated: i) nonsplit nitrogen (from ammonium nitrate), ii) split nitrogen (from ammonium nitrate), iii) split nitrogen + gypsum, iv) split nitrogen (from liquid nitrogen) + calcium chloride, and v) split nitrogen (from calcium nitrate). The total calcium was applied at the rate of 168 kg·ha–1. Gypsum application was made at 4 weeks after planting, and other sources of calcium were applied on a split schedule (equally split at 4, 6, 8 weeks after planting). Four months after planting, tubers were harvested and evaluated. In general, all calcium treatments had lower tuber number and greater tuber size compared to the nonsplit nitrogen control. The percentage of total A-grade tubers as well as the percentage yield from A-grade tubers was increased by all calcium applications. These results suggest that calcium content I the soil can influence both potato tuber number and tuber size.
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Diggle, AJ, e JW Bowden. "The response of wheat tops and roots grown in a leaching environment to rates of nitrogen added as calcium nitrate or organic residues containing 1, 2 or 6% nitrogen". Australian Journal of Agricultural Research 42, n. 7 (1991): 1053. http://dx.doi.org/10.1071/ar9911053.
Testo completoAbstract (sommario):
Wheat was grown under leaching conditions in a glasshouse in columns of a loamy sand soil to which nitrogen had been added in the form of calcium nitrate or organic materials containing 1, 2 or 6% nitrogen. All materials were added at a range of rates calculated on an elemental nitrogen basis, so that comparisons could be made between materials at the same level of nitrogen addition. The amount of mineral nitrogen in the soil profile 4 weeks after seeding increased with the addition of each of the sources except for the 1% nitrogen organic material which had no effect. Addition of calcium nitrate caused the greatest increase of mineral nitrogen, but did not result in the greatest plant growth because of less efficient nitrogen uptake associated with leaching. At 7 weeks after seeding, nitrogen stress, as indicated by the nitrogen content of the plant tops, had increased more where the 2 and 6% nitrogen organic materials were added than where calcium nitrate was added. This trend was also reflected in changes in the root to shoot ratios, and was the result of roots catching up with leaching nitrate from the calcium nitrate. In the columns treated with organic material, root profiles at 7 weeks after seeding showed enhanced growth at the surface, where mineralization of the added materials was occurring. Where calcium nitrate was added, a bulge in the root profile occurred at depth, associated with the leached nitrate.
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Rosado, Thiago Lopes, Ivoney Gontijo, Marcelo Suzart Almeida, Alberto Chambela Neto e Carla Penha Simon. "PRODUCTION AND TILLERING OF MOMBAÇA GRASS WITH DIFFERENT SOURCES AND LEVELS OF APPLIED NITROGEN". REVISTA ENGENHARIA NA AGRICULTURA - REVENG 24, n. 2 (1 luglio 2016): 139–46. http://dx.doi.org/10.13083/reveng.v24i2.664.
Testo completoAbstract (sommario):
Nitrogen influences numerous physiological and morphological traits of forage grasses, which ultimately interfere directly with production and forage quality. Aimed to study was to evaluate the production of dry matter and the number of tillers of Panicum maximum cv. Mombaça grown with different sources and levels of applied nitrogen. The experiment was conducted at the Federal Institute of the Espírito Santo, Campus of Santa Teresa. The experimental design consisted of a randomised block design with three replicates in a 3 x 6 factorial design and three nitrogenous fertilizers (urea, ammonium sulphate and calcium nitrate), which were applied at six different levels (0, 120, 240, 360, 480 and 600 kg ha-1) during the experimental period, for a total of 54 experimental units. Nitrogen levels were divided into seven applications, and the treatments were applied every 28 days, always after the forage was cut. The results show that Mombaça grass is responsive to nitrogen fertilization, and the response in terms of dry matter production and number of tillers for the same level of nitrogen varies depending on the nitrogen source used. Of the nitrogen sources, calcium nitrate had the best performance for the variables evaluated here. For this nitrogen source, the production of dry matter achieved at the maximum level of nitrogen was 18% and 36% higher than the dry matter achieved with the use of ammonium sulphate and urea, respectively.
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Grieve, Catherine M., James A. Poss, Peter J. Shouse e Christy T. Carter. "Modeling Growth of Matthiola incana in Response to Saline Wastewaters Differing in Nitrogen Level". HortScience 43, n. 6 (ottobre 2008): 1787–93. http://dx.doi.org/10.21273/hortsci.43.6.1787.
Testo completoAbstract (sommario):
The capture and reuse of nutrient-rich greenhouse effluents may be an environmentally sound option for floriculture production, which would conserve fresh water resources and reduce off-site pollution of surface and groundwaters. This study was initiated in 24 outdoor lysimeters to determine effects of salinity and varying concentrations of nitrogen on the growth, yield, and ion relations of stock [Matthiola incana (L.) R. Br.] cultivar Cheerful White. The experiment was a 4 × 4 factorial, partially replicated design with four irrigation water salinities (2, 5, 8, and 11 dS·m−1) and four nitrate concentrations (2.5, 3.6, 5.4, and 7.1 mmol·L−1; N = 35, 50, 75, and 100 ppm). Ammonium nitrogen was included in the nutrient solutions. Stem lengths were measured three times weekly. Measurements at final harvest were stem and inflorescence lengths, stem and floret diameters, number of axillary buds and florets, and shoot and root fresh weights. Time course of stem elongation was quantified as a function of thermal time with a phasic growth model. Salinity significantly delayed initiation of the exponential growth phase, shortened its duration, and reduced the rate of plant development. The overall effect was to delay time to harvest of marketable stems. Although length of the flowering stems decreased with increasing salinity, marketable stems (≈60 cm) were produced in all treatments. Mineral ion relations in the plant tissues were influenced significantly, but independently, by both salinity and nitrogen. Leaf sodium, magnesium, and chlorine concentrations increased with increasing salinity; calcium and potassium decreased. In response to increasing external nitrogen, both potassium and chlorine decreased; sodium increased, whereas calcium and magnesium were unaffected. We conclude that in closed-loop irrigation systems, the nitrogen requirements for stock are low and that growers could minimize costs and limit off-site pollution by reducing nitrogen inputs.
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Bojtor, Csaba, Árpád Illés, Seyed Mohammad Nasir Mousavi, Adrienn Széles, Brigitta Tóth, János Nagy e Csaba L. Marton. "Evaluation of the Nutrient Composition of Maize in Different NPK Fertilizer Levels Based on Multivariate Method Analysis". International Journal of Agronomy 2021 (1 aprile 2021): 1–13. http://dx.doi.org/10.1155/2021/5537549.
Testo completoAbstract (sommario):
One of the critical issues in using micronutrient fertilisers is the comparison of methods and amounts of fertiliser use, which is very important from the aspect of increasing production and economic viewpoint. The aim of this research was to analyse the nutrient composition of different parts of the maize (Zea mays L. FAO 490) during the growing season with six-level nitrogen fertilisation supplies at five phenological stages. The study included essential nutrients as nitrogen (N), phosphorus (P), potassium (K), and sulphur (S) (in first cluster) and calcium (Ca) and magnesium (Mg) (in second cluster) in treatments on different leaf stage. Growth stages have different nutrient demands based on their actual demand. The first cluster included nitrogen and sulphur and the second included calcium and zinc in the NPK treatments on the stalk of plants. Nitrogen and potassium had their maximum effect on the stalk of maize during the growing season. Magnesium and copper were the second most important and desirable factors during the different growth stages and treatments in relation to the stalk. Nitrogen and calcium had their maximum impact during the yield formation stage and nitrogen and phosphorus had their most desirable effect during the grain filling stage. The effect of nitrogen on the quantitative and qualitative properties of maize showed that nitrogen increases the production of dry matter, grain yield, and its components. The maximum amount of absorption in the plants occurs before the accumulation of applied fertiliser, which is the prelude to the production of maximum biomass.
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Conley, M. Elizabeth, e Ellen T. Paparozzi. "Macroand Micronutrient Levels Associated with Nitrogen and Sulfur Applications to `Freedom Red' Poinsettia". HortScience 32, n. 3 (giugno 1997): 444E—445. http://dx.doi.org/10.21273/hortsci.32.3.444e.
Testo completoAbstract (sommario):
In order to understand the effects of reduced nitrogen and sulfur on overall poinsettia plant growth and development, experiments were run to determine the relationship, if any, between nitrogen and sulfur applied and other macroand micronutrients. Cuttings of `Freedom Red' (Euphorbia pulcherrima Willd. ex Klotzsch) were grown vegetatively in a peat:perlite:vermiculite mix during the fall and spring. Three levels of sulfur (0, 12.5, 25 ppm) were applied in combination with four levels of nitrogen (50, 100, 200, 275 ppm). The experimental design was a randomized complete block. Leaf samples were analyzed using LECO for nitrogen and ICP-ES for sulfur. X-ray fluorescence was used to determine trends in the nutrient concentration of other macronutrients and micronutrients. Nutrient analyses indicated that all nutrients were present in sufficient quantities. Leaf concentrations of nitrogen, sulfur, potassium, and copper were distinctly higher in spring and fall, while phosphorus, calcium, magnesium, and iron concentrations were higher in fall. The typically subtle effects of sulfur were most obvious in magnesium and calcium leaf concentrations. Phosphorus and calcium concentrations increased at lower levels of applied nitrogen. Concentrations of boron, copper, and manganese also increased strikingly at lower levels of applied nitrogen. Apparently when levels of nitrogen less than 200 ppm are applied, micronutrient uptake increases, suggesting the potential of either luxury consumption or possible toxic effects if too little nitrogen is supplied.
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SWIATKIEWICZ, S., J. KORELESKI e A. ARCZEWSKA-WLOSEK. "Egg performance, egg quality, and nutrient utilization in laying hens fed diets with different levels of rapeseed expeller cake". Agricultural and Food Science 19, n. 3 (4 dicembre 2008): 233. http://dx.doi.org/10.2137/145960610792912594.
Testo completoAbstract (sommario):
The aim of this study was to evaluate the effect of different levels of rapeseed expeller cake (RC) in the diet of laying hens on egg performance, egg quality, retention and excretion of nitrogen, calcium and phosphorus, and metabolizability of energy. The experiment was carried out with 72 Bovans Brown hens, from 28 to 53 weeks of age. Experimental treatment consisted of four isonitrogenous and isocaloric corn-soybean diets (as calculated: 17% crude protein, 11.6 MJ/kg metabolizable energy, 0.81% lysine, 0.36% methionine, 3.60% calcium and 0.37% available phosphorus), containing 0, 4, 6 or 8% RC. The RC used was produced from double zero rapeseed and contained 29.3% crude protein, 17.4% crude fat, 10.8% crude fibre, 0.63% calcium, 0.97% phosphorus, 1.91% lysine and 0.84% methionine. During the experimental period, the dietary level of RC had no significant effects on egg performance and egg quality parameters. Boiled eggs from hens fed a diet with 8% RC were characterized by an inferior flavour to those from other groups. There were no treatment effects on nitrogen balance or metabolizability of energy, though the highest dietary level of RC negatively affected retention and excretion of calcium and phosphorus.;
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Li, Y., T. Wang, J. Li e Y. Ao. "Effect of phosphorus on celery growth and nutrient uptake under different calcium and magnesium levels in substrate culture". Horticultural Science 37, No. 3 (14 luglio 2010): 99–108. http://dx.doi.org/10.17221/81/2009-hortsci.
Testo completoAbstract (sommario):
A greenhouse pot experiment was performed to study the effect of phosphorus (P) on celery (Apium graveolens L.) growth, quality and nutrient uptake under different calcium (Ca) and magnesium (Mg) levels in substrate culture. Results showed that there were significant interactions between P and the level of Ca and Mg in the growing media. Celery above-ground fresh weight, total dry biomass, leaf area, and P, Ca and Mg concentrations in celery leaves significantly increased from 0 to 124 mg/l P application. The opposite trends were observed for root/shoot ratio, leaf chlorophyll, carotenoids, soluble protein, soluble sugar, vitamin C, and nitrogen and potassium concentration in celery leaves. Medium Ca and Mg level (Ca 320 and Mg 192 mg/l) significantly increased celery above-ground fresh weight, total dry biomass and leaf area compared to low (Ca 160 and Mg 96 mg/l) and high (Ca 640 and Mg 384 mg/l) levels. This study suggested that 124–248 mg/l P applications under medium Ca and Mg level were appropriate for celery nutritional requirements.
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Pavlíková, D., M. Neuberg, E. Žižková, V. Motyka e M. Pavlík. " Interactions between nitrogen nutrition and phytohormone levels in Festulolium plants". Plant, Soil and Environment 58, No. 8 (21 agosto 2012): 367–72. http://dx.doi.org/10.17221/367/2012-pse.
Testo completoAbstract (sommario):
This study aims to reveal and to compare effect of two various systems of nitrogen nutrition, namely injection and sidedress application, on the levels of NO3– and phytohormones (cytokinins, abscisic acid (ABA), indole-3-acetic acid (IAA)) in Festulolium plants. Calcium nitrate (CN) or ammonium sulphate (AS) were used as N source in the pot experiment. The yield of Festulolium above and below ground biomass was more substantially enhanced after sidedress application of both AS or CN in comparison with injection application. The levels of endogenous cytokinins peaked 5 days after application regardless the form of N source and the method of application. The increased concentration of endogenous cytokinins as well as the enhanced content of selected free amino acid suggest that N applied sidedress can maintain better distribution patterns of nutrients and provide improved conditions for growth and nitrogen uptake. The nitrogen application affected ABA concentrations on all tested treatments. The correlation between NO3– and ABA concentrations ranged from 0.77 to 0.89. A significant IAA increase was recorded in plants after ammonium nitrogen sidedress application and it was confirmed that applications of nitrate reduced IAA concentration (correlation between NO3– and IAA for AS treatment R2 = 0.77–0.94).
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Santos-de-Souza, Daniele, Lígia Fátima Lima-Calixto, Marina Jorge-de-Lemos, Túlio Leite-Reis, Carlos Augusto Oliveira, Édson José Fassani, Maria Clara Do-Coutto-Prado-Valladares e Felipe Dilelis De Resende Sousa. "Inclusion of kaolin in the feed of Japanese quails during the production phase". Revista Colombiana de Ciencias Pecuarias 32, n. 4 (7 novembre 2019): 274–84. http://dx.doi.org/10.17533/udea.rccp.v32n4a03.
Testo completoAbstract (sommario):
Background: Kaolin may improve quail performance by maintaining intestinal integrity and improving nutrient absorption. Objective: To evaluate the overall performance, egg quality, moisture, nitrogen and calcium content in the excreta, intestinal morphology and financial analysis of kaolin in Japanese quail feed during the production phase. Methods: A total of 192 Japanese quails, distributed in a completely randomized design with four treatments and six repetitions with eight birds each, were used. Kaolin levels added to the diet were 0, 1.5, 3.0, and 4.5%. Results: Kaolin reduced feed consumption. Additionally, egg production, feed conversion and viability increased. Moisture, nitrogen and calcium in the excreta decreased. Height and width of the intestinal villi increased with increasing levels of kaolin in the diet. Kaolin had no effect on egg quality. Inclusion level of 1.5% kaolin allowed for greater economic gains. Conclusion: Kaolin improved performance, intestinal morphology, and reduced the moisture, nitrogen and calcium contents in the excreta. Egg quality remained unchanged with the addition of kaolin, and the best economic response resulted with the addition 1.5% kaolin.
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Diomandé, L. B., G. R. Soro, S. Soro e Et Yao Kouamé A. "CHEMICAL SOIL FERTILITY DIAGNOSIS FOR COTTON CROPPING IN NORTHERN COTE D'IVOIRE". International Journal of Research -GRANTHAALAYAH 9, n. 8 (31 agosto 2021): 27–34. http://dx.doi.org/10.29121/granthaalayah.v9.i8.2021.4130.
Testo completoAbstract (sommario):
The work was conducted in the north of Cote d’Ivoire, central pivot cotton production savannah area, to make the diagnosis of soil fertility for cotton cropping. Cotton cropping, the mainstay of the savannah's economy, suffered from low productivity in relation to the soils chemical properties. Prior cultivation, soils samples were collected at a depth of 0 to 30 cm, collecting 32 simple samples to generate a complete sample. The samples were sent to the soil laboratory to measure the pH unities, CEC, nitrogen, phosphorus, potassium, calcium, magnesium, sodium, iron, zinc, copper and manganese contents. In order to facilitate the interpretation of analysis results, the nutrients critical level recommended for optimum production of cotton were used. Results showed that soils had pH ranging from 4.4 to 6.4. On the other hand, the need to add nitrogen, magnesium and phosphorus to the soils and to augment the low carbon, calcium and potassium content. There is the need to search for fertilizer formulations with nitrogen, magnesium phosphorus and calcium for the Cote d'Ivoire cotton belt.
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TAKAHASHI, NORIHIRO, TETSUO SHOJI, KEISUKE MATSUBARA, HIROFUMI HITOMI, MAYUKO HASHIMOTO, HIDEYASU KIYOMOTO, KOICHI UCHIDA et al. "Effect of Histamine H2-Receptor Antagonist on the Phosphorus-Binding Abilities of Calcium Carbonate and Calcium Lactate in Hemodialysis Patients". Journal of the American Society of Nephrology 10, n. 5 (maggio 1999): 1090–94. http://dx.doi.org/10.1681/asn.v1051090.
Testo completoAbstract (sommario):
Abstract. The effect of histamine H2-receptor antagonist (famotidine) on the phosphorus-binding abilities of calcium carbonate and calcium lactate were examined in 13 chronic hemodialysis patients. In seven patients receiving calcium carbonate, famotidine (20 mg/d) was given because of gastroduodenal disorders, and calcium carbonate was replaced with calcium lactate as a phosphorus binder after 4 wk of treatment with famotidine. With the 4-wk administration of famotidine accompanied by calcium carbonate, the serum phosphorus level increased from 6.3 ± 0.9 to 7.1 ± 0.5 mg/dl (P < 0.05). However, with the substitution of calcium lactate, the serum phosphorus level decreased significantly when compared to that before substitution (6.3 ± 0.2 and 6.0 ± 0.9 mg/dl after 4 and 8 wk of substitution, respectively), despite continued administration of famotidine. Serum calcium, creatinine, alkaline phosphatase, high sensitive parathyroid hormone, blood urea nitrogen, arterial blood pH, and bicarbonate were not significantly altered during the trial period. In six control patients treated with calcium carbonate alone, there were no statistical changes in serum calcium and phosphorus levels after substitution of calcium lactate for calcium carbonate. These results suggest that famotidine significantly affects the phosphorus-binding ability of calcium carbonate, but not that of calcium lactate. A careful observation of changes in the serum phosphorus level should be required in hemodialysis patients receiving calcium carbonate and histamine H2-receptor antagonists. Calcium lactate may be useful as a phosphorus binder in such hemodialysis patients.
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Nurdogan, Yakup, e William J. Oswald. "Enhanced nutrient removal in high-rate ponds". Water Science and Technology 31, n. 12 (1 giugno 1995): 33–43. http://dx.doi.org/10.2166/wst.1995.0453.
Testo completoAbstract (sommario):
High-rate ponding (HRP) processes have evolved from conventional oxidation ponds and could play an important role in the treatment of organic wastewaters in sunbelt communities requiring tertiary treatment. HRP systems are very efficient in removing biochemical oxygen demand, nitrogen, and phosphorus. Mineralized nitrogen is removed by algal uptake of ammonium ion (NH4+) and out-gassing of ammonia (NH3). High daytime pH generated in the pond due to algal uptake of bicarbonate shifts the equilibrium in favor of NH3. There are also two mechanisms for phosphorus removal in an HRP; algal uptake and chemical precipitation. Phosphorus uptake by algae is lower than nitrogen uptake because the nitrogen content of algae is approximately ten times more than the phosphorus content, which is approximately one percent of the 100 to 300 mg/l algal dry weights in an HRP. If sewage contains 10 mg/l of phosphorus, algal phosphorus uptake would be only 1 to 3 mg/l. Precipitation of phosphates with polyvalent cations such as calcium and magnesium also occurs in a HRP due to the high pH. This precipitation is sometimes called “autoflocculation”, which is often incomplete due to insufficient calcium and magnesium concentrations in the wastewater. In the case of Richmond, California, where the studies were conducted, the sewage has low magnesium and very low calcium concentrations. Enhancement of calcium and magnesium deficient autoflocculation was studied by adding 20 to 80 mg/l of freshly slaked lime to the pond during the continuous paddle wheel mixing. This simple procedure improved phosphorus, nitrogen and algae removal efficiencies to a level greater than 90%.
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Ozgen, Senay, Christopher Gunter, Bjorn Karlsson e Jiwan Palta. "590 Supplemental Application of Calcium and Nitrogen Improves Internal Quality of `Russet Burbank' Potatoes". HortScience 35, n. 3 (giugno 2000): 498C—498. http://dx.doi.org/10.21273/hortsci.35.3.498c.
Testo completoAbstract (sommario):
Potato tuber tissue is calcium-deficient. Consequently, increasing Ca concentration is desirable to improve tuber quality. The purpose of the present study was to determine the influence of supplemental Ca and N fertilization on internal quality of potato. Three products (calcium nitrate, calcium chloride, and gypsum) were used to increase tuber calcium concentration. We tested combinations of both soluble sources of calcium and gypsum. Each treatment had five replications and received same total amount of N, supplied either from ammonium nitrate, liquid N (UAN: 50% urea + 50% ammonium nitrate) and calcium nitrate or combination of these sources (at rate of 225 kg·ha–1). The total Ca was applied at the rate of 168 kg·ha–1. Application of N at emergence and hilling (nonsplit) was compared to split application of N and Ca at hilling, 2, 4, and 6 weeks after hilling. At harvest, ≈100 tubers from each replication were cut in half along longitudinal axis and visually inspected for internal defect in both years. Application of Ca, especially in split schedule and from soluble sources, significantly increased tuber tissue Ca concentration. In 1998, the incidences of hollow heart (HH) and internal brown spots (IBS) were very low. The treatment containing calcium nitrate and calcium chloride combination produced the lowest total defects, whereas application of gypsum was not effective at reducing defects. In 1999, application of all Ca sources including gypsum, reduced HH and IBS. Data from these studies suggest that tuber calcium level is increased by field applications of moderate amount of Ca and tuber quality is impacted by N and Ca application. Furthermore, seasonal climatic variations appear to have dramatic influence on the incidence of internal defects in potato tubers.
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Le Rü, B., J. P. Diangana e N. Beringar. "Effects of nitrogen and calcium on the level of resistance of cassava to the mealybug P. manihoti". International Journal of Tropical Insect Science 15, n. 01 (febbraio 1994): 87–96. http://dx.doi.org/10.1017/s1742758400016805.
Testo completo
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Kubik-Dobosz, Genowefa. "The influence of potassium and calcium ions on nitrogen metabolism of cucumber seedlings". Acta Societatis Botanicorum Poloniae 50, n. 3 (2014): 437–47. http://dx.doi.org/10.5586/asbp.1981.067.
Testo completoAbstract (sommario):
It was found that K<sup>+</sup> or Ca<sup>2+</sup> deficiency in a nitrate or ammonium medium increased the amount of accumulated total and non-protein nitrogen in some organs of cucumber seedlings, as also caused changes in accumulated potassium and calcium. Lack of K<sup>+</sup> or Ca<sup>2+</sup> in a medium which did not contain nitrogen led to an increased level of glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in the cotyledons and roots of cucumbers. Similar changes in the activity of these enzymes were noted in certain organs of seedlings growing in nitrate or ammonium medium with decreased K<sup>+</sup> or Ca<sup>2+</sup> contents, although the magnitude of these changes depended upon the applied dosage of these cations, the form of mineral nitrogen, developmental phase of plants and the plant organ dealt with.
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Kleinhenz, Matthew D., Jiwan P. Palta, Christopher C. Gunter e Keith A. Kelling. "Impact of Source and Timing of Calcium and Nitrogen Applications on `Atlantic' Potato Tuber Calcium Concentrations and Internal Quality". Journal of the American Society for Horticultural Science 124, n. 5 (settembre 1999): 498–506. http://dx.doi.org/10.21273/jashs.124.5.498.
Testo completoAbstract (sommario):
Three Ca sources and two application schedules were compared for their effectiveness for increasing tissue Ca concentrations in 170 to 284 g field-grown tubers of `Atlantic' potato (Solanum tuberosum L.). Additional observations were made of internal physiological defects. Paired measures of tissue (periderm and nonperiderm) Ca concentration and internal quality (±hollow heart, ±internal brown spot) were made on individual tubers produced in plots fertilized with N at 224 kg·ha-1 and Ca at either 0 or 168 kg·ha-1, supplied from either gypsum, calcium nitrate or NHIB (9N-0P-0K-11Ca, a commercial formulation of urea and CaCl2). Application of N and Ca at emergence and hilling (nonsplit) was compared to application at emergence, hilling, and 4 and 8 weeks after hilling (split). Tuber yield and grade were unaffected by treatments. Split Ca application (from either calcium nitrate or NHIB) increased mean tuber nonperiderm tissue Ca concentrations and the percentage of tubers with an elevated Ca concentration in both years compared with non-Ca-supplemented controls. Split Ca application also resulted in greater increases in Ca in nonperiderm tissue than nonsplit Ca application in 1994. Although the correlation coefficient between Ca level in periderm and nonperiderm tissue of >400 individual tubers was highly significant in both study years, linear regression analyses suggested the Ca level in the two tissues were poorly related. Split application was associated with a 37% reduction in the incidence of internal tuber defects, relative to nonsplit application in 1994. Calcium application did not affect tuber internal quality based on means analysis, but chi-square analysis suggested that Ca concentration and internal quality of individual tubers may be related. The incidence of internal defects was 16.4% in tubers with nonperiderm tissue Ca >100 μg·g-1 dry weight compared to 10.6% in tubers with nonperiderm tissue Ca >100 μg·g-1 dry weight. These data suggest that 1) it is feasible to increase tuber Ca levels by field applications of moderate amounts of Ca, 2) tuber quality is impacted by N and Ca application schedule, and 3) Ca concentrations in tuber periderm and nonperiderm tissues may be controlled independently.
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Heinrichs, Reges, Fernanda Grecco Grano, Leda Gobbo de Freitas Bueno, Cecílio Viega Soares Filho, Jailson Lara Fagundes, Melina Daniel Rebonatti e Katia de Oliveira. "Brachiaria sp yield and nutrient contents after nitrogen and sulphur fertilization". Revista Brasileira de Ciência do Solo 37, n. 4 (agosto 2013): 997–1003. http://dx.doi.org/10.1590/s0100-06832013000400017.
Testo completoAbstract (sommario):
Among the production factors, adequate fertilization is an important tool to raise the productivity of pastoral systems and consequently increase the share of Brazil in the supply chain of primary agricultural products at the global level. The objective of this study was to evaluate the interaction of nitrogen and sulfur fertilization in BRACHIARIA DECUMBENS: Stapf. The experiment in pots with Dystrophic Oxisol was evaluated in a completely randomized design with four replications in a 5 x 3 factorial arrangement, involving five N doses (0, 100, 200, 400, and 800 mg dm-3) in the form of ammonium nitrate and three S doses (0, 20 and 80 mg dm-3) in the form of calcium sulfate, with a total of 15 treatments. In the treatments with low S dose, calcium was provided as calcium chloride, to ensure a homogeneous Ca supply in all treatments. The results showed that the tiller production and dry weight of green leaves and of stems + sheaths and total dry weight were favored by the combination of N and S fertilizer, while the proportion of dry leaves was reduced. Nitrogen fertilization raised the N contents in green leaves and stems + sheaths and reduced K contents in fresh and dry leaves. The response to S rates in the N content of green leaves was quadratic.
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Balla Kovács, Andrea, Anita Szabó e Emese Bartáné Szabó. "Studies of the influences of different N fertilizers and Microbion UNC bacterial fertilizer on the nutrient content of soil". Acta Agraria Debreceniensis, n. I (5 ottobre 2010): 134–40. http://dx.doi.org/10.34101/actaagrar/i/8391.
Testo completoAbstract (sommario):
A field experiment was conducted to examine the effects of different nitrogen fertilizers in combination with bacterial fertilizer onnutrient uptake of horseradish and plant available nutrients of the soil. Three different N fertilizers, ammonium-nitrate, urea and calciumnitrate(116 kg ha-1 N) in combination with Microbion UNC bacterial fertilizer (2 kg ha-1) were applied as treatments in a randomizedcomplete block design in three replications. In this paper we presented the results of soil measurements. The soil of the experimental areawas chernozem with medium sufficiency level of N and P and poor level of K.Our main results:The amount of 0.01M CaCl2 soluble inorganic nitrogen fractions, NO3--N and NH4+-N and also the quantity of soluble organic-N werealmost the same in the soil. N fertilizers significantly increased all the soluble N fractions. The amount of NO3--N increased to the greatestextent and the increase of organic N was the slightest. We measured the largest CaCl2 soluble NO3- -N and total-N contents in the plotstreated with ammonium-nitrate, the largest NH4+-N in the plots treated with calcium-nitrate and the largest organic-N fraction in plotstreated with urea.Bacterial inoculation also increased both soluble inorganic nitrogen forms and also total-N content of soil compared to the control. Inthe case of combined (artificial and bacterial fertilizer) treatments we measured lower NO3--N, organic-N and total-N compared to thevalues of plots having only nitrogen fertilizer treatments. On the contrary in the plots with combined treatments the CaCl2 soluble NH4+-Ncontent of soil in more cases were higher than that of values with artificial fertilizer treatment.As a function of calcium-nitrate application increased AL-P2O5 and AL-K2O values were measured compared to control. MicrobionUNC supplement of calcium nitrate yielded also increase in AL-P2O5 and AL-K2O values, till then supplement of ammonium-nitrate fertilizeryielded a decrease in these values compared to the control.All nitrogen fertilizers resulted in a significant decrease in AL-Mg content of soil compared to the control. Nevertheless bacterialfertilizer increased AL-Mg values in any cases.
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Tooley, Joshua A., Harley Naumann e David G. Mendoza-Cozatl. "PSVII-18 Nitrogen fertilization affects leaf-level sodium and potassium concentration in tall fescue pasture". Journal of Animal Science 97, Supplement_3 (dicembre 2019): 301. http://dx.doi.org/10.1093/jas/skz258.608.
Testo completoAbstract (sommario):
Abstract Optimizing mineral supplementation is critical to maximizing production in a forage-based beef production system. The effect of nitrogen fertilization on mineral accumulation in tall fescue (TF) is not well understood. We evaluated the differences in mineral composition in nitrogen fertilized (TF+N) and unfertilized (TF-N) tall fescue pastures. The experiment was conducted at the University of Missouri Forage Systems Research Center during 2017 and 2018. A randomized complete block design was arranged in novel-endophyte TF pastures. All pastures were mechanically harvested in May. Nitrogen was applied to TF+N in June and again in August (45 kg ha-1 and 90 kg ha-1, respectively). Treatments were rotationally grazed from July to November using yearling cattle. Randomly selected 10 m2 strips were harvested biweekly and 300 g subsamples were dried. Nitric acid digestion was performed followed by ICP-MS to determine mineral content. Data were normalized using rank transformation and analyzed by treatment and month. Analysis of variance was conducted using PROC GLIMMIX (SAS 9.4); slice command was used to determine interactions within month by treatment and within treatment by month. Calcium and magnesium concentration decreased throughout the season with the lowest concentrations observed in both treatments during November (P = 0.0043 and P = 0.0007, respectively). Greater potassium concentrations were observed in June compared to November in both treatments (P < 0.0334). We observed a within month by treatment interaction for sodium. Nitrogen fertilization resulted in greater sodium concentration in all months from August to November compared to TF-N (P < 0.0074). Greater sodium concentrations resulted in decreased K:Na ratios during September, October, and November in TF+N (P = 0.0013, P = 0.0036, and P = 0.0024, respectively). Our results suggest nitrogen fertilization reduced K:Na ratio in TF pastures, which could negatively affect magnesium absorption in recticulo-rumen.
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Lavon, Ruth, Raphael Salomon e Eliezer E. Goldschmidt. "Effect of Potassium, Magnesium, and Calcium Deficiencies on Nitrogen Constituents and Chloroplast Components in Citrus Leaves". Journal of the American Society for Horticultural Science 124, n. 2 (marzo 1999): 158–62. http://dx.doi.org/10.21273/jashs.124.2.158.
Testo completoAbstract (sommario):
The chlorotic appearance of mineral-deficient citrus leaves presumably reflects degradative changes in chloroplast components, most of which have nitrogen as a principal constituent. To examine this assumption the size of some major nitrogen pools, the SDS-PAGE pattern of soluble and chloroplast membranal proteins, and the activities of nitrate reductase and ribulose bisphosphate carboxylase (RuBPcase) were determined in leaves of rough-lemon (Citrus volkameriana Ten. & Pasq) plants grown hydroponically for 3 to 10 months under K, Mg, and Ca deficiencies. Plants grown under minerally deficient conditions produced less biomass. Leaves developing under K, Mg, and Ca-deficient conditions had significantly reduced concentrations of the respective elements. Chlorophyll levels of the chlorotic Mg and Ca-deficient leaves were lower than those of control leaves but chlorophyll a/b ratios were not markedly different. Calcium deficiency caused significant decreases in total nitrogen, nitrates, and the free amino acid pool. Proline which is the major component of the free amino acid pool decreased by 82.5%. Calcium-deficient leaves had significantly lower nitrate reductase and RuBPcase activities. The level of RuBPcase holoenzyme and its subunits were also reduced. Protein levels of K, Mg, and Ca-deficient leaves were not significantly altered. The SDS-PAGE patterns of soluble and chloroplast membranal proteins did not reveal major qualitative changes. In conclusion, the data do not demonstrate a general close link between chlorosis of minerally deficient citrus leaves and nitrogen metabolism. Calcium deficiency seems to specifically interfere with early stages of nitrogen assimilation and free amino acid accumulation but the metabolic integrity of the leaf is apparently maintained even under severe nutritional stress conditions.
22
Pintar, J., B. Homen, K. Gazić, Z. Janječić, M. Sikirić e T. Černy. "Effects of supplemental phytase on nutrient excretion and retention in broilers fed different cereal based diets". Czech Journal of Animal Science 50, No. 1 (5 dicembre 2011): 40–46. http://dx.doi.org/10.17221/3993-cjas.
Testo completoAbstract (sommario):
A 21-day experiment with day-old broilers was conducted in order to assess the effect of phytase supplementation to different cereals-soybean meal based diets on nitrogen, calcium, total and phytate phosphorus excretion and retention. Diets were formulated to contain 4 different cereals (maize, wheat, triticale and barley), 2 levels of dietary calcium (0.6 and 1.0%) and 3 levels of supplemental phytase (0, 500 and 1 000 PU/kg). Nutrient intake, excretion and retention were determined in the first three days of the 2nd and 3rd week of trial. The increasing phytase level resulted in reducing phytate phosphorus excretion and increasing its retention. Significant differences were obtained only in the 2nd week (excretion P < 0.024 and retention P < 0.044). Phytase supplementation significantly influenced total phosphorus excretion in the 3rd week (P < 0.048) and retention in the 2nd week (P < 0.015). The effects of 500 and 1 000 PU/kg were not statistically different from each other. No significant influence of phytase supplementation on nitrogen and calcium excretion and retention was observed.
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Ryan, M. H., D. R. Small e J. E. Ash. "Phosphorus controls the level of colonisation by arbuscular mycorrhizal fungi in conventional and biodynamic irrigated dairy pastures". Australian Journal of Experimental Agriculture 40, n. 5 (2000): 663. http://dx.doi.org/10.1071/ea99005.
Testo completoAbstract (sommario):
The broad-scale factors determining the level of colonisation by arbuscular mycorrhizal fungi in irrigated permanent pasture were investigated using 10 pairs of dairy farms located in northern Victoria, Australia. Each pair consisted of adjacent farms, one under conventional management and the other under biodynamic management. Significant quantities of fertilisers were applied only to the conventional pastures and this was the major difference in inputs between the 2 management systems. Colonisation by arbuscular mycorrhizal fungi of white clover (Trifolium repens L.), perennial ryegrass (Lolium perenne L.) and paspalum (Paspalum dilatatum Poir.) was lower in the conventionally managed pastures than in the biodynamic pastures. On all farms, clover was more highly colonised than the grasses. The level of colonisation in clover exhibited a strong negative relationship with the concentration of phosphorus in the pasture shoots and a weak negative correlation with soil-extractable phosphorus. Similar relationships were evident for the grasses, but these were not as strong. Soil pH, soil organic carbon and the concentration of other soil nutrients (Kjeldahl nitrogen, sulfate, EDTA copper, EDTA zinc, chlorine, and exchangeable potassium, sodium, calcium and magnesium) and pasture shoot nutrients (chlorine, sodium, potassium, calcium, magnesium, manganese, copper, zinc, iron, nitrogen, sulfur and boron) could not account for differences in colonisation levels. On 3 farm pairs, colonisation levels by arbuscular mycorrhizal fungi were monitored over 3.5 years. Colonisation did not vary seasonally. It is concluded that phosphorus levels and host plant will be the major determinants of colonisation levels by arbuscular mycorrhizal fungi in perennial irrigated pasture-based agricultural systems.
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Firoz, ZA, KM Nasiruddin e MF Mondal. "Effect of Different Hedgerow Species and Nitrogen Level on the Soil Properties and Yield of Okra (Abelmoschus esculentus L. Moench)". Bangladesh Journal of Agricultural Research 37, n. 1 (11 luglio 2012): 159–69. http://dx.doi.org/10.3329/bjar.v37i1.11190.
Testo completoAbstract (sommario):
Khagrachari from June 2002 to November 2004 to find out the effect of hedgerow species (Ipil-ipil, Indigofera, Pigeon pea , Pineapple with control) and different nitrogen levels (50, 75, and 100% recommended dose of N) on the soil properties and yield of okra in hill slope condition during the rainy season. Different soil properties were affected by hedgerow species and N level with okra crop. In maximum cases, Indigofera with 100% N showed better performance. The highest pH value 6.0, total nitrogen content 0.84, available phosphorus 4.4, exchangeable calcium 1.27 meq/100g, exchangeable sulphur 12.8 meq/100g, and CEC 21.5 were recorded from Indigofera with 100% N. The most satisfactory okra yield 15.05 t/ha was in Indigofera+100% N that was statistically at par with Indigofera+75% N. DOI: http://dx.doi.org/10.3329/bjar.v37i1.11190 Bangladesh J. Agril. Res. 37(1): 159-169, March 2012
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Chohura, Piotr, e Eugeniusz Kołota. "Effect of Nitrogen Fertilization on the Yield and Quality of Field-grown Leaf Lettuce for Spring Harvest". Vegetable Crops Research Bulletin 71, n. 1 (1 gennaio 2009): 41–49. http://dx.doi.org/10.2478/v10032-009-0025-8.
Testo completoAbstract (sommario):
Effect of Nitrogen Fertilization on the Yield and Quality of Field-grown Leaf Lettuce for Spring HarvestTwo field experiments with leaf lettuce were carried out in 2006-2008. Each of them was set up in a random sub-block design in 3 replications and a two-factorial system. The first factor represented different nitrogen doses that were used to obtain the required N level in the soil prior to planting the seedlings, the levels being: 50, 100 and 150 mg N·dm-3. The second factor incorporated 4 nitrogenous fertilizers which were different in terms of chemical composition, and, more importantly, contained different nitrogen forms for introduction to the soil: ammonium nitrate 34% N-[NH4NO3], calcium nitrate 15.5% N-[Ca(NO3)2xH2O+NH4NO3], ammonium sulphate 20.0% N-[(NH4)2SO4], and ENTEC 26% N-[NH4NO3+(NH4)2SO4+0.8% DMPP]. Two varieties of leaf lettuce were used: Casabella (of the type Lollo Bionda) with green leaves, and Klausia (of the type Lollo Rosa) with red leaves. The best sources of nitrogen for the lettuce plants were the fertilizers ENTEC 26 and ammonium nitrate, which in contrast to calcium nitrate and ammonium sulphate made it possible to obtain significantly higher yields of lettuce. Irrespective of the kind of the nitrogenous fertilizer used, increasing the concentration of nitrogen in the soil from 50 mg N·dm-3to 100 mg N·dm-3resulted in a significant increase in the marketable yield of lettuce. At 150 mg N·dm-3this yield remained at a level similar to that at 100 mg N·dm-3. The lettuce fertilized with ammonium sulphate was marked by the lowest mean nitrate content in the leaves before harvest. The use of gradually higher doses of nitrogen resulted in a reduced dry weight content and lower levels of total and reducing sugars in lettuce leaves. With respect to yield size and quality, the recommended concentration of nitrogen in the soil for leaf lettuce should not exceed 100 mg N·dm-3.
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Neghab, Masoud, Ahmad Mirzaei, Hamed Jalilian, Mehdi Jahangiri, Jafar Zahedi e Saeed Yousefinejad. "Effects of Low-level Occupational Exposure to Ammonia on Hematological Parameters and Kidney Function". International Journal of Occupational and Environmental Medicine 10, n. 2 (1 maggio 2019): 80–88. http://dx.doi.org/10.15171/ijoem.2019.1527.
Testo completoAbstract (sommario):
Background: Many workers, particularly those working in manufacture of fertilizers, explosives, rubber, pesticides, textiles, and employees of petrochemical industries are exposed to ammonia in their workplaces. Toxic responses of hematopoietic system and kidney following occupational exposure to this chemical have not been thoroughly investigated. Objective: To determine the relationship between long-term occupational exposure to low levels of ammonia and hematological parameters and kidney function. Methods: In this cross-sectional study, 119 randomly selected, male petrochemical workers and 131 office employees (comparison group) were examined. Urine and blood samples were taken from all participants for urinalysis, complete blood count (CBC), serum calcium level, and blood urea nitrogen (BUN) and plasma creatinine. Personal, environmental, and peak ammonia exposure were also measured. Results: The median personal, environmental, and peak occupational exposure to ammonia were 0.23, 0.16, and 65.50 mg/m3, respectively, among the exposed group. No significant difference was observed between the exposed and unexposed participants in terms of hematological parameters and urinalysis. Conversely, calcium and BUN, while within the normal range, were significantly higher in the exposed than in the comparison group. Conclusion: Occupational exposure to low atmospheric concentrations of ammonia was associated with subtle, sub-clinical, pre-pathologic changes in kidney function. Possible longterm consequences and ramifications of these effects require further investigation.
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Varley, Patrick F., Catherine McCarney, James J. Callan e John V. O'Doherty. "Effect of dietary mineral level and inulin inclusion on phosphorus, calcium and nitrogen utilisation, intestinal microflora and bone development". Journal of the Science of Food and Agriculture 90, n. 14 (26 luglio 2010): 2447–54. http://dx.doi.org/10.1002/jsfa.4105.
Testo completo
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Shalyuta, B. V., e E. V. Kostitskaya. "The Yield of Silphium Perfoliatum L. Depending on the Conditions of Cultivation". Agricultural Engineering 22, n. 2 (1 luglio 2018): 91–97. http://dx.doi.org/10.1515/agriceng-2018-0019.
Testo completoAbstract (sommario):
AbstractThe article presents the results of two-year studies on the influence of the method of sowing and the level of nitrogen application on the yield of seeds of Silphium perfoliatum L. − a new fodder crop for the conditions of Belarus. Silphium is precious for the nutritive value of green mass. According to the literature sources, dry matter contains 16-28% of protein, more than 60% of nitrogen-free extractives, 13-23% of sugars, high content of mineral substances, a small amount of fiber, adequate calcium and phosphorus, carotene, vitamin C. Mineral composition of Silphium contains 17.6% of dry matter, including 152.3 mg·kg−1 of ash. Macro elements: calcium – 18.1, phosphorus − 2.55, manganese – 4.48, potassium – 24.03, sodium – 0.40, sulphur – 0.40 mg· kg−1 of mg· kg−1 of dry matter. The mass of 1000 seeds was from 23.7 to 25.5 g. The seed germination was good and varied from 75% to 84%. It has been established that the best way to sow the Silphium is planting seedlings according to the 70x30 scheme. This option ensured the yield of seeds of 3.6 and 3.7 c/ha. The applying of increased doses of nitrogen fertilizers N90 and N120 and sowing seeds ensured the yield of seeds ranging from 3,6 to 3,9 c·ha−1.
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Urrea-López, Rafael, Rocío I. Díaz de la Garza e Juan I. Valiente-Banuet. "Effects of Substrate Salinity and Nutrient Levels on Physiological Response, Yield, and Fruit Quality of Habanero Pepper". HortScience 49, n. 6 (giugno 2014): 812–18. http://dx.doi.org/10.21273/hortsci.49.6.812.
Testo completoAbstract (sommario):
Although habanero peppers (Capsicum chinense, Jacq.) are highly appreciated as a result of their organoleptic and pungency properties, the crop faces edaphic stresses throughout Mexico. A study was conducted to determine how the photosynthetic parameters, vegetative growth, yield, and fruit quality of the plant change in response to suboptimal conditions in the substrate. Habanero plants were grown in an inert substrate (perlite) and exposed to increased salinity levels (4 and 7 dS·m−1) and reduced nitrogen and phosphorus conditions. Plants grown with a Hoagland-based solution were used as controls. High salinity conditions reduced the light-saturated photosynthetic rates (64% of the control) but did not compromise yield or fruit quality. This effect was possibly the result of the addition of Ca2+, which reduced salinity-induced calcium deficiency. Although comparable low nitrogen levels in previous studies were shown to cause a severe reduction in plant viability, in our study, low nitrogen reduced the light-saturated photosynthetic rates (47% of the control) and shoot:root ratio (67% of the control) but did not significantly affect yield or fruit quality. Low nitrogen and 7-dS·m−1 treatments increased fructose and glucose content (increases of 27% and 21%, respectively). Low phosphorus significantly affected plant growth and yield and reduced fructose content (73% of the control). Plants were not sensitive to low nitrogen and high salinity, possibly as a result of the use of nitrate-based fertilizers and the addition of calcium, respectively. These results provide guidelines for habanero pepper production under suboptimal edaphic conditions.
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Narueworanon, Patthranit, Lakkana Laopaiboon, Niphaphat Phukoetphim e Pattana Laopaiboon. "Impacts of Initial Sugar, Nitrogen and Calcium Carbonate on Butanol Fermentation from Sugarcane Molasses by Clostridium beijerinckii". Energies 13, n. 3 (5 febbraio 2020): 694. http://dx.doi.org/10.3390/en13030694.
Testo completoAbstract (sommario):
Low-cost nitrogen sources, i.e., dried spent yeast (DSY), rice bran (RB), soybean meal (SM), urea and ammonium sulfate were used for batch butanol fermentation from sugarcane molasses by Clostridium beijerinckii TISTR 1461 under anaerobic conditions. Among these five low-cost nitrogen sources, DSY at 1.53 g/L (nitrogen content equal to that of 1 g/L of yeast extract) was found to be the most suitable. At an initial sugar level of 60 g/L, the maximum butanol concentration (PB), productivity (QB) and yield (YB/S) were 11.19 g/L, 0.23 g/L·h and 0.31 g/g, respectively. To improve the butanol production, the concentrations of initial sugar, DSY and calcium carbonate were varied using response surface methodology (RSM) based on Box–Behnken design. It was found that the optimal conditions for high butanol production were initial sugar, 50 g/L; DSY, 6 g/L and calcium carbonate, 6.6 g/L. Under these conditions, the highest experimental PB, QB and YB/S values were 11.38 g/L, 0.32 g/L·h and 0.40 g/g, respectively with 50% sugar consumption (SC). The PB with neither DSY nor CaCO3 was only 8.53 g/L. When an in situ gas stripping system was connected to the fermenter to remove butanol produced during the fermentation, the PB was increased to 15.33 g/L, whereas the YB/S (0.39 g/g) was not changed. However, the QB was decreased to 0.21 g/L·h with 75% SC.
31
Cao, Hui, Jianjun Chen e Dennis B. McConnell. "(130) Dieffenbachia Calcium Oxalate Crystal Formation Affected by Cultivars, Nitrogen Rates, and Light Intensity". HortScience 40, n. 4 (luglio 2005): 1086C—1086. http://dx.doi.org/10.21273/hortsci.40.4.1086c.
Testo completoAbstract (sommario):
Tissue-culturedexplantsofDieffenbachiamaculate`Exotic Perfection', D.`Snow Flake', and D. × `Tropic Breeze' were grown on ebb-and-flow trays subirrigated with nitrogen (N) at 50, 200, or 800 mg·L-1 using a water-soluble fertilizer 17N–2.1P–15.7K for 10 weeks in a shaded greenhouse under a maximum photosynthetic photon flux density of 285 μmol·m-2·s-1. Plants were then transferred to interior rooms under a light level of 8 μmol·m-2·s-1. Samples of the midrib were taken from the first mature leaf of plants before being placed indoors and also from the first mature leaf of plants 8 months after growing indoors. Counts of calcium oxalate crystal idioblasts in cross-sections of the basal midrib using polarized light microscopy showed that the number of crystal idioblasts was higher in all three cultivars fertigated with 200 mg·L-1 N than those fertigated with either 50 or 800 mg·L-1 N. The number of crystal idioblasts in each cultivar grown under 8 μmol·m-2·s-1 was about 50% of the number detected when plants were grown under 285 μmol·m-2·s-1. `Snow Flake' had the highest number of crystal idioblasts with counts up to 60 per cross-section, whereas `Exotic Perfection' had the lowest with only 30 per cross-section. This study shows that in addition to cultivar differences, light intensity and N can significantly affect calcium crystal formation, and the highest number of crystal idioblasts occurred when Dieffenbachia cultivars were grown under optimum conditions.
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Grochowska, Jolanta. "Assessment of Water Buffer Capacity of Two Morphometrically Different, Degraded, Urban Lakes". Water 12, n. 5 (25 maggio 2020): 1512. http://dx.doi.org/10.3390/w12051512.
Testo completoAbstract (sommario):
The research was conducted in Karczemne Lake (area, 40.4 ha; maximum (max.) depth, 3.2 m) and Klasztorne Małe Lake (area, 13.7 ha; max. depth, 20.0 m) located in the Kashubian Lake District (Northern Poland). From the beginning of the 1950s, these reservoirs have received municipal and storm wastewater. The long-term process of lake contamination has shaped the specific buffer capacity conditions and influenced the circulation of carbonate and bicarbonate in the water of these ecosystems. Extremely high concentrations of nutrients (Karczemne Lake: max. total phosphorous (TP) level, 7.5 mg P L−1; max. total nitrogen (TN) level, 5.6 mg N L−1; Klasztorne Małe Lake: max. TP level, 20.6 mg P L−1; max. TN level, 43.3 mg N L−1) have caused very intensive primary production processes (Karczemne Lake: max. chlorophyll-a level, 193.40 µg m−3; max. Secchi disc visibility, 0.85 m; Klasztorne Małe Lake: max. chlorophyll-a level, 160.01 µg m−3; max. Secchi disc visibility, 1.15 m). In the polymictic Karczemne Lake, the pH value of all water columns exceeded 10.0 (max. pH, 10.41), and in the meromictic Klasztorne Małe Lake, the pH of the surface water layers oscillated around 9.5. In the polymictic Karczemne Lake, despite intensive photosynthesis, the calcium content and alkalinity were similar throughout the whole water column due to constant circulation. In the meromictic Klasztorne Małe Lake, during the growing season, a decrease in calcium concentration and alkalinity of the surface water layers and an increase in calcium concentration at the bottom were noted.
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Meraj, MMR, MAS Khan, TA Rakhi e NR Sarker. "Effect of different levels of saturated solution of calcium chloride in the preparation of calcium salt of fatty acid and its effect on rumen protozoa, pH and ammonia nitrogen". Bangladesh Journal of Animal Science 42, n. 2 (31 dicembre 2013): 109–13. http://dx.doi.org/10.3329/bjas.v42i2.18489.
Testo completoAbstract (sommario):
Calcium salt of fatty acid was prepared by adding 3 different levels of saturated solution of calcium chloride (CaCl2) to soybean oil. It was found that fat content was not significantly affected by calcium chloride. However, calcium chloride had significant effect on other parameters like dry matter, fat, ash and sodium. The highest calcium and fat was obtained when 3.5 parts CaCl2 were added (p<0.01). It was also observed that sun drying and drying at room temperature had no significant effect on any parameter except dry matter content. Calcium salt of fatty acid had significant anti-protozoal effect (p<0.01) in sheep. Treated group showed reduced protozoal number without affecting the rumen pH and rumen ammonia nitrogen. It was also found that the number of rumen protozoa in rumen liquor was less at 12:00 p.m. than that at 3:30 p.m. when sheep were fed 3% calcium salt. DOI: http://dx.doi.org/10.3329/bjas.v42i2.18489Bang. J. Anim. Sci. 2013. 42 (2): 109-113
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Spiers, James M., e John H. Braswell. "793 PB 039 CALCIUM, MAGNESIUM, AND NITROGEN FERTILIZTION AFFECTS LEAF NUTRIENT CONTENT AND GROWTH OF `STERLING' MUSCADINE GRAPE". HortScience 29, n. 5 (maggio 1994): 546f—546. http://dx.doi.org/10.21273/hortsci.29.5.546f.
Testo completoAbstract (sommario):
The effects of varying N, Ca, and Mg fertilization levels on plant growth and leaf elemental content of `Sterling' muscadine grapes (Vitis rotundifolia Michaux) were studied in a 2 year sand culture experiment. Increased N levels reduced leaf K, Ca, and Mn and increased leaf N and P concentrations plus plant growth. Calcium fertilization increased leaf Ca, decreased leaf Mg, but did not affect plant growth. Mg fertilization reduced leaf K and Ca and increased leaf Mg plus plant growth. Visual symptoms, assumed to be Mg deficiencies, were decreased by Mg fertilization and highly correlated to leaf Mg content. Plants which received the highest Ca fertilizer level had fewer deficiency symptoms when treated with the highest rate of N. Calcium fertilization tended to slow both Mg uptake and deficiency symptoms reductions caused by increases in levels of applied Mg. Growth of `Sterling' muscadine plants was positively correlated to leaf N and Mg and negatively related to leaf K, Ca, Mn, Zn, and Cu concentrations.
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Cavali, Jucilene, Odilon Gomes Pereira, Sebastião de Campos Valadares Filho, Edson Mauro Santos, Gleidson Giordano Pinto de Carvalho, Márcia Vitória Santos, Marlos Oliveira Porto e Juliana Ferraz Huback Rodrigues. "Bromatological and microbiological characteristics of sugarcane silages treated with calcium oxide". Revista Brasileira de Zootecnia 39, n. 7 (luglio 2010): 1398–408. http://dx.doi.org/10.1590/s1516-35982010000700002.
Testo completoAbstract (sommario):
It was evaluated the addition of calcium oxide (0; 0.5; 1.0; 1.5; and 2.0% of dry matter) effect on the chemical composition and ruminal degradability of the dry matter and neutral detergent fiber, on the losses of dry matter, and on the microbial population in sugar cane silages. A design with five levels of calcium oxide and three replications was used. All the variables were influenced by the addition of calcium oxide in the silages, except the composition in acid detergent insoluble protein, water soluble carbohydrates and lignin. The dry matter content and pH linearly increased while the contents of organic matter, hemicellulose and crude protein linearly decreased with the levels of calcium oxide. Neutral detergent fiber corrected for ashes and protein and acid detergent fiber were adjusted for the quadratic models with calculated minimal values of 33.3 and 22.5% for the levels 1.73 and 1.49% of calcium oxide, respectively. The in vitro digestibility of the dry matter and the content of amoniacal nitrogen adjusted to quadratic models with maximal levels of 80.1% and 9.1% for the levels of 1.8 and 0.7% of calcium oxide, respectively. The minimal production of gas (3.18%) was observed at the level of 1.39% of calcium oxide. Production of effluent and recovery of dry matter of the ensiled mass showed a reduction and a linear increase, respectively, with addition of calcium oxide. The highest lactic acid bacterial population was observed in the silage treated with 1.5% of calcium oxide. The addition of calcium oxide increased degradability of the soluble fraction of the dry matter, which was higher than 50% and reduced the non- degradable fraction of the neutral detergent fiber. Addition of calcium oxide level higher than 1.0% in the sugar cane during ensilage improves in vitro dry matter digestibility and the recovery of dry matter, increases populations of lactic acid bacteria and reduces production of yeasts.
36
Ahmed, A. K., e K. A. Johnson. "The effect of the ammonium: nitrate nitrogen ratio, total nitrogen, salinity (NaCl) and calcium on the oxalate levels ofTetragonia tetragonioidesPallas. Kunz." Journal of Horticultural Science and Biotechnology 75, n. 5 (gennaio 2000): 533–38. http://dx.doi.org/10.1080/14620316.2000.11511280.
Testo completo
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Larsen, Torben, e Hanne Damgaard Poulsen. "The relationship between mineral and nitrogen balances in growing pigs fed diets supplemented with zinc oxide". Canadian Journal of Animal Science 76, n. 3 (1 settembre 1996): 409–15. http://dx.doi.org/10.4141/cjas96-059.
Testo completoAbstract (sommario):
The present study was conducted to determine if there were effects of increasing levels of dietary zinc supplementation on the turnover of zinc and other minerals and trace elements in growing pigs. Thirty crossbred female pigs, with an initial body weight of approximately 25 kg, were randomly assigned to five diets with increasing levels of supplemented zinc (as zinc oxide); i.e. from the intrinsic level of 42 mg kg−1 diet to 72, 105, 170, and 255 mg kg−1, respectively. The animals were subjected to two 7-d balances in metabolic cages, separated by 15 d in pens. Balances consisted of controlled feed intake, i.e. approximately 10% below the expected ad libitum intake, and quantitative collection of feces and urine. Zinc supplementation did not affect nitrogen absorption, excretion, or retention (P > 0.05). The inclusion of zinc oxide did not affect (P > 0.05) weight gain of the animals throughout the 34 d experiment. Neither mineral nor trace element balances, except for zinc, were affected (P > 0.05) by zinc supplementation. Urinary excretion of zinc was not affected (P > 0.05), but zinc absorption and retention calculated in absolute amounts or in proportion to nitrogen retention (i.e. lean body accretion) increased several-fold when diets were supplemented with zinc oxide. Mineral and trace element absorption in proportion to nitrogen retention appeared remarkably constant throughout the experimental period, although feed intake and body size increased with time. Only calcium absorption and retention, determined in proportion to nitrogen retention and as fractions of ingested calcium increased (P < 0.001), 14 and 9%, respectively, with time. In general, mineral and trace element absorption and retention, expressed in proportion to nitrogen retention, appear to be a useful expression for comparisons between observations across time intervals. Key words: Zinc, absorption, retention, interaction, minerals, trace elements
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Wilman, D., e Nthoana Mzamane. "The effect of field drying on the concentrations of some major elements in herbage". Journal of Agricultural Science 107, n. 1 (agosto 1986): 9–13. http://dx.doi.org/10.1017/s0021859600066739.
Testo completoAbstract (sommario):
SUMMARYHerbage from a grass-white clover sward was dried in the field to the hay stage (≤ 0·33 g moisture/g dry matter) at three times of year in 2 years comparing, in each case, all combinations of two stages of maturity, two levels of applied nitrogen and two thicknesses of swath. Samples taken at intervals during drying were analysed for nitrogen, phosphorus, potassium, calcium, magnesium and sodium.When there was little or no rain during drying, there was no change in the concentration of any of the six elements in the herbage dry matter between cutting and the hay stage, whatever the stage of maturity, level of N applied or swath thickness.The concentrations of potassium and sodium in the crop were greatly reduced by rain in the later stages of drying, but were less affected by rain in the early and middle stages; the concentrations of calcium and magnesium appeared to be reduced by rain as readily in the middle as in the later stages; the concentrations of nitrogen and phosphorus were relatively little affected by rain, but seemed likely to be more at risk in the later stages. The extent of the reductions in the concentration of elements was not markedly affected by the stage of maturity or level of N applied. There were reductions in the thin but not in the thick swaths when rain fell during the early and middle stages of drying, probably partly or wholly because the herbage in the thin swaths was drier, with a higher proportion of dead cells, at that time than the herbage in the thick swaths. At least 70 kg K/ha was leached out of the crop in the thick swaths by rain in the late stages of drying.
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Bavec, F., B. Čeh Brežnik e M. Brežnik. "Hop yield evaluation depending on experimental plot area under different nitrogen management". Plant, Soil and Environment 49, No. 4 (10 dicembre 2011): 163–67. http://dx.doi.org/10.17221/4108-pse.
Testo completoAbstract (sommario):
Numerous agricultural and associated ecological effects such as mineral nitrogen fertilising influence the yield of hop (Humulus lupulus L.) cones and its quality. Using a wide spacing of plants (in our case 2.6 × 0.8 m) we want to answer a hypothetical question about an appropriate number of test plants per plot vs. experimental plot area. The aim of this study was to compare the effect of different rates of mineral nitrogen, fertiliser combinations and their nitrogen split application on hop yield evaluated from different plot areas (micro trial: 30 plants per plot; macro trial: 320 plants per plot). Hop yield varied significantly between treatments, plot areas, years and interactions (year × treatment, plot area × treatment) (all at P £ 0.01). Cone yield in a micro trial was higher in all treatments in comparison with yield in a macro trial. In spite of common intensive fertilisation the appropriate fertilising combination and mineral N rate can influence the yield. Target nitrogen rate of160 kg mineral N/ha (at the level from 40.0 to62.5 kg nitrate N/ha in soil depth to0.3 m) and cheaper combination of calcium-ammonium nitrate (50 kg N/ha) at the beginning of vegetation plus urea (110 kg N/ha) for top dressing can be recommended. On plot areas of each size and each year all treatments showed similar trends of fertilising effect on yield. In spite of higher yield in the micro trial and lower coefficient of variation in comparison with the macro trial, the results proved that a risk of incorrect yield analysing in macro trials is very low for field experiments.
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Hatamian, Mansoure, e Mohammad Kazem Souri. "Postharvest Quality of Roses under Different Levels of Nitrogenous Compounds in Holding Solution". Open Agriculture 4, n. 1 (8 marzo 2019): 79–85. http://dx.doi.org/10.1515/opag-2019-0007.
Testo completoAbstract (sommario):
Abstract Nitrogen (N) forms and N levels can have a great impact on growth and quality of agricultural crops. Postharvest N treatments may also affect the quality of products. This study was conducted under laboratory conditions to evaluate the changes in postharvest quality characteristics of cut roses (Rosa hybrid cv ‘Utopia’) under different nitrogen concentrations of holding solution. Three nitrogen sources including ammonium sulfate, calcium nitrate and potassium nitrate at five concentrations (0, 5, 10, 15 and 20 mgL-1 N) were applied into vases with holding solution. The results showed that low ammonium (5 mg L-1) and high nitrate (20 mgL-1) resulted in the highest leaf SPAD values, whereas the lowest values were recorded for those stems treated with the two highest ammonium concentrations (15 and 20 mg L-1). Leaf and petal relative water contents (RWC) were significantly reduced by higher ammonium concentrations, while they were increased by increasing calcium nitrate and potassium nitrate concentrations in the vase holding solution. Leaf catalase activity was increased by the two lowest (5 and 10 mg L-1) and decreased by the two highest ammonium levels (15 and 20 mg L-1), and it was not affected by the two other nitrogen salts. Higher ammonium levels resulted in a significant increase in leaf proline concentrations and petal ion leakage, whereas nitrate concentrations reduced these two traits. A low concentration of ammonium (5 mg L- 1) increased flower vase life while higher ammonium concentrations reduced the trait. There was also an increasing trend in flower vase life with higher concentrations of both nitrate salts. Therefore, low ammonium or high nitrate levels in vase holding solution can improve vase life quality of cut roses.
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Salles, Márcia Saladini Vieira, Marcus Antonio Zanetti, Fernando André Salles, Evaldo Antonio Lencioni Titto e Renata Maria Consentino Conti. "Changes in ruminal fermentation and mineral serum level in animals kept in high temperature environments". Revista Brasileira de Zootecnia 39, n. 4 (aprile 2010): 883–90. http://dx.doi.org/10.1590/s1516-35982010000400025.
Testo completoAbstract (sommario):
In order to evaluate the effect of environmental temperature on ruminal fermentation and on mineral levels of growing ruminants, it was used 12 male calves (initial average weight 82.9 ± 7.7 kg, 100 days of age), were employed in a randomized block design (by weight) experiment, with repeated weight measurement and two environmental temperatures: thermoneutral (24ºC) and heat-stressed (33ºC), during 38 days. The animals exposed to 33ºC presented lower dry matter ingestion, lower T3 (triiodothyronine) serum level, higher ammoniacal nitrogen (NH3-N) level in the rumen liquid, and higher rectal and body temperatures during all the experimental period when compared to the animals kept in thermoneutral environment (24ºC). The animals kept under heat stress environment (33ºC) presented higher calcium serum level, which was the highest on 31st day and the lowest on the 38th day of the experiment; phosphorus level was the lowest during all the experimental period; sodium level was lower on the 17th, 31st and 38th experimental days. Potassium and zinc levels were lower after 24 days; copper level was lower until the 24th day; magnesium level was higher until the 17th day, if compared to the ones from the animals kept in thermoneutral environment (24ºC). The heat-stressed animals presented higher levels of ammoniacal nitrogen in the ruminal liquid and a decrease in the phosphorus, sodium, potassium and zinc serum levels. These results show the necessity of changes on feed management to ruminants in temperatures over the thermal comfort limits so that performance loss is decreased.
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Muscher, Alexandra, e Korinna Huber. "Effects of a reduced nitrogen diet on calcitriol levels and calcium metabolism in growing goats". Journal of Steroid Biochemistry and Molecular Biology 121, n. 1-2 (luglio 2010): 304–7. http://dx.doi.org/10.1016/j.jsbmb.2010.03.084.
Testo completo
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Ndidi, Uche Samuel, Charity Unekwuojo Ndidi, Abbas Olagunju, Aliyu Muhammad, Francis Graham Billy e Oche Okpe. "Proximate, Antinutrients and Mineral Composition of Raw and Processed (Boiled and Roasted) Sphenostylis stenocarpa Seeds from Southern Kaduna, Northwest Nigeria". ISRN Nutrition 2014 (16 marzo 2014): 1–9. http://dx.doi.org/10.1155/2014/280837.
Testo completoAbstract (sommario):
This research was aimed at evaluating the proximate composition, level of anti-nutrients, and the mineral composition of raw and processed Sphenostylis stenocarpa seeds and at examining the effect of processing on the parameters. From the proximate composition analysis, the ash content showed no significant difference (P>0.05) between the processed and unprocessed (raw) samples. However, there was significant difference (P<0.05) in the levels of moisture, crude lipid, nitrogen-free extract, gross energy, true protein, and crude fiber between the processed and unprocessed S. stenocarpa. Analyses of the antinutrient composition show that the processed S. stenocarpa registered significant reduction in levels of hydrogen cyanide, trypsin inhibitor, phytate, oxalate, and tannins compared to the unprocessed. Evaluation of the mineral composition showed that the level of sodium, calcium, and potassium was high in both the processed and unprocessed sample (150–400 mg/100 g). However, the level of iron, copper, zinc, and magnesium was low in both processed and unprocessed samples (2–45 mg/100 g). The correlation analysis showed that tannins and oxalate affected the levels of ash and nitrogen-free extract of processed and unprocessed seeds. These results suggest that the consumption of S. stenocarpa will go a long way in reducing the level of malnutrition in northern Nigeria.
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Tawfik, Ahmed A., e Jiwan P. Palta. "MITIGATION OF HEAT STRESS EFFECTS ON POTATO GROWTH BY CALCIUM AND NITROGEN APPLICATION DURING STRESS". HortScience 27, n. 6 (giugno 1992): 596f—596. http://dx.doi.org/10.21273/hortsci.27.6.596f.
Testo completoAbstract (sommario):
The optimum temperature regime for Solanum tuberosum cv. Russet Burbank is usually 20/15°C day/night. We studied the impact of heat stress (30/25°C, day/night) on the growth of this heat sensitive cultivar under controlled conditions (UW-Biotron). Plants were grown in sandy-loam soil which tested at 1500 Kg/ha Ca. Plants were at the maximum temperature for 6h during the middle of the day with a photoperiod of 14 hrs. All pots received identical amounts of total N (rate: 225 Kg N ha1.). The treatments were: (1) NSN: non-split N (N application 1/2 emergence, 1/2 two wks later): (2) SPN: split-N (1/2 emergence 1/6 at 2, 5 and 8 wks later); (3) SPN+Ca: Split-N+Ca (Ca at 2, 5 and 8 wks after emergence, total Ca from CaNO3 was 113 Kg ha1). Total leaf FWT and DWT was significantly reduced in NS treatment by heat stress at 13 wks as compared to optimum conditions. However, this was not reduced in SPN and SPN+Ca. Under heat stress: (a) SPN + Ca gave the highest leaf FWT and DWT, stomatal conductance, transpiration rate, and leaflet tissue Ca content; (b) Young expanding leaflets gave higher growth rate with SPN and SPN + Ca than NSN; (c) Ca content of mature leaflet decreased progressively in both NSN and SPN but not in SPN + Ca. Our results show that application of Ca and N during heat stress can mitigate stress effects and that maintenance of a certain level of calcium in leaf tissue is important under heat stress.
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Hedman, Craig Wallace, e Dan Binkley. "Canopy profiles of some Piedmont hardwood forests". Canadian Journal of Forest Research 18, n. 8 (1 agosto 1988): 1090–93. http://dx.doi.org/10.1139/x88-166.
Testo completoAbstract (sommario):
Relationships between canopy profiles and site quality were examined in 11 old, uneven-aged (>180 years) hardwood forests in the Piedmont of eastern North Carolina. Site fertility was indexed by extractable soil calcium and phosphorus, by the content of calcium, phosphorus and nitrogen in litter fall, and by the aboveground net primary productivity of each stand. Canopy profiles were indexed by the leaf area index for each 3.3-m height interval. Total leaf area index correlated highly with most measures of site fertility, but we found no clear patterns between canopy profiles and any measure of site fertility. We conclude that site fertility is reflected in broad ecosystem-level variables such as total leaf area index and stand productivity, but that detailed patterns such as canopy profiles relate strongly to specific stand composition, age structure, and history.
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Marler, Thomas E., e Murukesan V. Krishnapillai. "Incident Light and Leaf Age Influence Leaflet Element Concentrations of Cycas micronesica Trees". Horticulturae 5, n. 3 (7 agosto 2019): 58. http://dx.doi.org/10.3390/horticulturae5030058.
Testo completoAbstract (sommario):
The need for improved knowledge on conservation and management of cycad species has generated recent interest in compiling a database on leaf nutrient concentrations. However, the sampling protocols have not been consistent among reports and the influences of some plant and habitat traits on the plasticity of cycad leaf nutrient concentrations has not been adequately determined. We used Cycas micronesica K.D. Hill trees to determine the role of incident light level and leaf age on leaflet content of 11 essential elements. Shade leaves exhibited increased mass-based concentration for nitrogen, phosphorus, and potassium above that of sun leaves. Shade leaves exhibited decreased area-based concentration for all of the macro- and micronutrients below that of sun leaves. Mass-based concentration of nitrogen, phosphorus, and potassium decreased with leaf age, and that of calcium, magnesium, iron, manganese, and zinc increased with leaf age. These findings indicate the relative leaf age and the amount of shade or incident light at the leaf level must be recorded and reported for leaf tissue studies in cycads in order to reduce ambiguity and ensure repeatability.
47
Brown, C. J., e P. J. Scott. "Environmental parameters influencing the distribution of Platanthera blephariglottis and Platanthera clavellata (Orchidaceae) in peatlands on the Avalon Peninsula, Newfoundland". Canadian Journal of Botany 75, n. 6 (1 giugno 1997): 974–80. http://dx.doi.org/10.1139/b97-108.
Testo completoAbstract (sommario):
Populations of two terrestrial species of orchids, Platanthera blephariglottis (Willd.) Lindl. and Platanthera clavellata (Michx.) Luer, were investigated for two field seasons (1991-1992) to determine what environmental factors (substrate constituents, water pH, water level) may influence their distributions within a peatland. Peat constituent values (magnesium, phosphorus, nitrogen, potassium, iron, calcium, pH, moisture, organic matter, ash) associated with individual species were, for the most part, not significantly different among sites or between species, although the values associated with P. clavellata tended to be higher and to have a greater range than those associated with P. blephariglottis. Water level values associated with species were significantly different between species, suggesting mat it is on this basis that these species partition their habitat. Key words: water level, environmental parameters, distribution, peatland, Platanthera blephariglottis, Platanthera clavellata.
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Węgiel, Andrzej, Ernest Bielinis e Krzysztof Polowy. "Macronutrient Stocks in Scots Pine Stands of Different Densities". Forests 9, n. 10 (22 settembre 2018): 593. http://dx.doi.org/10.3390/f9100593.
Testo completoAbstract (sommario):
A positive nutrient balance is crucial to sustaining forest productivity. Differences in stand densities usually mean different aboveground biomass stocks and different proportions of tree compartments. These differences can be reflected in the different macronutrient stocks between stands of different densities, because various tree compartments have different element concentrations. In this study, 82-year-old stands of Scots pine were compared, and specifically, the concentrations of the elements in tree compartments and the amounts of macronutrients in aboveground biomass were compared. The nutrients considered in this study were nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. A positive correlation between stand density and the level of stored macronutrients was found for nitrogen, phosphorus, and potassium. This result means that forest managers can influence nutrient balances by regulating stand densities or by harvesting methods (SOH: stem-only harvesting or WTH: whole-tree harvesting).
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Mahalinganathan, K., e M. Thamban. "Potential genesis and implications of calcium nitrate in Antarctic snow". Cryosphere Discussions 9, n. 6 (6 novembre 2015): 6125–51. http://dx.doi.org/10.5194/tcd-9-6125-2015.
Testo completoAbstract (sommario):
Abstract. Among the large variety of particulates in the atmosphere, calcic mineral dust particles have highly reactive surfaces that undergo heterogeneous reactions with nitrogen oxides contiguously. The association between Ca2+, an important proxy indicator of mineral dust and NO3–, a dominant anion in the Antarctic snow pack was analysed. A total of 41 snow cores (~ 1 m each) that represent snow deposited during 2008–2009 were studied along coastal–inland transects from two different regions – the Princess Elizabeth Land (PEL) and central Dronning Maud Land (cDML) in East Antarctica. Correlation statistics showed a strong association (at 99 % significance level) between NO3– and Ca2+ at the near-coastal sections of both PEL (r = 0.72) and cDML (r = 0.76) transects. Similarly, a strong association between these ions was also observed in snow deposits at the inland sections of PEL (r = 0.8) and cDML (r = 0.85). Such systematic associations between Ca2+ and NO3– is attributed to the interaction between calcic mineral dust and nitrogen oxides in the atmosphere, leading to the possible formation of calcium nitrate (Ca(NO3)2). Forward and back trajectory analyses using HYSPLIT model v. 4 revealed that Southern South America (SSA) was an important dust emitting source to the study region, aided by the westerlies. Particle size distribution showed that over 90 % of the dust was in the range < 4 μm, indicating that these dust particles reached the Antarctic region via long range transport from the SSA region. We propose that the association between Ca2+ and NO3– occurs during the long range transport due to the formation of Ca(NO3)2. The Ca(NO3)2 thus formed in the atmosphere undergo deposition over Antarctica under the influence of anticyclonic polar easterlies. However, influence of local dust sources from the nunataks in cDML evidently mask such association in the mountainous region. The study indicates that the input of dust-bound NO3– may contribute a significant fraction of the total NO3– deposited in Antarctic snow.
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Campos, Ricardo, e David Wm Reed. "Influence of Irrigation Water Salinity on Optimal Nitrogen, Phosphorus, and Potassium Liquid Fertilizer Rates for Spathiphyllum ‘Petite’". Journal of Environmental Horticulture 12, n. 2 (1 giugno 1994): 104–7. http://dx.doi.org/10.24266/0738-2898-12.2.104.
Testo completoAbstract (sommario):
Abstract The experiment was a 5 × 5 factorial composed of 5 fertilizer levels and 5 salinity levels applied to Spathiphyllum ‘Petite’. Fertilizer levels were 0, 125, 250, 375 and 500 mg/l (ppm) N from a 24N-3.4P-13.3K (24-8-16) soluble fertilizer. Salinity levels were 0, 500, 1000, 1500 and 2000 mg/l (ppm) from NaCl:CaCl2 in a 1:1 equivalent ratio. Maximum growth was observed at 250 mg/l N and no salts. At the highest salinity level tested (2000 mg/l), maximum growth was observed at 125 mg/l N. Generally, as salinity level increased the measured growth parameters decreased. Leaf calcium, sodium, and chloride increased with increasing levels of salinity in the irrigation water. Leaf nitrogen, phosphorus, and potassium generally increased with increasing levels of fertilizer, but were not affected by salinity levels. It is possible that high sodium and chloride concentration in leaves produced an ion toxicity.