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1
KUMAR, YOGENDRA. "Nanofertilizers for enhancing nutrient use efficiency, crop productivity and economic returns in winter season crops of Rajasthan". Annals of Plant and Soil Research 22, n. 4 (4 novembre 2020): 324–35. http://dx.doi.org/10.47815/apsr.2020.10001.
Testo completoAbstract (sommario):
The results of 600 on-farm trials with 8 crops conducted during winter season in different districts of Rajasthan have proved that the quantity of urea being applied by the farmers to supply nitrogen to the crops can be successfully reduced to half. The yields obtained with 50% less nitrogen plus 2 sprays of nano-nitrogen in standing crops gave yields higher than that applied in most of the 8 crops tested in these trials. Apart from this, effect of the Nano-Zn and Nano-Cu was also evaluated. As the deficiencies of these micronutrients were not universal like nitrogen, the significant responses to these nanofertilizers depended on the magnitude of deficiency of specific micronutrients and the nature of the crops.These results clearly establish that with application of nanofertilizers, the nutrient use efficiency can be significantly enhanced as revealed by 50 per cent saving of urea through 2 sprays of Nano N.Nanofertilizers are considered as a novel approach towards saving of nutrients, in particular nitrogen, and protecting the environment.This paper describes the results of 600 on-farm trials conducted on 8 crops grown during winter season of 2019-20.
2
Kubát, J., J. Klír e D. Pova. "The dry nitrogen yields nitrogen uptake, and the efficacy on nitrogen fertilisation in long-term experiment in Prague". Plant, Soil and Environment 49, No. 8 (10 dicembre 2011): 337–45. http://dx.doi.org/10.17221/4134-pse.
Testo completoAbstract (sommario):
Long-term field experiments conducted under different soil and climate conditions and their databases provide invaluable information and are indispensable means in the study of the productivity and sustainability of the soil management systems. We evaluated the results of the dry matter yields of the main products obtained with four variants of organic and mineral fertilisation in three long-term field experiments established in 1955. The experiments differed in the cultivated crops. The period of evaluation was 12 and 16 years (1985–2000), respectively. The productivity of nine-year crop rotation was lower with the fertilised variants than that with the alternative growing of spring wheat and sugar beets. The dry matter yields on the Nil variants, however, were higher in the crop rotation than in the alternate sugar beet and spring wheat growing, apparently due to the symbiotic nitrogen fixation. The dry matter yields of sugar beet and mainly of spring wheat declined in almost all variants of fertilisation in the alternate sugar beet and spring wheat growing, over the evaluated time period. In spite of the relatively high dry matter production, the declining yields indicated a lower sustainability of the alternate cropping system. Both organic and mineral fertilisation increased the production of the cultivated crops. The differences in the average dry matter yields were statistically significant. Both organic and mineral fertilisation enhanced significantly the N-uptake by the cultivated crops. The effectivity of nitrogen input was the highest with the alternate cropping of sugar beet and spring wheat indicating that it was more demanding for the external N-input and thus less sustainable than nine-year crop rotation.
3
Yamagata, Makoto, e Noriharu Ae. "Nitrogen uptake response of crops to organic nitrogen". Soil Science and Plant Nutrition 42, n. 2 (1 giugno 1996): 389–94. http://dx.doi.org/10.1080/00380768.1996.10415110.
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Tei, Francesco, Stefaan De Neve, Janjo de Haan e Hanne Lakkenborg Kristensen. "Nitrogen management of vegetable crops". Agricultural Water Management 240 (ottobre 2020): 106316. http://dx.doi.org/10.1016/j.agwat.2020.106316.
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Jensen, Erik Steen. "Nitrogen Accumulation and Residual Effects of Nitrogen Catch Crops". Acta Agriculturae Scandinavica 41, n. 4 (gennaio 1991): 333–44. http://dx.doi.org/10.1080/00015129109439917.
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Gaskell, Mark, e Richard Smith. "Nitrogen Sources for Organic Vegetable Crops". HortTechnology 17, n. 4 (gennaio 2007): 431–41. http://dx.doi.org/10.21273/horttech.17.4.431.
Testo completoAbstract (sommario):
Fertilization is the most expensive cultural practice for the increasing numbers of organic vegetable growers in the United States. Nitrogen (N) is the most important and costly nutrient to manage, and cost-effective N management practices are needed for efficient organic vegetable production. There is a wide array of organic N sources available, but they vary in cost, N content, and N availability. Compost and cover crops are commonly used sources of N for vegetables because they are relatively inexpensive and offer additional nutrients or soil improvement qualities in addition to N. Studies have shown that compost quality factors that affect N mineralization vary by source and among different batches from the same source. Compost carbon to N ratio should be equal to or less than 20:1 to assure net short-term mineralization. Cover crops also vary in N content and mineralization rate after incorporation. Leguminous cover crops decompose and release N more rapidly than grass or cereal cover crops at the preheading stage typically incorporated. Even the most efficient N-supplying composts, cover crops, or other organic N sources do not release appreciable N to a subsequent crop beyond 6 to 8 weeks from incorporation, and this burst of early N may not synchronize with N requirements for many vegetable crops. Other potential organic fertilizer N sources have been evaluated for vegetables, and they vary in N cost and N mineralization rate. Materials evaluated include seabird guano, liquid fish, feather meal, corn meal (Zea mays), blood meal, and liquid soybean meal (Glycine max) among others. Of those evaluated, feather meal, seabird guano, and liquid fish stand out as more economical organic sources of available N. Organic sources generally lack uniformity and are bulky, unstable, and inconsistent as a group, and this contributes to additional hidden management costs for organic growers. Liquid organic N sources for use in microirrigation systems may have additional disadvantages caused by loss of valuable nutrient N that is removed by filters.
7
Barnett, Bobby D. "Nitrogen-Fixing Trees Benefit Rotation Crops". Journal of Forestry 84, n. 11 (1 novembre 1986): 48–49. http://dx.doi.org/10.1093/jof/84.11.48.
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Balbinot Junior, Alvadi Antonio, Milton da Veiga, Anibal de Moraes, Adelino Pelissari, Álvaro Luiz Mafra e Cristiano Dela Piccolla. "Winter pasture and cover crops and their effects on soil and summer grain crops". Pesquisa Agropecuária Brasileira 46, n. 10 (ottobre 2011): 1357–63. http://dx.doi.org/10.1590/s0100-204x2011001000032.
Testo completoAbstract (sommario):
The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N) fertilization (intercropping cover); the same intercropping, with grazing and 100 kg ha-1 of N per year topdressing (pasture with N); the same intercropping, with grazing and without nitrogen fertilization (pasture without N); oilseed radish, without grazing and nitrogen fertilization (oilseed radish); and natural vegetation, without grazing and nitrogen fertilization (fallow). Intercropping cover produces a greater amount of biomass in the system and, consequently, a greater accumulation of total and particulate organic carbon on the surface soil layer. However, land use in winter does not significantly affect soil physical properties related to soil compaction, nor the grain yield of maize, soybean and common bean cultivated in succession.
9
Ahmadi, Ahmad Yar. "Relations of Legumes with Soil Health and Succeeding Crops". Open Access Journal of Agricultural Research 8, n. 4 (2023): 1–9. http://dx.doi.org/10.23880/oajar-16000333.
Testo completoAbstract (sommario):
In recent decades, soil degradation has increased dramatically on a global scale. It is urgently necessary to promote food security and lessen the effects of climate change by restoring and maintaining the health of our soils. Improvements in soil structure have been demonstrated to help mitigate the effects of soil degradation, which is a crucial feature that influences soil health that is becoming more widely acknowledged. So the use of technologies and methods are important in this context. Growing of legume crops in cropping system is an option. Legumes possess a unique attribute known as nitrogen fixation, which enables them to form symbiotic associations with nitrogen-fixing bacteria residing within specialized root structures called nodules. Through this remarkable process, atmospheric nitrogen is converted into a biologically available form, enriching the soil with this essential nutrient and reducing the dependence on synthetic nitrogen inputs and minimizing environmental degradation caused by excessive fertilizer usage. Furthermore, legumes actively participate in nutrient recycling, releasing essential elements within the soil. By absorbing nutrients from deep in the soil profile, legumes prevent leaching and subsequent loss of these valuable resources. In addition to their nutrient recycling power, legumes also play an important role in improving soil structure. Their extensive root systems penetrate deep into the soil, effectively breaking up compacted layers and enhancing water infiltration. In conclusion, recognizing and harnessing the potential of legumes can revolutionize farming practices, ensuring long-term soil fertility and productivity, environmental sustainability, and food security for generations to come.
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ȘIMON, Alina, Adrian CECLAN, Florin RUSSU, Marius BĂRDAȘ, Felicia CHEȚAN e Alin POPA. "INFLUENCE OF NP MINERAL FERTILIZATION ON SOYBEAN CROPS". LIFE SCIENCE AND SUSTAINABLE DEVELOPMENT 3, n. 1 (29 luglio 2022): 84–90. http://dx.doi.org/10.58509/lssd.v3i1.171.
Testo completoAbstract (sommario):
Soybean is one of the most important sources of vegetable protein, having a great agronomic importance by fixing atmospheric nitrogen following symbiosis with bacteria of the genus Rhizobium. Bifactorial experience, of the AxB model A - phosphorus doses: P0; P40; P80; P120; P16 and B - nitrogen doses:N0; N25; N50; N75; N100, aims to identify the influence of these doses on the development of soybean cultivation. Although soybeans are a heavy consumer of nitrogen and phosphorus in the early stages of development, however, they do not react well to large amounts of nitrogen as they prevent the development of the number of nodules on soybean roots and inhibits the growth of bacteria, and the increases obtained production do not justify the higher amount of nitrogen applied to soybeans. The number of pods and the mass of 1000 grains are also influenced more by the application of phosphorus doses than nitrogen. Phosphorus applied in higher amounts leads to an increase of over 60% of the number of nodules but also at significant production increases of 5-7%, compared to the non-fertilized variant. On nutrient-rich soils, soybeans do not require fertilization with large amounts of nitrogen, but they react very well to the application of phosphorus fertilizers.
11
Mangan, Francis X., e Stephen J. Herbert. "WINTER-KILLED LEGUMINOUS COVER CROPS FOR SWEET CORN". HortScience 27, n. 11 (novembre 1992): 1161f—1161. http://dx.doi.org/10.21273/hortsci.27.11.1161f.
Testo completoAbstract (sommario):
Field research was conducted in Deerfield, Mass. to study the effects of leguminous cover crops on sweet corn yield. Oat was planted alone and in combination with four leguminous cover crops August 8, 1990. Cover crop residue was disked once and sweet corn seeded April 23, 1991. Each cover crop combination had three rates of nitrogen added in two applications. Sweet corn seeded into stands of hairy vetch (Vicia villosa) yielded the highest of the cover crop combinations. All leguminous cover crop treatments yielded higher than oat alone or no cover crop when no synthetic nitrogen was added. Cover crop combinations were seeded again in the same field plots August 12, 1991. Oat biomass in November was greater where there had been leguminous cover crops or high rates of synthetic nitrogen. Legume growth was retarded in the plots that had previously received high nitrogen. It is thought that legume growth was reduced in the high nitrogen treatments due to increased oat growth and higher soil nitrogen levels which could inhibit root nodulation.
12
Volynkina, O. V. "Duration of the Aftereffect of Mineral Fertilizers in the Experience of the Kurgan Research Institute". Агрохимия, n. 4 (1 aprile 2023): 44–50. http://dx.doi.org/10.31857/s0002188123040154.
Testo completoAbstract (sommario):
The effect of nitrogen-phosphorus fertilizer for 5 rotations of a 4-field grain crop rotation in the stationary experiment of the Kurgan Research Institute was studied. Different nitrogen distribution between crop rotation crops was tested. When the entire crop rotation dose of nitrogen was applied to the first field, the fertilizer had an aftereffect on the yield of the next 3 crops. Similarly, when dividing the nitrogen dose into the 1st and 3rd fields, an increase in crop yields was noted in the 2nd and 4th crops. The different distribution of nitrogen between crop rotation crops gave similar effects under experimental conditions with the manifestation of the advantage of using nitrogen in crop rotation in a year. For the next 27 years, fertilizers were not applied on these backgrounds and the aftereffect of fertilizer applied in total doses of N1050–1575P840 for 21 years was taken into account in permanent wheat crops. At the 1st dose of nitrogen, the fertilizer had a significant aftereffect for 5 years, at the 2nd – 9, but also later. In years with sufficient moisture, an increase in yield was observed from the aftereffect of nitrogen-phosphorus fertilizer.
13
Thilakarathna, Malinda S., Stephanie Serran, John Lauzon, Ken Janovicek e Bill Deen. "Management of Manure Nitrogen Using Cover Crops". Agronomy Journal 107, n. 4 (luglio 2015): 1595–607. http://dx.doi.org/10.2134/agronj14.0634.
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Paparozzi, Ellen T. "NITROGEN AND SULFUR INTERACTION IN FLORICULTURAL CROPS". Acta Horticulturae, n. 481 (gennaio 1999): 379–84. http://dx.doi.org/10.17660/actahortic.1999.481.44.
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Yan, Ming, Genxing Pan, Jocelyn M. Lavallee e Richard T. Conant. "Rethinking sources of nitrogen to cereal crops". Global Change Biology 26, n. 1 (2 dicembre 2019): 191–99. http://dx.doi.org/10.1111/gcb.14908.
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Bot, Jacques Le, e Stéphane Adamowicz. "Nitrogen Nutrition and Use in Horticultural Crops". Journal of Crop Improvement 15, n. 2 (16 giugno 2006): 323–67. http://dx.doi.org/10.1300/j411v15n02_10.
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Echeverría, H. E., C. A. Navarro e F. H. Andrade. "Nitrogen nutrition of wheat following different crops". Journal of Agricultural Science 118, n. 2 (aprile 1992): 157–63. http://dx.doi.org/10.1017/s0021859600068738.
Testo completoAbstract (sommario):
SUMMARYA trial using a split-plot with blocks design was carried out at the INTA Balcarce Experimental Station, Argentina on a typic argiudol soil to evaluate N nutrition in wheat after different preceding crops and using two rates of N fertilization (0 and 90 kg N/ha).Wheat (Triticum aestivum), soyabean (Glycine max), sunflower (Helianthus annuus) and maize (Zea mays) were grown in different combinations for two successive years (1984/85 and 1985/86).No water stress was detected during either growing season. Nitrogen availability was altered by the previous crops grown, but the effect lasted only for one season. Wheat following maize yielded least with no N and responded most to N fertilization. The highest yields of wheat without N and the lowest response by wheat to N fertilization were found after crops of soyabean and sunflower.Wheat after a fertilized wheat crop did not respond to N fertilization because of a serious attack of take-all (Gaeumannomyces graminis tritici).The nitrate concentration in wheat stem bases was found to be a good estimator of the availability of soil N.
18
Keulen, H., e W. Stol. "Quantitative aspects of nitrogen nutrition in crops". Fertilizer Research 27, n. 2-3 (marzo 1991): 151–60. http://dx.doi.org/10.1007/bf01051123.
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Rahn, C. R. "NITROGEN AND FIELD PRODUCTION OF VEGETABLE CROPS". Acta Horticulturae, n. 533 (giugno 2000): 361–70. http://dx.doi.org/10.17660/actahortic.2000.533.44.
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Sørensen, Jørn Nygaard, e Kristian Thorup-Kristensen. "Nitrogen effects of non-legume catch crops". Zeitschrift für Pflanzenernährung und Bodenkunde 156, n. 1 (1993): 55–59. http://dx.doi.org/10.1002/jpln.19931560109.
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Nakhone, Lenah N., e M. Ali Tabatabai. "Nitrogen mineralization of leguminous crops in soils". Journal of Plant Nutrition and Soil Science 171, n. 2 (aprile 2008): 231–41. http://dx.doi.org/10.1002/jpln.200625162.
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Heege, Hermann J., e Stefan Reusch. "Nitrogen and the Colour of the Crops". German Research 24, n. 2-3 (dicembre 2002): 8–10. http://dx.doi.org/10.1002/germ.200290015.
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Iduna, Arduini, Cardelli Roberto e Pana Silvia. "Biosolids affect the growth, nitrogen accumulation and nitrogen leaching of barley". Plant, Soil and Environment 64, No. 3 (21 marzo 2018): 95–101. http://dx.doi.org/10.17221/745/2017-pse.
Testo completoAbstract (sommario):
Biosolids are organic fertilisers derived from treated and stabilised sewage sludge that increase soil fertility and supply nitrogen to crops over a long period, but can also increase the risk of nitrogen (N) leaching. In this work, spring barley was grown in lysimeters filled with soil amended with biosolids, and with and without mineral N fertilisation. Biomass and the N concentration and content of shoots and roots were determined at flowering and maturity, and the N remobilization was calculated during grain filling. Drainage water was collected and analysed for N leaching. Biosolids increased soil porosity and soil nitrate, and positively affected the growth and N uptake of barley. Compared to mineral fertilisers, biosolids produced 18% higher vegetative biomass and 40% higher grain yield. During grain filling, both N uptake and N remobilization were higher with biosolids, which increased the grain N content by 32%. Nitrogen loss in leachates was 1.2% of plant uptake with mineral fertilisers and 1.7% with biosolids. Thus, soil fertilisation with biosolids greatly benefits spring barley, only slightly increasing N leaching.
24
Haynes, R. J., R. J. Martin e K. M. Goh. "Nitrogen fixation, accumulation of soil nitrogen and nitrogen balance for some field-grown legume crops". Field Crops Research 35, n. 2 (novembre 1993): 85–92. http://dx.doi.org/10.1016/0378-4290(93)90141-9.
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Papendick, Robert I., Lloyd F. Elliott e James F. Power. "Alternative production systems to reduce nitrates in ground water". American Journal of Alternative Agriculture 2, n. 1 (1987): 19–24. http://dx.doi.org/10.1017/s0889189300001442.
Testo completoAbstract (sommario):
AbstractEvidence indicates a strong positive relationship between increases in nitrogen fertilizer use on cropland and nitrate concentrations in shallow ground water. This raises concern about the fate and efficiency of nitrogen fertilizer with current farming practices. Approximately 50 percent of the nitrogen fertilizer applied may be recovered by agronomic crops and 35 percent or less removed in the harvested grain of a crop such as corn. The residual nitrogen is subject to loss by several processes, one being leaching from the crop root zone. Alternative production systems that provide ground water protection must give attention to improved management of nitrogen fertilizer and to practices that minimize the need for nitrogen fertilizer and reduce soil nitrate concentrations. Most important in nitrogen fertilizer management is to more closely match nitrogen availability in the soil with crop needs and to avoid over-fertilization. Nitrogen fertilizer use can be reduced by alternate cropping of low and high nitrogen-demanding crops, use of legumes in the crop rotation to fix nitrogen, and proper use of manures, crop residues, and other organic wastes. Residual nitrates in soil can be reduced by use of cover crops, nitrogen-scavenging crops in the rotation, and alternating shallow and deep-rooted crops. Conservation tillage alone as used with many conventional cropping systems will probably not change the current status of nitrate leaching. Practices used by organic farmers should be carefully studied as possible approaches for ground water protection and adaptation into conservation tillage systems for conserving soil and water resources.
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Volkohon, V. V., S. B. Dimova, K. I. Volkohon, L. M. Tokmakova, M. A. Zhurba, Y. M. Halep, N. P. Shtanko e N. V. Lutsenko. "BIOLOGICAL ASPECTS OF CROPS FERTILIZING SYSTEMS". Agriciltural microbiology 22 (29 dicembre 2015): 13–29. http://dx.doi.org/10.35868/1997-3004.22.13-29.
Testo completoAbstract (sommario):
The process of nitrogen fixation and N2O emission in the system “soil – plant” was studied in the conditions of field stationary experiment on leached black soil when growing crops in short rotation crop succession (potato – barley – peas – winter wheat) in case of different fertilization systems and application of microbial agents. Using directivity indexes of processes of nitrogen biological transformation in agrocoenosis and economic calculations an environmental and economic rationale for fertilization was composed.
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Liu, Xiaoli, Qiuwen Chen e Zhaoxia Zeng. "Study on nitrogen load reduction efficiency of agricultural conservation management in a small agricultural watershed". Water Science and Technology 69, n. 8 (11 febbraio 2014): 1689–96. http://dx.doi.org/10.2166/wst.2014.076.
Testo completoAbstract (sommario):
Different crops can generate different non-point source (NPS) loads because of their spatial topography heterogeneity and variable fertilization application rates. The objective of this study was to assess nitrogen NPS load reduction efficiency by spatially adjusting crop plantings as an agricultural conservation management (ACM) measure in a typical small agricultural watershed in the black soil region in northeast China. The assessment was undertaken using the Soil and Water Assessment Tool (SWAT). Results showed that lowland crops produce higher nitrogen NPS loads than those in highlands. It was also found that corn gave a comparatively larger NPS load than soybeans due to its larger fertilization demand. The ACM assessed was the conversion of lowland corn crops into soybean crops and highland soybean crops into corn crops. The verified SWAT model was used to evaluate the impact of the ACM action on nitrogen loads. The results revealed that the ACM could reduce NO3-N and total nitrogen loads by 9.5 and 10.7%, respectively, without changing the area of crops. Spatially optimized regulation of crop planting according to fertilizer demand and geological landscapes can effectively decrease NPS nitrogen exports from agricultural watersheds.
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Ramazanova, R. Kh, S. I. Tanirbergenov, M. N. Poshanov, A. I. Suleimenova, A. K. Abay e S. N. Duisekov. "Mineral nitrogen content in light serozem soils and the size of nitrogen emission under fertilizer appliciation". Pochvovedenie i agrokhimiya, n. 3 (15 ottobre 2023): 84–98. http://dx.doi.org/10.51886/1999-740x_2023_3_84.
Testo completoAbstract (sommario):
The article presents the results of studies on the impact of bioorganic fertilizers on the cultivation of winter wheat, sugar beet, and soybeans in irrigated light sierozems of southeastern Kazakhstan. The study focuses on the effects of these fertilizers on the mineral forms of nitrogen content and the size of N2O emissions from the soil. When applying leaf treatments of mineral and bioorganic fertilizers to cultivated crops, the nitrogen content in light sierozems is enhanced. The main sources of nutrition are easily hydrolyzable and nitrate nitrogen, which accounts for more than 80 %. The contribution of ammonium forms to plant nutrition is insignificant. The size of nitrous oxide emissions was recorded at the beginning of the experiment and after the initial leaf treatment. Under winter wheat crops, the initial concentration of nitrous oxide was 440.3 µg/m³. In the field prepared for sowing sugar beet and soybean in 2023, the concentrations were 373.7 µg/m³ and 557.7 µg/m³, respectively. After the initial treatment, the vegetation on the leaves showed that, on average, the indicator in the different experimental variants for winter wheat crops was 679 µg/m³, for sugar beet crops was 576.8 µg/m³, and for soybean crops was 637.2 µg/ m³. In agroecosystems, N2O emissions are higher under winter wheat compared to row crops such as sugar beet and soybean.
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Hellmuth, Rebecca, e George Hochmuth. "Managing Nitrogen Inputs and Outputs on a Dairy Farm". EDIS 2015, n. 3 (6 maggio 2015): 5. http://dx.doi.org/10.32473/edis-ss640-2015.
Testo completoAbstract (sommario):
In dairy production systems, nitrogen flows through both the forage crops and the dairy cows. Forage crops use nitrogen mineralized from manure for plant growth. Harvested crops are then fed to dairy cows that, in turn, use the nitrogen for their growth and milk production. When the cows excrete a portion of the consumed nitrogen as manure the cycle is renewed. This 5-page fact sheet focuses on the forage production aspect of the nitrogen cycle at a dairy farm. Written by Rebecca Hellmuth and George Hochmuth, and published by the UF Department of Soil and Water Science, March 2015. (Image credit: R. Hellmuth) SL427/SS640: Managing Nitrogen Inputs and Outputs on a Dairy Farm (ufl.edu)
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Hellebrand, H. J., V. Scholz e J. Kern. "Nitrogen conversion and nitrous oxide hot spots in energy crop cultivation". Research in Agricultural Engineering 54, No. 2 (24 giugno 2008): 58–67. http://dx.doi.org/10.17221/1001-rae.
Testo completoAbstract (sommario):
Since 1999, nitrous oxide (N<sub>2</sub>O) soil emissions from sites cultivated with energy plants have been measured by gas chromatography and gas flux chambers in experimental fields. The main aim of this study was the nitrogen conversion factor and its variability for sandy soils under climatic conditions of Central Europe. Annual plants (hemp, rape, rye, sorghum, triticale) and perennial plants (grass, perennial rye, poplar, willow) were fertilised with three different levels of nitrogen (150 kg N/ha/year, 75 kg N/ha/year, and none). The annual nitrogen conversion factors were derived from the annual mean differences between the fertilised sites and non-fertilised control sites. The mean nitrogen conversion factor for the non-cultivated soils was lower (perennial crops: 0.4%) than that for the regularly cultivated soils (annual crops: 0.9%). Few times, enhanced N<sub>2</sub>O emission spots with maxima above 1000 μ<sub>2</sub>O/m<sup>2</sup>/h, lasting for several weeks, were observed in the course of measurements. The influence of these local peak emissions on the nitrogen conversion factor is discussed.
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Lupwayi, Newton Z., e Yoong K. Soon. "Nitrogen-Related Rotational Effects of Legume Crops on Three Consecutive Subsequent Crops". Soil Science Society of America Journal 80, n. 2 (marzo 2016): 306–16. http://dx.doi.org/10.2136/sssaj2015.08.0299.
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Cocking, Edward, e David Dent. "The prospect of N2-fixing crops galore!" Biochemist 41, n. 4 (1 agosto 2019): 14–17. http://dx.doi.org/10.1042/bio04104014.
Testo completoAbstract (sommario):
The impact of carbon on our climate has been of major concern for a number of years. However, we are now learning to be equally concerned about the next element in the periodic table, nitrogen, and the consequences of using synthetic nitrogen fertilizers in agriculture that pollute our planet and its atmosphere.
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Colangelo, David J., e Mark H. Brand. "Water and Nitrogen Management to Reduce Nitrate-Nitrogen Leaching from Container Crops". HortScience 32, n. 3 (giugno 1997): 455E—455. http://dx.doi.org/10.21273/hortsci.32.3.455e.
Testo completoAbstract (sommario):
Plastic 208-L industrial barrels (14 total) were modified for use as soil-filled lysimeters to study the nitrogen dynamics of a typical container crop production system. The top of each barrel was removed and the bottom was fitted with a drain hole and filter fabric. The drain was then connected via tubing to a 2-L leachate collection vessel made from a length of 15.24-cm-diameter PVC pipe that had been capped on one end. All barrels and connected collection vessels were recessed into a grassed slope. Barrels were filled with homogeneous B and C horizon soil to simulate soil conditions of a typical container nursery. Uniform Rhododendron `Catawbiense Album' plants in 4.5-L containers were arranged atop the barrellysimeters at four plants per barrel. Irrigation/fertilizer treatments included fertilized pulse trickle irrigation (four replications), fertilized overhead irrigation (four replications), and unfertilized controls corresponding to each irrigation treatment (three replications each). All fertilized plants received 10 g of 17N–6P–10K 8- to 9-month controlled-release fertilizer at the beginning of the crop cycle. Leachate from the barrel-lysimeters was collected weekly and total volume, total Kjeldahl N, nitrate-N, and ammonium-N were determined. Peak nitrate-N levels were well above the current drinking water standard for both irrigation treatments at certain times during the year. Cumulative nitrate-N mass output was similar for both irrigation treatments. A nitrogen balance for the complete production system including fertilizer and irrigation water input, plant material, potting media, soil in the lysimeter barrels and leachate output from the barrels has also been determined.
34
Stevenson, F. C., e C. van Kessel. "The nitrogen and non-nitrogen rotation benefits of pea to succeeding crops". Canadian Journal of Plant Science 76, n. 4 (1 ottobre 1996): 735–45. http://dx.doi.org/10.4141/cjps96-126.
Testo completoAbstract (sommario):
The inclusion of a pulse crop in a rotation often leads to greater seed yields in the succeeding cereal crop. Two rotations were established at three sites in 1993 to examine the N and non-N rotation benefits of pea (Pisum sativum L.) to the subsequent wheat (Triticum aestivum L.) then oilseed crops. Wheat seed yield was 43% greater (rotation benefit) when preceded by pea rather than wheat, a consistent response among sites. Six to fourteen kg ha−1 of the extra 27 kg ha−1 of N accumulated by wheat in the pea–wheat rotation was derived from the additional N derived from pea residue. The additional soil N availability in the pea–wheat rotation, as indicated by the A-value, explained 8% of the rotation effect on seed yield (N benefit). The remaining 92% of the yield advantage in the pea–wheat rotation was attributed to non-N rotation benefit. The yield of the oilseed crop following the pea–wheat phase of the rotation did not differ from that following the wheat–wheat phase. The influence of growing conditions and cropping history on the magnitude of the N to non-N rotation benefits, and the contribution of different non-N effects, should be investigated further. Key words: Rotation benefit, pea, wheat, residue N, non-N benefit
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PADHAN, BIRENDRA KUMAR, LEKSHMY SATHEE e VANITA JAIN. "Nitrogen remobilization and its importance in nitrogen use efficiency (NUE) of crops". Indian Journal of Agricultural Sciences 90, n. 12 (10 febbraio 2021): 2251–61. http://dx.doi.org/10.56093/ijas.v90i12.110299.
Testo completoAbstract (sommario):
Nitrogen (N) remobilization during grain filling from pre-anthesis N uptake and stored in different tissues of crop N use efficiency (NUE). N is remobilized from to sink (young leaves or grains) with the help of nitrate/amino acid transporters. Nearly 80% of grain N in cereals is derived from N remobilized from vegetative tissues. Remobilization of N within the plant takes place from older leaves to young leaves, leaves to grains, senescing organs to grains, from storage parts to grains. Enzymes involved in N remobilization include glutamine synthetase (GS), glutamate dehydrogenase (GDH), asparagine synthetase (AS) and proteases. Among them, cytosolic GS plays a key role during N remobilization in cereals. There are various senescence-associated genes (SAG) involved in N remobilization from older degrading leaves to younger leaves and grains. Autophagy (ATG) is an important mechanism involved in the degradation of stored N in the form of various proteins to amino acids, which are transported to long-distance in the form of glutamine and asparagine via phloem tissue. There is a complex network of genes, mechanisms, and factors associated with N remobilization, which needs to be considered for improving NUE of crops.
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Козырева, М. Ю., e Л. Ж. Басиева. "THE NITROGEN CONSUMPTION BY ALFALFA CROPS DEPENDING ON THE NITROGEN NUTRITION PATTERN". Niva Povolzh`ia, n. 3(56) (17 dicembre 2020): 50–56. http://dx.doi.org/10.36461/np.2020.56.3.015.
Testo completoAbstract (sommario):
Приведены результаты полевых исследований потребления азота посевами люцерны в зависимости от режима азотного питания и симбиотической активности посевов за 2017…2019 годы. Опыты с люцерной синегибридной проведены в экологических условиях предгорной зоны РСО-Алания на черноземе выщелоченном с близким залеганием галечника. Сравнивались минеральный и симбиотрофный режимы азотного питания растений люцерны. Установлено, что в год посева потребление азота посевами люцерны составило от 105,0 до 135,4 кг/га, при этом к первому укосу потребление было в 1,1…1,2 раза больше, чем ко второму укосу. На второй и третий годы пользования посевами потребление азота выросло в 1,7…1,9 раза в сравнении с показателями года посева. Показатели вариантов с естественными условиями (контроль) и внесением стартовых доз азотных удобрений (N30) были практически идентичными. Показатели вариантов с инокуляцией семян высокогорным инокулюмом (Ин-1800) и внесением стартовых доз азотных удобрений на фоне инокуляции (N30 + Ин) во второй и третий годы пользования посевами были практически идентичными. Объемы потребления азота в указанных вариантах составили свыше 235 кг/га, или на 25,6…27,1 % выше показателей контрольного варианта. В сумме за три года исследований посевы люцерны в контрольном варианте усвоили 483,3 кг/га азота. Стартовые дозы азотных удобрений (N30) увеличили данный показатель всего на 1,4 %. Предпосевная инокуляция семян способствовала увеличению потребления азота во всех вариантах: в варианте с промышленным штаммом ризоторфина (Шт. 425а) – на 17,8 %, с высокогорным инокулюмом на фоне внесения стартовых доз минеральных азотных удобрений (N30 + Ин) – на 24,6 %, с высокогорным инокулюмом в чистом виде (Ин-1800) – на 27,1 %. Ключевые слова: люцерна, режим питания, симбиотическая активность, минеральный азот, биологический азот, потребление азота. The results of field studies of nitrogen consumption in alfalfa crops depending on the nitrogen nutrition pattern and symbiotic activity of crops for 2017...2019 are presented. Experiments with the alfalfa purple were carried out in the ecological conditions of the foothill zone of the North Ossetia-Alania, on leached chernozem with a close occurrence of gravel. Mineral and symbiotrophic patterns of nitrogen nutrition of alfalfa plants were compared. It was found that in the year of planting, the nitrogen consumption of alfalfa crops ranged from 105.0 to 135.4 kg/ha, and by the first mowing, the consumption was 1.1...1.2 times bigger than by the second mowing. In the second and third years of crop use, nitrogen consumption increased by 1.7...1.9 times compared to the year of planting. The parameters of the options with natural conditions (control) and the addition of starting doses of nitrogen fertilizers (N30) were almost identical. In the second and third years of use of crops, parameters of options with inoculation of seeds with high-altitude inoculum (In-1800) and the addition of starting doses of nitrogen fertilizers within the background of inoculation (N30 + in) were almost identical. In these options, the amount of nitrogen consumption was more than 235 kg/ha, or 25.6...27.1 % higher than in the control variant. In total, over three years of research, in the control option alfalfa crops took 483.3 kg/ha of nitrogen. Starting doses of nitrogen fertilizers (N30) increased this indicator by only 1.4 %. Pre-planting inoculation of seeds contributed to an increase in nitrogen consumption in all options: in the option with the industrial strain of risotorphine (St. 425a) – by 17.8 %, with high-altitude inoculum within the background of adding starting doses of mineral nitrogen fertilizers (N30 + In) – by 24.6 %, with high-altitude inoculum in pure form (In-1800) – by 27.1 %.
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Padilla, Francisco M., Michela Farneselli, Giorgio Gianquinto, Francesco Tei e Rodney B. Thompson. "Monitoring nitrogen status of vegetable crops and soils for optimal nitrogen management". Agricultural Water Management 241 (novembre 2020): 106356. http://dx.doi.org/10.1016/j.agwat.2020.106356.
Testo completo
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Tkachuk, Oleksander, e Vitalii Ovcharuk. "ECOLOGICAL POTENTIAL OF GRAIN PEGULUM CROPS IN MODERN INTENSIVE CROP ROTATIONS". Agriculture and Forestry, n. 3 (30 ottobre 2020): 161–71. http://dx.doi.org/10.37128/2707-5826-2020-3-14.
Testo completoAbstract (sommario):
The article discusses the ecological significance of leguminous crops grown in modern intensive crop rotation. In particular, the area under crops of common leguminous crops in Ukraine and the level of their productivity have been analyzed. A comparison is made with the acreage of the most widespread grain crops. The emphasis of the article is aimed at establishing the level of nitrogen fixation of leguminous crops, which have the largest sown areas in Ukraine. The volume of accumulation by these leguminous crops of by-products in the form of their straw and stubble is also calculated. A comparison is made according to these indicators with the most widespread grain crops grown in Ukraine. The data on the content of the main nutrients in the by-products of leguminous crops - nitrogen, phosphorus, potassium are given. On the basis of these indicators, a calculation was made of the accumulation of the main nutrients in the soil, which can come with the by-products of leguminous crops with an average yield of their seeds. We also compared the obtained indicators with the input of nitrogen, phosphorus and potassium into the soil with by-products of the most common grain crops. Based on this, a conclusion was made about the most effective leguminous crops, the cultivation of which in the modern intensive crop rotation contributes most to the stabilization of the agro-ecological state of the soil. According to the State Statistics Service in Ukraine in 2019, the largest sown area among leguminous crops belonged to peas - 347.0 thousand hectares, which is 61.3% in the structure of all leguminous crops. In total, the sown area for leguminous crops in Ukraine is 566.0 thousand hectares, which is about 2% of the total sown area and this is a very low indicator. Considering the average yield in Ukraine, beans can return more by-products to the soil - 3.5 t/ha, soybeans and peas - by 8.6% less, beans - by 37.1%, and least of all - chickpeas and lentils - 1.7 - 1.8 t/ha. The content of the main macronutrients in the by-products of all leguminous crops is similar and is: nitrogen - 10.0-12.0 kg/t, phosphorus - 3.4-3.6 kg/t, potassium - 4.6-5.0 kg/t. It has been proven that an increase in the area of leguminous crops in an intensive crop rotation will have a positive effect on the agro-ecological state of the soil. In particular, growing beans allows you to get the highest mass of by-products that can be ploughed into the soil - 3.5 t/ha. Also, by-products of beans are characterized by a high content of mineral phosphorus - 3.6 kg/t, which ensures the supply of all mineral phosphorus to the soil - 12.6 kg/ha of all leguminous crops, as well as potassium - 16.5 kg/ha. Soybean by-products are characterized by a high nitrogen content - 12.0 kg/t, phosphorus - 3.6 kg/t and potassium - 5.0 kg/t. This allows, after growing soybeans, to accumulate in the soil with by-products more mineral nitrogen - 38.4 kg/ha. Also, soybeans are characterized by a high symbiotic nitrogen-fixing ability among all leguminous crops - 120 kg/ha. By-products of leguminous crops have a high content of nitrogen - 2.3-2.7 times, phosphorus - 1.5-1.6 times compared to by-products of grain crops. Also, when plowing soybean by-products into the soil, there will be 2 times more mineral nitrogen and 1.1-1.3 times more phosphorus than when plowing winter wheat by-products. Key words: egumes, by-products, nitrogen fixation, nutrients, accumulation, soil.
39
Haider, Tazeem, Muhammad Shahid Farid, Rashid Mahmood, Areeba Ilyas, Muhammad Hassan Khan, Sakeena Tul-Ain Haider, Muhammad Hamid Chaudhry e Mehreen Gul. "A Computer-Vision-Based Approach for Nitrogen Content Estimation in Plant Leaves". Agriculture 11, n. 8 (11 agosto 2021): 766. http://dx.doi.org/10.3390/agriculture11080766.
Testo completoAbstract (sommario):
Nitrogen is an essential nutrient element required for optimum crop growth and yield. If a specific amount of nitrogen is not applied to crops, their yield is affected. Estimation of nitrogen level in crops is momentous to decide the nitrogen fertilization in crops. The amount of nitrogen in crops is measured through different techniques, including visual inspection of leaf color and texture and by laboratory analysis of plant leaves. Laboratory analysis-based techniques are more accurate than visual inspection, but they are costly, time-consuming, and require skilled laboratorian and precise equipment. Therefore, computer-based systems are required to estimate the amount of nitrogen in field crops. In this paper, a computer vision-based solution is introduced to solve this problem as well as to help farmers by providing an easier, cheaper, and faster approach for measuring nitrogen deficiency in crops. The system takes an image of the crop leaf as input and estimates the amount of nitrogen in it. The image is captured by placing the leaf on a specially designed slate that contains the reference green and yellow colors for that crop. The proposed algorithm automatically extracts the leaf from the image and computes its color similarity with the reference colors. In particular, we define a green color value (GCV) index from this analysis, which serves as a nitrogen indicator. We also present an evaluation of different color distance models to find a model able to accurately capture the color differences. The performance of the proposed system is evaluated on a Spinacia oleracea dataset. The results of the proposed system and laboratory analysis are highly correlated, which shows the effectiveness of the proposed system.
40
Zhuang, Hua, e Ying Wang. "Effects of Nitrogen Reduction Combined with Organic Fertilizer on Crops". Frontiers in Science and Engineering 4, n. 5 (22 maggio 2024): 112–17. http://dx.doi.org/10.54691/27py1d57.
Testo completoAbstract (sommario):
By summarizing the methods of nitrogen fertilizer reduction combined with organic fertilizer, this paper discussed and analyzed the effects of nitrogen fertilizer reduction combined with organic fertilizer on soil carbon and nitrogen content and biological activity of crops, mastered the soil carbon and nitrogen retention capacity of orchards, clarified the relationship between fruit trees and soil environment, and established the optimal effect equation between fertilizer application and yield. It is of great scientific significance to provide theoretical basis and technical support for optimizing fertilizer application in orchards and realizing "zero growth" and "double reduction" of nitrogen fertilizer.
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Oda, Masato, e Uchada Sukchan. "Crop production under nitrogen starvation conditions: relationships with applied organic matter and soil microbial biomass". F1000Research 9 (7 febbraio 2020): 90. http://dx.doi.org/10.12688/f1000research.21814.1.
Testo completoAbstract (sommario):
Background: The application of organic matter with a high C/N ratio is effective for the prevention of soil degradation, although this can cause nitrogen starvation. However, some fields are highly productive under nitrogen-starvation conditions. The underlying mechanisms for this are unclear but the correlation between soil microbial biomass (SMB) and crop yield suggests that nitrogen flows from SMB to crops. We aimed to clarify this flow and the source of nitrogen. Methods: We achieved nitrogen starvation conditions by applying waste mushroom bed and repeated lettuce cropping with different crop management practices, such as watering and fertilizer application. We analyzed correlations among crop yield, SMB, and total nitrogen. Results: The order of the lettuce yield stably corresponded with the management practice used. The SMB increased remarkably by the time of the second lettuce cropping and showed a strong correlation with crop yield. The nitrogen from the waste mushroom bed was lost by denitrification. The rate of decomposition showed no correlation with yield or SMB. Conclusions/Discussions: The crop yield corresponded with the management practice earlier than SMB. Namely, no nitrogen flow from SMB affected the crops. Furthermore, most applied nitrogen was denitrified, so the nitrogen flows of applied organic matter, SMB, and crops are independent. Therefore, the nitrogen source of both SMB and crops is biological fixation. The correlation between SMB and crop yield is not a causal relationship. The nitrogen source for both is nitrogen fixation. The application of organic matter enhances this by occurring nitrogen starvation but not providing a nitrogen source.
42
PAMPANA, SILVIA, ALESSANDRO MASONI, MARCO MARIOTTI, LAURA ERCOLI e IDUNA ARDUINI. "NITROGEN FIXATION OF GRAIN LEGUMES DIFFERS IN RESPONSE TO NITROGEN FERTILISATION". Experimental Agriculture 54, n. 1 (11 ottobre 2016): 66–82. http://dx.doi.org/10.1017/s0014479716000685.
Testo completoAbstract (sommario):
SUMMARYLegume crops are not usually fertilised with mineral N. However, there are at least two agronomic cases when it would be advantageous to distribute N fertiliser to legume crops: at sowing, before the onset of nodule functioning, and when a legume is intercropped with a cereal. We highlight the impact of various levels of fertiliser nitrogen on grain yield, nodulation capacity and biological nitrogen fixation in the four most common grain legume crops grown in central Italy. Chickpea (Cicer arietinum L.), field bean (Vicia faba L. var. minor), pea (Pisum sativum L.) and white lupin (Lupinus albus L.) were grown in soil inside growth boxes for two cropping seasons with five nitrogen fertilisation rates: 0, 40, 80, 120 and 160 kg ha−1. In both years, experimental treatments (five crops and five levels of N) were arranged in a randomised block design. We found that unfertilised plants overall yielded grain, total biomass and nitrogen at a similar level to plants supplied with 80–120 kg ha−1 of mineral nitrogen. However, above those N rates, the production of chickpea, pea and white lupin decreased, thus indicating that the high supply of N fertiliser decreased the level of N2 fixed to such an extent that the full N2-fixing potential might not be achieved. In all four grain legumes, the amount of N2 fixed was positively related to nodule biomass, which was inversely related to the rate of the N fertiliser applied. The four grain legumes studied responded differently to N fertilisation: in white lupin and chickpea, the amount of nitrogen derived from N2 fixation linearly decreased with increasing N supply as a result of a reduction in nodulation and N2 fixed per unit mass of nodules. Conversely, in field bean and pea, the decrease in N2 fixation was only due to a reduction in nodule biomass since nodule fixation activity increased with N supply. Our results suggest that the legume species and the N rate are critical factors in determining symbiotic N2-fixation responses to N fertilisation.
43
Sainju, U. M., B. P. Singh e W. F. Whitehead. "Cover crops and nitrogen fertilization effects on soil carbon and nitrogen and tomato yield". Canadian Journal of Soil Science 80, n. 3 (1 agosto 2000): 523–32. http://dx.doi.org/10.4141/s99-107.
Testo completoAbstract (sommario):
Cover crops can influence soil properties and crop yield. We examined the influence of legume [hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.)] and nonlegume [rye (Secale cereale L.)] cover crops and N fertilization (0, 90, and 180 kg N ha−1) on the short- and long-term effects on soil C and N and tomato yield and N uptake. We measured organic C and N (long-term effects), potential C and N mineralization (PCM and PNM) and inorganic N (short-term effects) periodically on a Greenville fine sandy loam (fine-loamy, kaolinitic, thermic, Rhodic Kandiudults) planted with tomato (Lycopersicum esculentum Mill) from April to August in 1996 and 1997 in Georgia USA. Soil C and N concentrations increased early in the growing season with cover crop residue incorporation, but decreased as the residue decomposed. Rye increased organic N and maintained greater levels of organic C and PCM after 3 yr than other treatments. In contrast, hairy vetch and crimson clover increased PNM and inorganic N soon after residue incorporation into the soil and produced tomato yield and N uptake similar to that produced by 90 and 180 kg N ha–1. Nitrogen fertilization increased PNM and inorganic N after split application and tomato yield and N uptake but decreased organic C and N and PCM compared with rye. Compared with 0 kg N ha–1, nonlegume cover crops, such as rye can increase organic C and N and PCM but legume cover crops, such as hairy vetch and crimson clover, can enrich soil N and produce tomato yield and N uptake similar to that produced by 90 and 180 kg N ha−1. Key words: Cover crops, nitrogen fertilization, soil carbon, soil nitrogen, tomato yield
44
RAMAZANOVA, SB, SB KENENBAYEV, VN GUSEV e GSH BAYMAKANOVA. "NITROGEN FERTILIZERS ROLE IN GRAIN CROPS PRODUCTIVITY IN SOUTH-EAST KAZAKHSTAN". SABRAO Journal of Breeding and Genetics 55, n. 5 (31 ottobre 2023): 1812–20. http://dx.doi.org/10.54910/sabrao2023.55.5.32.
Testo completoAbstract (sommario):
Seeking to improve the efficiency of nitrogen fertilizers for grain crops led to conducting this study on developing methods using 15N in 2015–2017 at the Kazakh Research Institute of Agriculture, Almalybak Village, Almaty Region, Southeastern Kazakhstan. Nitrogen use efficiency using the stable isotope 15N in microfield experiments revealed that the assimilation of nitrogen fertilizers by grain crops largely depends on the norms, timing, fertilization method, and varietal parameters of the concerned crop. Based on morphophysiological methods of monitoring plant development conditions, the nitrogen fertilizers’ role based on the development has been affirmative, with the optimal timing of their application also determined. Results show that grain crops use nitrogen productively with partial application at the beginning of tillering and tubing, respectively, and stages III and V of organogenesis. With the use of nitrogen fertilizers, the significant varietal differences were evident. The help of an isotope label established the accurate nitrogen utilization coefficients of fertilizers based on the options ranging from 14.7% to 32.2%. Using the isotope method provides an opportunity for further development of practicing the most efficient techniques of applying fertilizers, which is an imperative method for determining the effectiveness of nitrogen fertilizers.
45
Braos, Lucas Boscov, Roberta Souto Carlos, Aline Carla Trombeta Bettiol, Marina Ali Mere Bergamasco, Maira Caroline Terçariol, Manoel Evaristo Ferreira e Mara Cristina Pessôa da Cruz. "Soil Carbon and Nitrogen Forms and Their Relationship with Nitrogen Availability Affected by Cover Crop Species and Nitrogen Fertilizer Doses". Nitrogen 4, n. 1 (13 febbraio 2023): 85–101. http://dx.doi.org/10.3390/nitrogen4010007.
Testo completoAbstract (sommario):
Cover crops and N fertilization strongly impact the forms of soil organic C and N and their availability, which change the responses of plants to N fertilization and soil organic C accumulation. Our study objectives were to evaluate the effects of cover crops and N doses on soil total and soluble C and N contents, N fractions, and potentially available N in a long-term no-till experiment. The experiment was conducted in a randomized block design with split plots and four replicates. The main treatments were cover crops species, jack bean, lablab bean, millet, velvet bean, and fallow cultivated prior to maize. Secondary treatments included two doses of mineral N (0 and 120 kg ha−1). Soil samples were collected at depths of 0–5, 5–10, 10–20, and 20–40 cm, which were analyzed for total and water-soluble C and N contents, N fractions (acid hydrolysis method), and potentially available N (hot KCl solution and direct steam distillation methods). Cover crop velvet bean resulted in the highest soil organic carbon levels, and cover crop millet plus fertilization resulted in the highest levels of soil total N. The amino sugar was the largest N fraction, which decreased by 8% with N fertilization. The soluble C and N content strongly correlated with total and available N content. The changes in soil N were influenced by cover crop species and fertilization and the interactions of both, so the combination of fertilization regime and cover crops must be chosen with care. Additionally, legumes are a good source of plant and soil N in systems with low input of N via fertilizer; however, the combination of N fertilizer with legumes can reduce soil N reserves, leading to its long-term depletion.
46
Crews, T. E. "Perennial crops and endogenous nutrient supplies". Renewable Agriculture and Food Systems 20, n. 1 (marzo 2005): 25–37. http://dx.doi.org/10.1079/raf200497.
Testo completoAbstract (sommario):
AbstractPerennial cropping systems may achieve significant improvement over annual systems in the synchrony between crop nutrient demands and nutrient supplies. Improvements in nutrient synchrony would result in the reduction of nutrient losses and their associated environmental impacts. A perennial system with high levels of synchrony would also require fewer nutrient inputs, such that it may be possible to develop an agriculture that functions mostly, if not entirely, on nutrient inputs from endogenous sources (i.e., weathering of primary and secondary minerals and biological nitrogen fixation). In this paper I describe three realms of research that will inform the development of relatively high-yielding grain production systems grown on endogenous nutrient supplies: (1) improvement of nutrient synchrony through the development of perennial crops; (2) identification of soils that are in a high nutrient release phase of pedogenesis, which could balance the export of rock-derived nutrients in crop harvests; and (3) optimization of legume density, harvest index and percent nitrogen derived from the atmosphere (%Ndfa) to achieve adequate nitrogen inputs through biological fixation.
47
Pszczółkowska, Agnieszka, Adam Okorski, Jacek Olszewski, Gabriel Fordoński, Sławomir Krzebietke e Alina Chareńska. "Effects of pre-preceding leguminous crops on yield and chemical composition of winter wheat grain". Plant, Soil and Environment 64, No. 12 (30 novembre 2018): 592–96. http://dx.doi.org/10.17221/340/2018-pse.
Testo completoAbstract (sommario):
The after-effects of pre-preceding crops (second year), i.e. legumes and spring wheat, and nitrogen fertilization rate (0, 60, 120 and 180 kg N/ha) on the yield and chemical composition of winter wheat grain were analysed in a field experiment conducted in 2013–2015. Winter wheat was characterized by higher yield when sown after blue lupine (increase of 0.23 t/ha) and faba beans with a determinate growth habit (increase of 0.37 t/ha) than after spring wheat. Grain yield increased significantly with a rise in nitrogen fertilization rate (by 2.03, 3.47 and 4.02 t/ha, respectively). The species of pre-preceding crops had no significant effect on the phosphorus, potassium, magnesium and calcium content of winter wheat grain. Winter wheat grown after faba beans with an indeterminate growth habit was most abundant in nitrogen. The applied nitrogen fertilizer rates did not modify the concentrations of phosphorus, magnesium and calcium in winter wheat grain. The nitrogen content of grain increased significantly with a rise in nitrogen fertilization rates. A significant increase in manganese and zinc levels was observed when spring wheat was the pre-preceding crop and the iron content of grain increased significantly when winter wheat was grown after peas and blue lupine.
48
Vlasenko, O. A. "DYNAMICS OF NUTRITION ELEMENTS IN FODDER CROPS AGROCENOUSES". Mongolian Journal of Agricultural Sciences 21, n. 02 (6 febbraio 2018): 75–77. http://dx.doi.org/10.5564/mjas.v21i02.910.
Testo completoAbstract (sommario):
Rapeseed and rapeseed and millet mixtures are cultivated, the supply of chernozem with nitrate nitrogen is low and medium, the supply of ammonium nitrogen is high. The availability of mobile phosphorus is reduced by the end of the growing season. The availability of exchange potassium for these crops is very high.
49
Angus, J. F., e P. R. Grace. "Nitrogen balance in Australia and nitrogen use efficiency on Australian farms". Soil Research 55, n. 6 (2017): 435. http://dx.doi.org/10.1071/sr16325.
Testo completoAbstract (sommario):
The amount of reactive N in soils on the Australian continent appears to be increasing, mainly because of biological N-fixation by permanent pastures in the dryland farming zone. This gain is partly offset by N-mining by crops, which we estimate have removed between one-fifth and one-quarter of the original soil N. The vast areas of non-agricultural land and arid rangelands appear to be in neutral N balance and the relatively small area of intensive agriculture is in negative balance. There are regional N losses from the sugar and dairy industries to groundwater, estuaries and lagoons, including the Great Barrier Reef. Fertiliser N application is increasing, and is likely to increase further, to compensate for the soil-N mining and to meet increasing crop yield potential, but fertiliser-N represents a relatively small fraction of the Australian N balance. The dryland farming zone utilises the largest amounts of native and fertiliser N. The average fertiliser application to dryland cereals and oilseeds, 45 kg N ha–1, is low by international standards because of the small N-demand by dryland crops and because there are no subsidies on crops or fertiliser that promote overuse. The efficiency of N-use is relatively low, for example about 40% of fertiliser N is recovered in the aboveground parts of dryland wheat and the rest is retained in the soil, denitrified or otherwise lost. We suggest further research on fertiliser-application methods to increase crop recovery of fertiliser, as well as research to reduce the surplus N from permanent pasture.
50
Branco, Roberto BF, Sally F. Blat, Tais GS Gimenes, Rodrigo HD Nowaki, Humberto S. Araújo e Fernando A. Salles. "Nitrogen fertilization of vegetables cultivated under no-tillage after cover crops". Horticultura Brasileira 35, n. 1 (marzo 2017): 103–10. http://dx.doi.org/10.1590/s0102-053620170116.
Testo completoAbstract (sommario):
ABSTRACT The production of horticultural crops in no-tillage and in rotation with cover crops reduces the dependency in nitrogen fertilizer, due to increased soil organic matter and by biological fixation performed by legumes. Thus, the aim of this work was to study rates of nitrogen fertilization and cover crops in the agronomic performance of tomato and broccoli grown under no-tillage. The experiment was conducted in a split plot design with four replications. Treatments consisted of cover crops, sunn hemp and millet, and four rates of nitrogen fertilization (0, 50, 100 and 200 kg/ha of nitrogen), for both the tomato and broccoli crops. All soil management was performed in no-tillage. For tomato crops we evaluated the plant growth, the nitrate concentration of sprouts and fruits and yield of commercial and non commercial fruits. For broccoli we evaluated plant growth and yield. There was an interaction effect between cover crop and nitrogen rates to tomato growth measured at 100 days after transplanting, for plant height, number of fruit bunches, dry mass of leaves and diameter of the stalk. The tomato commercial fruit number and yield showed maximum values with 137 and 134 kg/ha of N respectively, on the sunn hemp straw. The nitrate concentration of the tomato sprouts was linearly increasing with the increase of nitrogen rates, when grown on the millet straw. For broccoli production, the maximum fresh mass of commercial inflorescence was with 96 kg/ha of N, when grown on the millet straw.