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Ma, Qifu, Zed Rengel i Terry Rose. "The effectiveness of deep placement of fertilisers is determined by crop species and edaphic conditions in Mediterranean-type environments: a review". Soil Research 47, nr 1 (2009): 19. http://dx.doi.org/10.1071/sr08105.
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Much of our knowledge of plant growth in response to soil nutrient supply comes from studies under homogeneous soil conditions. However, the adoption of reduced or nil tillage and shallow banding of fertilisers at the time of seeding causes spatially variable distribution and availability of soil nutrients in agricultural lands. Soil available nutrients, particularly the poorly mobile ones such as phosphorus (P), potassium (K), zinc (Zn), manganese (Mn), and copper (Cu), stratify within the fertilised topsoil. In water-limited environments where the topsoil is prone to drying, soil nutrient stratification may influence nutrient availability and plant uptake because of impeded root growth or reduced diffusion of immobile nutrients to the root surface, or more likely a combination of both factors. Placing fertilisers deeper in the soil profile could increase nutrient acquisition and utilisation by plants as fertiliser nutrients are in the moist soil for a longer part of the growing season. However, the effectiveness of deep placement of fertilisers may also be determined by soil texture, tillage, fertilising history, nutrient mobility, and crop species. In Mediterranean-type climates of southern Australia, a yield response of winter crops to deep fertiliser mostly occurs on infertile sandy soils in low rainfall regions. This contrasts with the responses of winter and summer crops in northern Australia on soils with optimum-to-high nutrients but subjected to rapid and frequent drying of topsoil because of high temperatures and high evaporation demand during the growing season. The pattern of nutrient accumulation by crop species (indeterminate v. determinate) and the mobility of mineral nutrients in the phloem would also modify the effectiveness of deep-placed nutrients under drought. The complexity of plant responses to subsoil nutrition may suggest that before adopting deep fertiliser practice in a paddock it is essential to understand the effects of edaphic and climatic conditions, soil management, and plant–soil interactions in order to achieve maximum yield benefit.
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Yang, Z. P., D. A. Turner, J. J. Zhang, Y. L. Wang, M. C. Chen, Q. Zhang, O. T. Denmead, D. Chen i J. R. Freney. "Loss of nitrogen by ammonia volatilisation and denitrification after application of urea to maize in Shanxi Province, China". Soil Research 49, nr 5 (2011): 462. http://dx.doi.org/10.1071/sr11107.
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Much of the fertiliser nitrogen (N) used in agriculture is lost to the atmosphere as nitric oxide and nitrogen dioxide (collectively referred to as NOx), ammonia (NH3), and nitrous oxide (N2O). The lost N is not only an economic problem for the farmer; it also contaminates the environment and affects human health. Because the values obtained for NOx and NH3 loss to the atmosphere from agriculture in Monsoon Asia have been questioned, we quantitatively determined, using new techniques, the emission of these gases from a maize crop fertilised with urea in northern China. The fertiliser was deep-placed by traditional farmers’ practice and emissions of NOx and NH3were determined with a chemiluminescence analyser and a backward Lagrangian stochastic dispersion technique. The emission measurements indicate that 1.2% of the applied N was lost as NOx. This loss is far greater than measured or derived by other researchers, and we suggest that this is because our measurements were made continuously rather than as spot measurements with static chambers. The results for NH3 show that, although the fertiliser was placed below the soil surface, a small amount (7% of the applied N) was still lost to the atmosphere. Soil analyses indicate that the rate of nitrification in this soil was low, and the maximum nitrate (NO3–) concentration found in the soil (31.4 µg N/g) was only 3.9% of the fertiliser N added. Thus, there is little potential for NO3– to be leached down the profile. A study using soil cores and acetylene inhibition to measure denitrifying activity suggested that the rate of denitrification in this soil was also very low. The results suggest that in this soil with slow nitrification and denitrification rates and little potential for leaching, deep placement of the urea to limit NH3 volatilisation is an effective method for increasing fertiliser use efficiency.
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Bolland, M. D. A., i R. F. Brennan. "Phosphorus, copper and zinc requirements of no-till wheat crops and methods of collecting soil samples for soil testing". Australian Journal of Experimental Agriculture 46, nr 8 (2006): 1051. http://dx.doi.org/10.1071/ea05024.
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Plant testing of wheat crops in south-western Australia, sown using no-till for >7 years, often indicates marginal to deficient levels of the soil immobile elements phosphorus (P), copper (Cu) and zinc (Zn). In this region, P, Cu and Zn fertilisers are usually placed (drilled) with the seed while sowing crops. However, in no-till cropping, because the fertilisers are placed in the same rows as the seed during sowing, in the years after application the 3 elements are no longer mixed through the top 10 cm of soil. It may be more effective to deep band fertiliser below seed while sowing no-till crops. Alternatively, cultivating the top 10 cm of soil every 5–7 years would mix previously applied fertiliser P, Cu and Zn through the topsoil, which should improve the effectiveness of the fertiliser residues for the current and subsequent no-till crops. In field experiments in paddocks in south-western Australia sown using no-till for 7–11 years, we compared these 2 alternative methods to the standard no-till practice of drilling fertiliser with the seed in the same crop rows. No shoot or grain yield responses of wheat were obtained. The exception was that in 1 experiment cultivating the topsoil before drilling P with seed was more effective than drilling or deep banding P. Concentrations of P, Cu and Zn measured in wheat shoots or grain were either unaffected by treatment, or, compared with drilling fertiliser with seed, were larger for the other 2 methods, indicating these 2 methods were more effective at increasing the concentrations of the elements in plant parts. The 3 elements have been shown to have good residual values for crop production in the region. Therefore, we recommend that experiments should not be performed in existing no-till paddocks until the residual value of P, Cu and Zn applied in the old cropping system has become negligible, which could, for Cu and Zn in particular, take many years. In the second year, the experiments were used to compare 4 different ways of collecting soil samples from the top 10 cm of soil (standard soil sampling depth used in south-western Australia) to measure soil test P (Colwell), Cu (ammonium oxalate) and Zn (DTPA). The samples were either collected randomly within the plots (present method), always in the rows used to sow seed and apply fertiliser, always between the rows, or half in and half between the rows. Soil test values for P, Cu and Zn were unaffected by amount of element applied and method of application when samples were collected between rows, at random, or from all banded treatments where fertiliser was placed below the 0–10 cm sampling depth. Soil test values for samples collected in rows increased as the amount of fertiliser applied increased and were about double the values for samples collected half in and half between rows.
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Scott, B. J., D. J. Carpenter, B. D. Braysher, B. R. Cullis i C. M. Evans. "Phosphorus fertiliser placement for lupins in southern New South Wales". Australian Journal of Experimental Agriculture 43, nr 1 (2003): 79. http://dx.doi.org/10.1071/ea01201.
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Research in Western Australia and South Australia indicated that fertiliser phosphorus (P) banded below the seed of narrow leaf lupin (Lupinus angustifolius L.) at sowing was a more effective method of applying P�fertiliser than the usual placement of P with the seed. This technology has not been investigated in southern New South Wales where lupins have been known to be unresponsive to fertiliser P.We conducted 4 field experiments to examine the effect on lupin yield of applying 6 rates of P (0, 5, 10, 15, 20 and 40 kg/ha) either by placement with or below the seed. To further test responsiveness to P, an additional set of treatments was used; applying P at 40 kg/ha before sowing and then placing additional P below the seed at the 6�rates of application. The grain yield of lupin was increased by P application at all sites, despite the medium to high P�status of 3 of the 4 sites used in these experiments. However, the technique of banding P fertiliser below the seed depth rather than placing it in direct seed contact had only a small advantage in grain yield responsiveness to applied fertiliser P (P = 0.09). Fitted response curves indicated that when P was applied at 15 kg/ha, grain yield increased by 60 kg/ha at one site and 30 kg/ha at the other 3 sites, if P was deep-placed rather than applied in seed contact. This advantage of deep placement of P fertiliser was much smaller than has been reported in Western Australia.Placement of P below the seed of lupin when sown on the red earth and red-brown earth soils of southern New South Wales slightly enhanced the availability of fertiliser P. This applied even when sowing was quite shallow (2–3�cm), provided recommended rates of P fertiliser were used at conventional row spacing (17 cm). Separation of seed and fertiliser to avoid reduced germination may be an advantage when using double row spacing and higher P�application rates.
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Gaudin, Rémi. "The kinetics of ammonia disappearance from deep-placed urea supergranules (USG) in transplanted rice: the effects of split USG application and PK fertiliser". Paddy and Water Environment 10, nr 1 (11.01.2011): 1–5. http://dx.doi.org/10.1007/s10333-011-0249-3.
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Blackshaw, R. E., G. Semach, X. Li, J. T. O'Donovan i K. N. Harker. "Tillage, fertiliser and glyphosate timing effects on foxtail barley (Hordeum jubatum) management in wheat". Canadian Journal of Plant Science 80, nr 3 (1.07.2000): 655–60. http://dx.doi.org/10.4141/p99-132.
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Foxtail barley (Hordeum jubatum L.) is becoming a more severe weed problem as conservation tillage becomes widely adopted on the southern Canadian prairies. A 5-yr field study was conducted to determine the combined effects of tillage, N rate, N placement and application timing of glyphosate to manage foxtail barley in spring wheat. Wide-blade tillage conducted in fall and spring, compared to zero-till, reduced foxtail barley biomass and seed production in all yr and increased wheat yield in 4 of 5 yr. Foxtail barley was highly competitive with wheat for added N. N fertiliser placed mid-row in 10-cm-deep bands reduced foxtail barley growth in 2 of 5 yr and increased wheat yield in 3 of 5 yr compared with soil surface broadcast N. Wheat yield sometimes was similar when N was banded at 60 kg ha−1 or broadcast at 120 kg ha−1, indicating the large advantage of banding N in some situations. Glyphosate at 800 g ha−1 applied preharvest or postharvest gave similar levels of foxtail barley control in 2 of 3 yr. Results indicate that foxtail barley can be adequately managed in wheat production systems utilizing conservation tillage. Key words: Foxtail barley, Hordeum jubatum, glyphosate, integrated weed management, nitrogen placement, zero tillage
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Radford, BJ, WM Strong i GB Wilderminth. "Effects of urea and flutriafol on germination, coleptile length and establishment of wheat and barley". Australian Journal of Experimental Agriculture 29, nr 4 (1989): 551. http://dx.doi.org/10.1071/ea9890551.
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Laboratory and field experiments were conducted to determine the effects of urea fertiliser placed with the seed and flutriafol fungicide seed dressing on germination, coleoptile length and establishment of wheat (cvv. Bass and Hartog) and barley (cv. Grimmett). Interactions with depth of sowing and press wheel pressure were also measured in the field. Placement of urea (1 and 2 g/m) with the seed reduced germination, final coleoptile length and field establishment at 2 seeding depths (40 and 75 mm) and delayed field emergence. Flutriafol (0.025 or 0.1 g/kg seed) had no effect on laboratory germination or field establishment but reduced final coleoptile length in the laboratory and delayed field emergence by up to 4.3 days. Compacting the soil over the seed by applying pressure with a press wheel increased establishment from 28 to 37%. With deep sowing (75 mm), barley gave better establishment than wheat, probably because barley (cv. Grimmett) had longer coleoptiles than wheat (cv. Hartog). The effects of urea, sowing depth, press wheel pressure and crop species on establishment were generally additive. As a result, establishment varied from 3 to 80%, depending on the combination of these factors used. Our results indicate that certain combinations of current farming practices such as placement of urea with the seed, deep sowing and the use of flutriafol could cause establishment problems in winter cereals.
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Singh, R. K., R. De i B. B. Turkhede. "Effect of fertilizer placement and row arrangements on the yield of two varieties of wheat grown under dryland conditions". Journal of Agricultural Science 107, nr 1 (sierpień 1986): 113–18. http://dx.doi.org/10.1017/s0021859600066855.
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SUMMARYExperiments made under dryland conditions in the post-monsoon period for 3 years showed that deep placement of N and P fertilizers at 12 or 18 cm led to better utilization than their shallow placement at 6 cm. Grain yield was maximal when the fertilizer was placed at 18 cm depth. The yield increase by deep fertilizer placement resulted from higher tiller survival till harvest. In these treatments water use efficiency and mineralizable N content in soil were higher.Of the two varieties tested the taller cultivar (C 306) yielded more in normal years but lodging due to a severe storm in one of the years reduced its yield considerably. While the yield of the tall variety was not much affected by variations in row distances, the dwarf (DL 153–2) responded to these variations and greatest yield was obtained at a row distance of 27·5 cm.
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Chaitep, W., RDB Lefroy i GJ Blair. "Effect of placement and source of sulfur in flooded and non-flooded rice cropping systems". Australian Journal of Agricultural Research 45, nr 7 (1994): 1547. http://dx.doi.org/10.1071/ar9941547.
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Many rice-growing areas in developing countries are becoming S deficient. A glasshouse experiment was conducted to study the effect of water regimes in successive crops (nonflooded : non-flooded, flooded : flooded and flooded : non-flooded), surface (S) and deep (D) placement of sulfur fertilizer and S sources (elemental S (E) and sulfate S (S)) on the growth of rice. A soil of granitic origin was used and 35S-labelled sulfur fertilizers were used to investigate S uptake by plants and the dynamics of S in soils. Among the sulfur sources, surface-applied gypsum produced the highest total yield, which was 83.6 g pot-1 under flooded conditions. Total yields under flooded conditions were ranked in order SS > SE > DS > DE > control. In the first crop, the highest 35S recovery in the plant was 67.8% from the non-flooded SE, compared with 51.7% in the DE treatment. Deep-placed elemental S (DE) became more effective than SS and SE for the subsequent rice crop, both in terms of plant dry-matter yield and fertilizer 35S content. The highest 35S recovery in the second crop was 29.5% in the previous DE treatment in the flooded: non-flooded system. This compares with 7.5% in the SS treatment in the same cropping system.
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Kraska, Piotr, Sylwia Andruszczak, Paweł Gierasimiuk i Hubert Rusecki. "The Effect of Subsurface Placement of Mineral Fertilizer on Some Soil Properties under Reduced Tillage Soybean Cultivation". Agronomy 11, nr 5 (28.04.2021): 859. http://dx.doi.org/10.3390/agronomy11050859.
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One of the adverse effects of no-tillage is the accumulation of nutrients (in particular P and K) in the top soil layer. The subsurface application of mineral fertilizers at a depth of 10–30 cm can reduce this phenomenon and at the same time provide a relatively uniform access to soil nutrients for plant roots. Such a method of mineral fertilizer application can additionally decrease the environmental risk associated with water eutrophication because the water runoff from fields, where the soil P content is high, is reduced. The aim of this research was to evaluate the effect of the subsurface application of different rates of a compound mineral fertilizer on the content of some macronutrients, soil organic carbon content (SOC), and soil pH in a field after the harvest of soybean grown under reduced tillage conditions. The field experiment was conducted during the growing seasons of 2014/2015–2016/2017 in the village of Rogów, Zamość County, Poland. It was set up as a split-plot design in four replicates. The first experimental factor included two methods of mineral fertilization application: fertilizer broadcast over the soil surface (S); fertilizer applied deep (subsurface placed) using a specially designed cultivator (Sub-S). The other factor was the rates of the mineral fertilizer (NPKS): 85 kg∙ha−1 (F85) and 170 kg∙ha−1 (F170). Over the successive years of the study, the SOC content was found to increase. However, neither the fertilization rate nor the method of fertilizer application caused any significant difference in organic carbon. Under subsurface fertilizer application conditions, a higher soil pH was found in treatment F85, however, when the fertilizer was surface-applied, the soil in treatment F170 had a higher pH value. During the three-year study period, the P and K content in the 0–30 cm soil layer was higher than in the 30–60 cm and 60–90 cm layers. In turn, the highest Mg content was determined in the 30–60 cm layer. In the case of both mineral fertilizer application methods, a higher P content was determined in the soil fertilized at a rate of 170 kg NPKS, compared with a rate of 85 kg∙ha−1. The surface application of the higher rate of mineral fertilization resulted in an increase in the soil K content. On the other hand, when the mineral fertilizer was subsurface-applied, a higher soil K was determined in the treatments with lower mineral fertilization.
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Smychenko, V. M., i M. M. Miroshnychenko. "Impact of the depth of fertilizer localization on the nutrient regime of Luvic Chernic Phaozem and yield of spring barley". Agrochemistry and Soil Science, nr 91 (sierpień 2021): 22–30. http://dx.doi.org/10.31073/acss91-03.
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The purpose of the research is to determine the impact of the depth of local application of mineral fertilizers on the nutrient content in the arable layer of soil and the yield of spring barley. The studies were carried out during 2018 - 2020 in a temporary small-plot experiment. Soil – chernozem podzolized loamy (Luvic Chernic Phaeozem). The application of N60P60K60 in the form of nitroammophoska or a mixture of ammophos, ammonium nitrate and potassium chloride was compared to a depth of 10-12 cm and 20-22 cm from the soil surface. The row spacing of barley crops was 15 cm; the fertilizer tape was placed at a distance of 4-5 cm away from the row. Mixed soil samples were taken from fertilizer tapes twice during the growing season of barley (in the first half of the growing season and after harvesting). The weather conditions were quite contrasting: in 2018 it was dry at the beginning of the growing season and during grain ripening, in 2019 was dry only during the formation of grain, and in 2020 - rather humid and relatively cool during almost the entire growing season. At the beginning of the growing season of barley in 2018, the highest content of mineral nitrogen in the soil was found with a shallow location of the fertilizers, but in 2019-2020 - in case fertilizer tapes at 20-22 cm from the surface. Location of fertilizer at a depth of 20-22 cm also provided a higher level of mobile phosphorus and potassium in the soil than applying at a depth of 10-12 cm. After the barley harvest, the highest accumulation of mineral nitrogen in the soil in 2018 was found with shallow application and in 2019-2020 - with deeper application. A tendency of more accumulation of chlorophyll in plants was observed with an increase in the depth of fertilization. Local application of fertilizers gave a reliable increase in yield in all variants of the experiment. However, the increase was twice as high when placing the fertilizer tape was at a depth of 20-22 cm as at a depth of 10-12 cm. Application of nitroammophoska to a depth of 20-22 cm was more effective than mixtures of simple and complex fertilizers. It was concluded that the hydrothermal conditions of the growing season and the depth of the location of fertilizers mutually affect the nutrient regime of the soil. The advantage of deep fertilization is more significant under insufficient moisture.
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NUTTALL, W. F., i R. G. BUTTON. "THE EFFECT OF DEEP BANDING N AND P FERTILIZER ON THE YIELD OF CANOLA (Brassica napus L.) AND SPRING WHEAT (Triticum aestivum L.)". Canadian Journal of Soil Science 70, nr 4 (1.11.1990): 629–39. http://dx.doi.org/10.4141/cjss90-066.
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This study was conducted to determine if deep banding of P fertilizer was as efficient as placing P in a band with the seed. Phosphorus fertilizer (MAP) was deep banded at rates of 0, 10, 20, and 30 kg of P ha−1 which was compared with equal rates applied with the seed, and with one-half seed placed, one-half deep banded. The P rates were applied onto the same plots each year in a cropping sequence of canola (Brassica napus L.), four crops of wheat (Triticum aestivum L.) and then canola. Plots were located on a Melfort silty clay soil (Orthic Black Chernozem). In combination with MAP treatments, ammonium nitrate was applied by deep banding and by broadcast-incorporation to bring the total N application rate to 75 kg ha−1. Control treatments of 0–0 and 11–20 kg of N-P, respectively, were also included. In the first year of the experiment, when soil moisture conditions were dry, seed placement of the P fertilizer, on average, resulted in a significantly higher grain yield (1.01 t ha−1) of canola than deep banding (0.88 t ha−1). In the last year of the experiment, canola grain yields for the two placements were not significantly different (1.87 vs. 1.83 t ha−1). Over the 4 yr that wheat was grown there was no significant difference in grain yield between seed placed P and deep banding (2.97 vs. 2.95 t ha−1). Seed placement of P resulted in a higher grain yield (3.05 t ha−1) with N broadcast than with N deep banded (2.90 t ha−1), but with half-seed plus half-deep-banded P the yield was higher with N deep banded (3.08 t ha−1) than with broadcast-incorporated (2.87 t ha−1). The application of N and P over the 6 yr increased the available P in the soil from 7.5 (control) to 12.9 μg of P g−1 soil (N P treatments with 75 kg N ha−1). In general the application of P fertilizer either by deep banding or placement with the seed of the crop gave similar yields with the exception that at the low rates of P, seed placement was better for canola in the first year of the crop sequence. Key words: Deep banding, N, P, canola, wheat, placement
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Santos, Wedisson Oliveira, Priscila Maria de Aquino, Rafael Lucas Coca Cuesta, Isabela Maísa Honorato Saldanha, Edson Marcio Mattiello i Leonardus Vergütz. "Zinc Diffusion and Availability Affected by Different Sources in Soils of Contrasting Textures". Journal of Agricultural Science 11, nr 5 (15.04.2019): 259. http://dx.doi.org/10.5539/jas.v11n5p259.
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Trends in new fertilizer technologies should balance the nutrient release rate from fertilizers with plant demands over time, while developing suitable physical characteristics of the fertilizer’s particles. The objective of this study was to evaluate the performance of three zinc fertilizers [ZnO, ZnSO4, and a commercial co-granulated ZnO+S0 fertilizer (ES_Zn)] on Zn diffusion in soil and their agronomic performances. A Petri dish trial was carried out in order to evaluate the diffusion of Zn in the soil. The experiment was designed as a factorial scheme (3 + 1) × 2 × 3, with three Zn sources, one control treatment (without Zn application), two soils of contrasting textures (sandy and clay), and three incubation times (1, 30 and 60 d). The experiment was carried out under a completely randomized design with four replications. Zinc diffusion was assessed according to the method proposed by Degryse et al. (2015) along of incubation times. For that, a ZnSO4 solution or ZnO suspension was applied by pipetting 15 μL of solution or suspension into a small hole (~0.5-cm deep) in the center of the Petri dish. A single pastille of ES_Zn fertilizer (30±0.5 mg) was placed in the center of the Petri dish, at the same depth. Soil was watered to 80% of field capacity. Filter papers (Whatman) were impregnated with CaCO3 and placed on the soil surface. After 2 h of reaction, the CaCO3-impregnated filter papers were collected, and the precipitated Zn in the papers was colored with dithizone, giving a pink color. The performance of Zn sources was evaluated in a greenhouse through a successive maize-soybean-millet crop. The trial was designed as a 2 × (3 × 3 +1) factorial scheme, being two soils (sandy and clay), three Zn sources (ZnSO4, ZnO, and ES_Zn), three Zn doses (1.5, 3.0, and 6.0 mg dm-3 Zn), and a control treatment. The experiment was a randomized block design with four replications, being the experimental unit composed of a pot with 4 dm3 of soil. Pastille ES_Zn, ZnO (as suspension), and ZnSO4 (as solution) were applied at five equidistant points, at 5 cm below the soil surface. After 30, 60 and 60 days of planting, shoot of maize soybean and millet were harvest, oven-dried at 70 °C for 72 h (until constant weight), weighed and milled for chemical analysis. ES_Zn fertilizer promoted a delay Zn release in the soil, being effective as a fertilizer only in the last crop (millet), as well as ZnO. Zinc oxide and ZnSO4 had similar performances for increasing Zn availability in the inner soil portion, but its diffusion in soil was superior when the source was sulfate. The highly soluble ZnSO4 was more effective than ZnO-based fertilizers in terms of plant nutrition, especially for the two first crops. Our results also suggest that ZnO is solubilized in soil at high pH (6.6), its dispersion in soil being a key factor for the dissolution rate.
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Kargbo, M. B., Shenggang Pan, Zhaowen Mo, Zaiman Wang, Xiwen Luo, Hua Tian, Md Faruque Hossain, Umair Ashraf i Xiangru Tang. "Physiological Basis of Improved Performance of Super Rice (Oryza sativa) to Deep Placed Fertilizer with Precision Hill-drilling Machine". International Journal of Agriculture and Biology 18, nr 04 (1.07.2016): 797–804. http://dx.doi.org/10.17957/ijab/15.0173.
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Medina, L. Carolina, Thomas A. Obreza, Jerry B. Sartain i Robert E. Rouse. "Nitrogen Release Patterns of a Mixed Controlled-release Fertilizer and Its Components". HortTechnology 18, nr 3 (styczeń 2008): 475–80. http://dx.doi.org/10.21273/horttech.18.3.475.
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Applying water-soluble nitrogen (N) fertilizer to Florida citrus (Citrus spp.) trees on deep sandy soils may lead to poor nutrient use efficiency and possible nitrate contamination of groundwater if rainfall or irrigation is excessive. Controlled-release fertilizer (CRF) is a possible alternative to increase N uptake efficiency and minimize losses to the environment, but current grower acceptance is limited as a result of lack of experience with CRF performance and its high relative cost. The objective of this study was to measure the N release characteristics of a CRF blend (CitriBlen®) designed for mature Florida citrus trees and its three CRF components [Agrocote® Type A, Agrocote® Type C(D), and Agrocote® Poly-S®] under laboratory and field conditions. We first characterized N release from these CRF materials using a 270-day laboratory soil incubation. The quantity of N released was influenced by CRF material used; after 270 days, cumulative leached N recoveries were 90%, 82%, 85%, and 69% of the total N applied as CitriBlen®, Agrocote® Type A, Agrocote® Type C(D), and Agrocote® Poly-S®, respectively. We then measured the N release patterns of the fertilizers in a 1-year field evaluation and developed their N release curves. Studies were simultaneously conducted in central and southwestern Florida. Mesh bags containing 3.5 g of elemental N from each source were placed on the soil surface within the irrigated zone under a citrus tree canopy to estimate N release rates from the fertilizers. Despite differential N release rates between locations, at 1 year, the rank of N release was Type A > CitriBlen® > Poly-S® > Type C(D). CitriBlen® N release patterns matched well with the current University of Florida, Institute of Food and Agricultural Sciences citrus fertilization strategy recommended as a best management practice.
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SCHULZ, R., T. MAKARY, S. HUBERT, K. HARTUNG, S. GRUBER, S. DONATH, J. DÖHLER i in. "Is it necessary to split nitrogen fertilization for winter wheat? On-farm research on Luvisols in South-West Germany". Journal of Agricultural Science 153, nr 4 (1.05.2014): 575–87. http://dx.doi.org/10.1017/s0021859614000288.
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SUMMARYMineral nitrogen (N) fertilization in cereals is commonly split into three or four applications. In order to simplify N fertilization, a single N application either broadcast or placed on the soil surface was compared to conventionally split fertilization for winter wheat (Triticum aestivum L.). The 4-year experiment (2007–2010) was performed using a participatory approach on farmers’ fields on deep loamy soils (Luvisols) in South-West Germany.Grain yield and crude protein contents differed only slightly or not at all between treatments including different N fertilizer types (calcium ammonium nitrate, urea ammonium nitrate solution, urea) and application techniques (broadcast, placed). Furthermore, no differences were found for the yield components ears/m2 and thousand grain weight. Inorganic N in the soil profile after harvest was generally below 40 kg N/ha and did not differ between treatments. In the area where N was placed, mineral N was depleted during the vegetation period.At the experimental sites a single N application in the period between tillering and stem elongation was sufficient to achieve high yield and quality of winter wheat without increased risk of nitrate leaching. This finding was independent of the method of application or the type of fertilizer.
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Islam, MR, MP Akhter, A. Huda, MA Hashem i MA Asad. "Forms and Placement of Nitrogen Fertilizers Influence Nitrogen Use Efficiency and Yield of BRRI Dhan49 under Continuous Flooded Condition". Journal of Environmental Science and Natural Resources 11, nr 1-2 (30.09.2019): 53–58. http://dx.doi.org/10.3329/jesnr.v11i1-2.43366.
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An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during Aman season of 2016 to evaluate the effects of deep placement of N fertilizers in the form of USG and NPK briquettes in comparison with PU on nitrogen use efficiency and yield of BRRI dhan49. The soil was silt loam in texture having pH 6.27, organic matter content 1.95% and total N 0.136%. The experiment was laid out in a RCBD with eight treatments and three replications. The PU was applied in three equal splits. The USG and NPK briquettes were deep placed at 10 DAT and the briquettes were placed at 8-10 cm depth between four hills at alternate rows. The maximum grain yield of 5981 kg ha-1 was recorded in T3 which was statistically similar with T2 and T6. The highest straw yield of 6381 kg ha-1 was observed in T3. The lowest grain yield (3265 kg ha-1) and straw yield (4280 kg ha-1) was recorded in T3. The deep placement of USG and NPK briquettes enhanced both the recovery of applied N and N use efficiency in comparison with broadcast application of prilled urea.
J. Environ. Sci. & Natural Resources, 11(1-2): 53-58 2018
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Malhi, S. S., i K. S. Gill. "Placement, rate and source of N, seedrow opener and seeding depth effects on canola production". Canadian Journal of Plant Science 84, nr 3 (1.07.2004): 719–29. http://dx.doi.org/10.4141/p03-174.
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Seedrow-placement of N fertilizer can save money and time, but it can cause reduced emergence and yield. From 1998 to 2000, a field experiment was conducted on a silty clay loam (Black Chernozem) soil at Melfort, Saskatchewan. The objectives were to determine the influence of placement, rate and source of N, seedrow opener and seeding depth on the emergence, yield, N uptake, and seed protein and oil content of canola (Brassica napus L. ‘Quest’). The treatments were optimum (1.5 cm) and deep (4.5 cm) seeding depths in two main plots with 17 subplots of different combinations of N sources [urea and ammonium nitrate (AN)], rates (0, 40, 80 and 120 kg N ha-1) and placements (sideband and seedrow) using two seedrow openers (knives – 2 cm spread, and shovels – 20 cm spread). Sidebanding of 40, 80 and 120 kg N ha-1 and seedrow placement of 40 kg N ha-1 increased yield, N uptake and seed protein content, had no detrimental effect on emergence, and reduced seed oil content. Compared to sidebanding, seedrow placement of 80 and 120 kg N ha-1 generally reduced emergence, yield and N uptake, with relatively severe effect at higher N rate, but had no effect on seed protein and oil content. The yield and N uptake of canola responded up to 120 kg N ha-1 with sidebanding compared to 40 kg N ha-1 for yield and 80 kg N ha-1 for N uptake with seedrow placement. Deep seeding reduced emergence, yield and N uptake in many cases, had no effect on seed protein content and reduced oil content in some treatments. At low rates of N, emergence was generally better with knives, while shovels tended to be superior at higher rates of seedrow-placed N. In general, the negative impact of seedrow placement compared to sideband placement of N was more severe with deeper seeding, higher N rate and narrower width of seedrow placement band. In summary, the findings indicated that practices that placed seed and fertilizer in a way that maximized canola emergence and minimized seedling damage from fertilizer, consistently optimized seed yield response to N fertilizer. Key words: Canola, N placement, N rate, N source, seeding depth, seedrow opener
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Broschat, Timothy K. "Rates of Ammonium-nitrogen, Nitrate-nitrogen, Phosphorus, and Potassium from Two Controlled-release Fertilizers under Different Substrate Environments". HortTechnology 15, nr 2 (styczeń 2005): 332–35. http://dx.doi.org/10.21273/horttech.15.2.0332.
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Five-gram (0.18 oz) samples of two controlled-release fertilizers (CRFs), Osmocote 15N–3.9P–10K (8–9 month) (OSM) and Nutricote 18N–2.6P–6.7K (type 180) (NUTR), were sealed into polypropylene mesh packets that were placed on the surface of a 5 pine bark: 4 sedge peat: 1 sand (by volume) potting substrate (PS), buried 10 cm (3.9 inches) deep below the surface of PS, buried 10 cm below the surface of saturated silica sand (SS), or in a container of deionized water only. Containers with PS received 120 mL (4.1 floz) of deionized water three times per week, but the containers with SS or water only had no drainage and were sealed to prevent evaporation. Samples were removed after 2, 5, or 7 months of incubation at 23 °C (73.4 °F) and fertilizer prills were crushed, extracted with water, and analyzed for ammonium-nitrogen (NH4-N), nitrate-nitrogen (NO3-N), phosphorus (P), and potassium (K). Release rates of NO3-N were slightly faster than those of NH4-N and both N ions were released from both products much more rapidly than P or K. After 7 months, OSM prills retained only 8% of their NO3-N, 11% of their NH4-N, 25% of their K, and 46% of their P when averaged across all treatments. Nutricote prills retained 21% of their NO3-N, 28% of their NH4-N, 51% of their K, and 65% of their P. Release of all nutrients from both fertilizers was slowest when applied to the surface of PS, while both products released most rapidly in water only. Release rates in water only exceeded those in SS, presumably due to lower rates of mass flow in SS.
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Blackshaw, Robert E., Louis J. Molnar i H. Henry Janzen. "Nitrogen fertilizer timing and application method affect weed growth and competition with spring wheat". Weed Science 52, nr 4 (sierpień 2004): 614–22. http://dx.doi.org/10.1614/ws-03-104r.
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Managing crop fertilization may be an important component of integrated weed management systems that protect crop yield and reduce weed populations over time. A field study was conducted to determine the effects of various timings and application methods of nitrogen (N) fertilizer on weed growth and spring wheat yield. Nitrogen fertilizer was applied the previous fall (October) or at planting (May) at a dose of 50 kg ha−1. Nitrogen application treatments consisted of granular ammonium nitrate applied broadcast on the soil surface, banded 10 cm deep between every crop row, banded 10 cm deep between every second crop row, or point-injected liquid ammonium nitrate placed between every second crop row at 20-cm intervals and 10 cm deep. Treatments were applied in 4 consecutive yr to determine annual and cumulative effects over years. Density and biomass of wild oat, green foxtail, wild mustard, and common lambsquarters were sometimes lower with spring- than with fall-applied N. Spring wheat yield was never lower and was higher in 50% of the cases, when N was spring rather than fall applied. Nitrogen application method generally had larger and more consistent effects than application timing on weed growth and wheat yield. Shoot N concentration and biomass of weeds were often lower with subsurface banded or point-injected N than with surface broadcast N, and concurrent increases in spring wheat yield usually occurred with these N placement treatments. Depending on the weed species, the weed seedbank at the conclusion of the 4-yr study was reduced by 25 to 63% with point-injected compared with broadcast N. Information gained in this study will contribute to the development of more integrated and cost-effective weed management programs in wheat.
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Karamanos, R. E., J. T. Harapiak i N. A. Flore. "Long-term effect of placement of fertilizer nitrogen and phosphorus on barley yields". Canadian Journal of Plant Science 88, nr 2 (1.04.2008): 285–90. http://dx.doi.org/10.4141/cjps07138.
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An experiment that was established in 1990 to assess depth and method of placement of nitrogen (N) and phosphorus (P) fertilizer on the yield of continuous barley (with 1 yr interruption with canola in 1995) was continued to 2001. Annually, 80 kg N ha-1 were banded either at 7.5 to 10 or 15 to 17.5 cm depth alone or in combination with 40 kg P2O5 ha-1; the latter was either seedrow placed or banded with the N (dual banding), or split 1/2 in the seedrow and 1/2 in the band. An unfertilized control was maintained in all years. Temperature after seeding had a marked effect on the effectiveness of depth of N and P placement as well as the method of P placement. Shallow (7.5 to 10 cm depth) placement resulted in greater yields in 8 of the 11 yr that barley was grown and was never inferior to deeper placement (15 to 17.5 cm); this advantage was directly related to cooler-than-normal temperature after seeding. Cooler-than-normal temperatures also resulted in benefits from seedrow placed P; however, benefits were not as frequent as those obtained by either dual banding or splitting P between seedrow and the band. It would appear that overall benefits from banding P together with N (dual band), independently of the depth of banding, are greater than those from seedrow placing, as those benefits from the latter are less frequent and of considerably less magnitude. Key words: Band, dual band, seedrow, shallow, deep
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Alam, Md, Richard Bell, Nazmus Salahin, Shahab Pathan, A. T. M. A. I. Mondol, M. J. Alam, M. H. Rashid, P. L. C. Paul, M. I. Hossain i N. C. Shil. "Banding of Fertilizer Improves Phosphorus Acquisition and Yield of Zero Tillage Maize by Concentrating Phosphorus in Surface Soil". Sustainability 10, nr 9 (10.09.2018): 3234. http://dx.doi.org/10.3390/su10093234.
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Zero tillage increases stratification of immobile nutrients such as P. However, it is unclear whether near-surface stratification of soil P eases or hampers P uptake by maize (Zea mays L.) which needs an optimum P supply at/before six–leaf–stage to achieve potential grain yield. The aim of the three-year study was to determine whether P stratification, under zero tillage, impaired yield of maize and which P placement methods could improve P uptake on an Aeric Albaquept soil subgroup. Phosphorus fertilizer was placed by: (a) broadcasting before final tillage and sowing of seeds; (b) surface banding beside the row; and (c) deep banding beside the row (both the band placements were done at three–four leaf stage) Phosphorus treatments were repeated for 3 years along with three tillage practices viz.: (a) zero tillage (ZT); (b) conventional tillage (12 cm; CT); and (c) deep tillage (25 cm; DT). In the third year, all the tillage practices gave similar yield of Bangladesh Agricultural Research Institute (BARI) hybrid maize–5, but the highest grain yield was obtained by surface band P placement. After three years of tillage and P placements, the root mass density (RMD) at 0–6 cm depth increased significantly from 1.40 mg cm−3 in DT under deep band placement to 1.98 mg cm−3 in ZT under surface band placement, but not at the other depths. The combination of ZT practices, with broadcast or surface band placement methods, produced the highest available, and total P, content in soil at 0–6 cm depth after harvesting of maize. Accordingly, a significant increase in P uptake by maize was also found with surface banding of P alone and also in combination with ZT. Organic carbon, and total N, also increased significantly at depths of 0–6 cm after three years in ZT treatments with P placed in bands. By contrast, CT and DT practices, under all placement methods, resulted in an even distribution of P up to 24 cm depth. Phosphorus application, by surface banding at the three–four leaf stage, led to increased P uptake at early growth and silking stages, which resulted in highest yield regardless of tillage type through increased extractable P in the soil. Even though ZT increased P stratification near the soil surface, and it increased plant available water content (PAWC) and RMD in the 0–6 cm depth, as did surface banding, it did not improve maize grain yield. Further research is needed to understanding the contrasting maize grain yield responses to P stratification.
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WIDMER, CHAD L. "The hydroid and early medusa stages of the deep sea jellyfish Earleria purpurea (Hydrozoa: Mitrocomidae) from the Monterey Bay Submarine Canyon, USA". Zootaxa 2902, nr 1 (1.06.2011): 59. http://dx.doi.org/10.11646/zootaxa.2902.1.3.
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The hydroid and early medusa stages of the deep sea hydrozoan jellyfish Earleria purpurea (Hydrozoa: Mitrocomidae) are described. Mature medusae were collected from the Monterey Bay submarine canyon near Monterey, California, USA utilizing a remotely operated vehicle and returned to the laboratory for culturing. In vitro fertilized eggs developed into free-swimming planulae larvae that settled and metamorphosed into benthic hydroid colonies consisting of feeding hydranths and medusa producing gonangia. Newly released medusae were grown to maturity and placed on educational display at the Monterey Bay Aquarium. The hydranths and gonangia were compared and found to be distinct from those of E. corachloeae the only other member of the Genus Earleria with a described life cycle.
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Islam, Md Rafiqul, Snigdha Khatun, Azmul Huda, M. Mazibur Rahman i Mahbubul Alam Asad. "Nitrogen use efficiency and yield of BRRI dhan49 as influenced by different forms of N fertilizers under AWD condition". Research in Agriculture Livestock and Fisheries 6, nr 1 (13.05.2019): 27–33. http://dx.doi.org/10.3329/ralf.v6i1.41383.
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An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during Aman season of 2016 to evaluate the effects of deep placement of N fertilizers in the form of urea super granule (USG) and NPK briquettes in comparison with prilled urea (PU) on nitrogen use efficiency and yield of BRRI dhan49. The soil was silt loam in texture having pH 6.27, organic matter content 1.95% and total N 0.136%. The experiment was laid out in a Randomized Complete Block Design (RCBD) with eight treatments and three replications. The treatments include T1 (Control), T2 (PU, 104 kg N ha-1), T3 (USG, 104 kg N ha- 1), T4 (USG 78 kg N ha-1), T5 (USG, 52 kg N ha-1), T6 (NPK briquettes, 104 kg N ha-1), T7 (NPK briquettes, 78 kg N ha-1) and T8 (NPK briquettes, 52 kg N ha-1). All the treatments except T6, T7 and T8 received 16 kg P and 42 kg K ha-1 from TSP and MoP, respectively. In T6, T7 and T8 treatments, P and K were supplied from NPK briquettes. The PU was applied in three equal splits. The USG and NPK briquettes were deep placed 10 DAT and the briquettes were placed at 8-10 cm depth between four hills at alternate rows. Application of PU, USG and NPK briquette under alternate wetting and drying (AWD) condition exerted significant influence on yield attributes as well as grain and straw yields of BRRI dhan49. The maximum grain yield of 6311 kg ha-1 (100% increases over control) and straw yield of 6956 kg ha-1 was recorded in T3 (USG, 104 kg N ha-1). The second highest grain yield of 5865 kg ha-1 produced by T2 (PU, 104 kg N ha-1) was statistically similar with T4 (USG 78 kg N ha-1) and T6 (NPK briquettes, 104 kg N ha-1). The lowest grain yield (3155 kg ha-1) and straw yield (3908 kg ha-1) were recorded in T1 (Control). The deep placement of USG and NPK briquettes enhanced both the recovery of applied N and N use efficiency in comparison with broadcast application of prilled urea. The T5 (USG, 52 kg N ha-1) showed maximum apparent N recovery, and N use efficiency. Next to T5, the T4 depicted the position in respect of N recovery and N use efficiency. So the application of 78 kg N ha-1 in the form of USG can be recommended for the production of BRRI dhan49.
Res. Agric., Livest. Fish.6(1): 27-33, April 2019
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Davis, Amanda J., i Bernadine C. Strik. "Long-term Organic Production Systems in Northern Highbush Blueberry: Placing Weed Mat over Existing Organic Mulches and Changing to Nitrogen-only Fertilizer Sources Increased Yield". HortScience 56, nr 8 (sierpień 2021): 897–908. http://dx.doi.org/10.21273/hortsci15908-21.
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In long-lived organic blueberry production systems, nutrient imbalances caused by some fertilization and mulching practices can reduce plant growth and yield. The ability to balance nutrient levels and thus improve productivity over time was evaluated in a mature planting of ‘Duke’ and ‘Liberty’ that had been used to study different mulching practices [sawdust (9-cm deep), yard-debris compost (4-cm) topped with sawdust (5-cm), and weed mat] and various rates and sources of N fertilizer (feather meal or fish solubles, each applied initially at “low” or “high” rates of 29 and 57 kg·ha−1 N in 2007–08 and then increased incrementally as the planting matured to 73 and 140 kg·ha−1 N in 2013–16). In Winter 2016–17, existing weed mat was removed and replaced where it was present, and new weed mat was installed on top of any existing organic mulches, thus changing the mulch treatments to weed mat (over bare soil), weed mat over sawdust, and weed mat over compost + sawdust from 2017 to 2020. A hydrolyzed soy-protein–based fertilizer containing essentially only N was applied at a moderate rate (106 kg·ha−1 N) relative to prior treatments. Plants grown on flat and raised beds were evaluated separately. From 2016 to 2020, yield of ‘Duke’ and ‘Liberty’ increased by an average of 19% and 56%, respectively, on flat beds and 8% and 42%, respectively, on raised beds. On flat or raised beds, plants that had weed mat placed over the existing sawdust or compost + sawdust mulch had a greater increase in yield (averaging 41%) than those with weed mat alone (over bare soil; averaging 12%). Soil under weed mat alone continued to have the lowest organic matter content (averaging 3%) throughout the study. Prior fertilization source and rate had no impact on the increase in yield of ‘Duke’, whereas ‘Liberty’ plants previously fertilized with feather meal had a larger increase in yield through 2020 than those fertilized with fish solubles. Fertilizing with an intermediate rate of N from 2017 to 2020 increased yield regardless of whether plants received the low or high N rate from 2007 to 2016, confirming our previous conclusion that the low rate provided sufficient N. Soil K and leaf %K declined after discontinuing fertilization with fish solubles and use of yard-debris compost, likely a factor in yield improvement. However, there were still negative correlations between yield and leaf %K in multiple years. This study illustrated that changing mulch and fertility practices in established organic blueberry to mitigate prior applications of high K can improve plant performance, nutrient imbalances, and yield within a relatively short period of time.
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Roberts, Bruce R., Henry F. Decker, Kenneth J. Bagstad i Kathleen A. Peterson. "Biosolid Residues as Soilless Media for Growing Wildflower Sod". HortTechnology 11, nr 2 (styczeń 2001): 194–99. http://dx.doi.org/10.21273/horttech.11.2.194.
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Two biosolid-containing waste media [sewage sludge compost and incinerated biosolids (flume sand)] were tested individually, together, and in combination with a commercial growing medium for growing wildflower sod in greenhouse trials over a 3-year period. A medium composed of flume sand and Metromix (7:3 weight/weight) in 7.5 {XtimesX} 10.5 {XtimesX} 2-inch deep (19 {XtimesX} 27 {XtimesX} 5-cm) plastic trays seeded at 20 oz/1000ft2 (6.1 g·m-2) with cosmos (Cosmos bipinnatus), cornflower (Centaurea cyannis), plains coreopsis (Coreopsis tinctoria), white yarrow (Achillea millefolium) and purple coneflower (Echinacea purpurea) produced a suitable wildflower sod in 10 to 12 weeks. A single application of slow release fertilizer (Osmocote 14-14-14, 14N-4.2P-11.6K) applied as a top dressing had no significant effect on sod development; however, a 4-mil [0.004-inch (0.10-mm)] polyethylene barrier placed in the base of each container resulted in increased dry weight accumulation and a higher root to shoot ratio relative to sod grown without plastic.
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Hasan, Samia Lutfa, Md Rafiqul Islam, Mahmud Hossain Sumon i Azmul Huda. "Deep placement of N fertilizers influences N use efficiency and yield of BRRI dhan29 under flooded condition". Asian Journal of Medical and Biological Research 2, nr 2 (9.08.2016): 279–84. http://dx.doi.org/10.3329/ajmbr.v2i2.29072.
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An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during boro season of 2014 to evaluate the effect of deep placement of nitrogen (N) fertilizers on N use efficiency and yield of BRRI dhan29 under flooded condition. The soil was silt loam in texture having pH 6.27, organic matter content 1.95%, total N 0.136%, available P 3.16 ppm, exchangeable K 0.095 me%, available S 10.5 ppm and EC 348 ?S cm-1. The experiment was laid out in a Randomized Complete Block Design (RCBD) with eight treatments and three replications. The treatments were T1 [Control], T2 [Prilled urea (130 kg N ha-1)], T3 [USG, 130 kg N ha-1], T4 [USG, 104 kg N ha-1], T5 [USG, 78 kg N ha-1], T6 [NPK briquette, 129 kg N ha-1], T7 [NPK briquette, 102 kg N ha-1] and T8 [NPK briquette, 78 kg N ha-1]. All the treatments except T6, T7 and T8 received 25 kg P and 64 kg K ha-1 as TSP and MoP respectively. In T6, T7 and T8 treatments, P and K were supplied from NPK briquettes. Prilled urea was applied in three equal splits. USG and NPK briquettes were applied at 10 DAT and were placed at 8-10 cm depth within four hills at alternate row. After deep placement of USG and NPK briquette, and each split application of PU, the water samples were collected for 5 consecutive days and analyzed for NH4-N concentration in surface water. After application of N fertilizers, the NH4-N in floodwater reached peak on the 2nd day in PU treated plots and then decreased rapidly over time. In the USG and NPK briquette treated plots, the NH4-N was generated slowly but spontaneously over the entire growth period as compared to PU indicating a beneficial role of USG and NPK briquette. The highest grain yield of 7.16 t ha-1 was recorded for T6 [NPK briquette, 129 kg N ha-1] which was statistically similar to that of T3 [USG, 130 kg N ha-1] and T4 [USG, 104 kg N ha-1]. The highest straw yield of 8.05 t ha-1 was obtained for T3 [USG, 130 kg N ha-1]. The deep placement of USG and NPK briquettes enhanced the recovery of applied N and N use efficiency in comparison with the broadcast application of N fertilizers.Asian J. Med. Biol. Res. June 2016, 2(2): 279-284
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Islam, Md Rafiqul, Mahthir Been Mohammad, Mst Tazmin Akhter, Md Moyeed Hasan Talukder i Kawsar Hossen. "Effect of deep placement of N fertilizers on nitrogen use efficiency and yield of BRRI dhan29 under flooded condition". Asian Journal of Medical and Biological Research 3, nr 4 (30.01.2018): 454–61. http://dx.doi.org/10.3329/ajmbr.v3i4.35336.
Pełny tekst źródłaStreszczenie:
An experiment was conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during boro season of 2016 to evaluate the effect of deep placement of nitrogen (N) fertilizers on N use efficiency and yield of BRRI dhan29 under continuous flooded condition. The soil was silt loam in texture having pH 6.27, organic matter content 1.95%, total N 0.136%, available P 3.16 ppm, exchangeable K 0.095 me%, available S 10.5 ppm and EC 348 μS cm-1. The experiment was laid out in a Randomized Complete Block Design (RCBD) with eight treatments and three replications. The treatments were T1 [Control], T2 [Prilled Urea, 130 kg N ha-1] , T3 [USG, 130 kg N ha-1], T4 [USG, 104 kg N ha-1], T5 [USG, 78 kg N ha-1], T6 [NPK briquette , 129 kg N ha-1], T7 [NPK briquette, 102 kg N ha-1] and T8 [NPK briquette, 78 kg N ha-1]. All the treatments except T6, T7 and T8 received 25 kg P and 64 kg K ha-1 as TSP and MoP, respectively. In T6, T7 and T8 treatments, P and K were supplied from NPK briquettes. Prilled urea was applied in three equal splits. USG and NPK briquettes were applied at 10 DAT and were placed at 8-10 cm depth between four hills at every alternate row. The results demonstrate that all the yield components except 1000-grain weight and yields of BRRI dhan29 responded significantly to the deep placement of N in the form of USG and NPK briquettes under continuous flooded condition. The highest grain yield of 6561 kg ha-1 was recorded in T3 [USG, 130 kg N ha-1] which was statistically similar to that ofT4 [USG, 104 kg N ha-1].The highest straw yield of 6876 kg ha-1 was obtained in T3 [USG, 130 kg N ha-1]. The lowest grain yield (3094 kg ha-1) and straw yield (3364 kg ha-1) were found for T1 (Control). The deep placement of USG and NPK briquettes enhanced the recovery of applied N and N use efficiency in comparison with the broadcast application of PU. The highest value of NUE (32.05 kg grain increase per kg N applied) was obtained in T5 [USG, 78 kg N ha-1] followed by T4 [30.75 kg grain increase per kg N applied) and the lowest value was found in T8 [130 kg N ha-1 from PU]. Based on yield, N use efficiency and cost-benefit analysis, an application of 104 kg N ha-1 as USG can be recommended as the best treatment for achieving satisfactory yield of boro rice (cv. BRRI dhan29) at BAU farm and at adjacent areas under AEZ 9 (Old Brahmaputra Floodplain).Asian J. Med. Biol. Res. December 2017, 3(4): 454-461
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Davenport, Joan R., i Carolyn DeMoranville. "Temperature Influences Nitrogen Release Rates in Cranberry Soils". HortScience 39, nr 1 (luty 2004): 80–83. http://dx.doi.org/10.21273/hortsci.39.1.80.
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Native nitrogen is released when soils are mineralized. The amount of N released by this process depends on the amount of organic matter present and soil temperature. Cranberry (Vaccinium macrocarpon Ait.) grows in acidic soils with a wide range in organic matter content. To evaluate release of cranberry soil N at varied soil temperatures, intact soils were collected from sites that had received no fertilizer. Soils were cored and placed in polyvinyl chloride (PVC) columns 20 cm deep × 5 cm in diameter. Four different soil types, representing the array of conditions in cranberry soil (mineral, sanded organic, organic peat, and muck) were used. Additional columns of sand soil (pH 4.5) that had been pH adjusted to high (6.5) and low (3.0) were also prepared. Each column was incubated sequentially at six different temperatures from 10 to 24 °C (2.8 °C temperature intervals) for 3 weeks at each temperature, with the soils leached twice weekly to determine the amount of N release. The total amount of N in leachate was highest in the organic soils, intermediate in the sanded organic, and lowest in the sands. At the lowest temperature (10 °C), higher amounts of N were released in sanded organic and sand than in organic soils. This was attributed to a flush of mineralization with change in the aerobic status and initial soil warming. The degree of decomposition in the organic soils was important in determining which form of N predominated in the leachate. In the more highly decomposed soil (muck), most of the N was converted to nitrate. In the pH adjusted sand, high soil pH (6.5) resulted in an increase in nitrate in the leachate but no change in ammonium when compared to non-adjusted (pH 4.5) and acidified (pH 3.0) treatments. This study suggests that for cranberry soils with organic matter content of at least 1.5% little to no soil-applied fertilizer N is needed early in the season, until soil temperatures reach 13 °C. This temperature is consistent with the beginning of active nutrient uptake by roots. Soil N release from native organic matter was fairly consistent until soil temperatures exceeded 21 °C, indicating that when temperatures exceed 21 °C, planned fertilizer applications should be reduced, particularly in highly organic soils.
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Bijay-Singh i J. C. Katyal. "Relative efficacy of some new urea-based nitrogen fertilizers for growing wetland rice on a permeable alluvial soil". Journal of Agricultural Science 109, nr 1 (sierpień 1987): 27–31. http://dx.doi.org/10.1017/s0021859600080941.
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SummaryEfficiency of N contained in some modified urea fertilizers was studied for wetland rice grown in an alkaline, low organic matter Fatehpur loamy sand (Typic Ustipsamment) soil having an average percolation rate of 109 mm/day. In the four field experiments, sulphurcoated urea (SCU) produced significantly more rice grain than urea supergranules (USG) or divided applications of urea or ammonium sulphate. Application of SCU at 58 kg N/ha yielded as much rice grain as was produced by divided application of urea at 116 kg N/ha. The N uptake data suggested that SCU-N was more efficiently translated into grain yield than urea N. Granular (7-day release rate 19%) and forestry (7-day release rate 29%) grades of SCU were equally effective. However, application of half the N basally through SCU and the remaining half top dressed as urea failed to outyield all urea divided in three applications. The indigenous coated materials, rock-phosphate-coated urea and urea gypsum, also did not perform better than divided urea applications as these did not possess a 7-day release rate less than 95%. Urea supergranules placed in the reduced zone of the soil could not come to the level of divided application of urea or ammonium sulphate. The N uptake data indicated that USG-N was correspondingly inefficiently utilized by rice. When the deep placement aspect of USG was combined with slow-release properties of SCU in the form of sulphur-coated urea supergranules (SCUSG), the performance of this product was inferior even to the divided application of urea. Undissolved or partially dissolved granules of SCUSG could be recovered even after the harvest of the crop.
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Núñez-Moreno, Humberto, James L. Walworth, Andrew P. Pond i Michael W. Kilby. "Soil Zinc Fertilization of ‘Wichita’ Pecan Trees Growing Under Alkaline Soil Conditions". HortScience 44, nr 6 (październik 2009): 1736–40. http://dx.doi.org/10.21273/hortsci.44.6.1736.
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The effect of soil banding zinc sulfate and zinc (Zn)-EDTA was evaluated over a period of 4 years on established ‘Wichita’ pecans [Carya illinoinensis (Wangenh.) K. Koch] growing in alkaline, calcareous soil. Treatments evaluated were ZnSO4 applied at 74 kg Zn/ha and Zn-EDTA at 19 kg Zn/ha. These materials were applied just once on 23 Mar. 2005. Fertilizers were injected in two bands placed 1.2 m from either side of the trunk of the tree and 18 cm deep. Treatments were replicated four times in a randomized complete block design. Data collected included foliar Zn concentrations throughout the season, midseason foliar nutrient concentrations, leaflet growth, nut yield, and nut quality. Significant differences in foliar Zn levels were found 1 month after application of Zn-EDTA. Differences also were noted during the next 3 years on ≈25% of the sampling dates. Yields of in-shell pecans averaged 2800 kg·ha−1 during the 3 years of harvest but were unaffected by treatments. Nut quality also was unaffected. Nut kernel percentage was very high, ranging from 61.2% to 63.6% during the study. Growth, measured as leaflet area and trunk cross-sectional area, was unaffected by Zn application. Chlorophyll index ranged from 47.5 to 48.0 in 2007 and from 44.7 to 45.4 in 2008 and was unaffected by applied treatments. Zn-EDTA increased Zn uptake slightly by ‘Wichita’ pecan trees in alkaline, calcareous conditions during 3 years after one soil band injection. Ongoing research on potted pecan trees (with the same soil used in the present study) suggests that Zn-EDTA can very effectively increase Zn uptake if placed in close proximity to the tree roots. Additional research is needed to refine application and placement methods in these types of soils to produce a more effective and consistent response.
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Machaty, Z., C. Wang i K. Lee. "176 CYTOCHALASIN PREVENTS SPERM HEAD INCORPORATION INTO FERTILIZED PIG OOCYTES". Reproduction, Fertility and Development 24, nr 1 (2012): 200. http://dx.doi.org/10.1071/rdv24n1ab176.
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At fertilization, an acrosome-reacted sperm fuses to the plasma membrane of the oocyte. It is then internalized into the ooplasm and its head forms the male pronucleus that moves toward the female pronucleus. Experiments using cytochalasin, an inhibitor of actin polymerization, suggest that filamentous actin is necessary for spermatozoa incorporation deep into the oocyte cytoplasm. However, the exact role of actin in the process is not entirely clear and the consequences of inhibiting actin polymerization on embryo development are not known. In the present study, we investigated the effect of cytochalasin B on fertilization and subsequent embryo development in the porcine model. In vitro-matured oocytes were rinsed in fertilization medium, a modified Tris-buffered medium supplemented with 0.1% BSA and 1 mM caffeine. Groups of 30 oocytes were placed into 50-μL droplets of the medium covered with mineral oil. Fresh semen was collected from both a wild-type boar and a transgenic boar heterozygous for the green fluorescent protein (GFP), washed 3 times in Dulbecco's PBS and added at a final concentration of 5 × 105 cells mL–1 to each droplet containing the oocytes. The gametes were co-incubated for 5 h at 39°C under 5% CO2 in air. In the treatment group, 10 μg mL–1 of cytochalasin B was supplemented into the fertilization droplets; control groups received an equivalent amount of dimethyl sulfoxide, the solvent used to dissolve the inhibitor. After gamete co-incubation, potential zygotes were transferred to PZM-3 medium for culture. In experiment 1, mature oocytes were fertilized with the wild-type boar sperm. Embryos at the 6- or 8-cell stage were then collected, the blastomeres were separated and DNA from each blastomere was isolated for PCR analysis to monitor the presence of the male-specific SRY gene. In experiment 2, the GFP transgenic sperm was used for fertilization. Fertilized oocytes were cultured for 7 days and the resultant embryos were examined for GFP expression using an epifluorescence microscope. The developmental stages of the embryos were also determined by staining their nuclei with Hoechst 33342. We found that after cytochalasin B treatment, only 19.1% (21/110) of the blastomeres were positive for the SRY gene, whereas in the control group, SRY was detected in 54.5% (61/112) of the cases. In addition, in the cytochalasin B-treated group, 1.9% (7/376) of the embryos expressed GFP, as indicated by green fluorescence; this percentage was 35.4% (146/412) in the control embryos. The frequency of 2-cell and blastocyst-stage embryos was similar between the control and cytochalasin B-treated groups (84.1 vs 81.0%; and 11.6 vs 12.5%, respectively). The results indicate that the presence of cytochalasin B during fertilization effectively blocks the incorporation of the male nucleus into the newly formed zygote without affecting the developmental potential of the pre-implantation embryo.
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Wyatt, Jim E., Don D. Howard, Don D. Tyler i Craig H. Canaday. "135 Tillage Systems and Fertilization Methods for Staked Tomatoes". HortScience 34, nr 3 (czerwiec 1999): 465A—465. http://dx.doi.org/10.21273/hortsci.34.3.465a.
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Reduced and no-tillage vegetable production is gaining in acceptance in the Southeastern United States. Conventional till, strip-till, and no-tillage systems with different methods of nitrogen application in staked tomatoes were studied in Tennessee. Conventional tillage plots were prepared by disking and harrowing, strip till plots were cultivated ≈16 cm deep with a rear-tine tiller (≈50 cm wide), and no-till plots were established in chemically killed wheat with no cultivation. Four nitrogen treatments were applied at 67.2 kg·ha-1 N using liquid KNO3. The treatments included applying the N either 1) in a 54-cm strip or 2) in a 108-cm strip over the row, 3) by banding ≈10 cm on each side of and ≈10 cm below the row, or 4) by injecting into the drip irrigation system in increments of 11.2, 22.4 and 33.6 kg·ha-1 N at 2, 4, and 6 weeks after transplanting, respectively. Tillage had little effect on tomato yield but the strip till and no-till plots allowed cultivation or spraying soon after a rainstorm. The improved trafficability was a distinct advantage over the conventionally tilled plots in the study. Total yield was significantly higher in strip tilled plots, but within fruit size categories (small, medium, large and extra large) no differences were found due to tillage system. The fertilizer treatments in which N was placed in 54- or 108-cm strips over the row produced the highest yield of early large and early extra large fruit, which are usually the most valuable portion of the crop. Banded and injected nitrogen treatments tended to produce large amounts of fruit late in the season, a period when tomato prices are generally lower.
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Poliakovskyi, V. M., V. M. Mykhalska, L. V. Shevchenko i М. S. Gruntkovskyi. "Biological features of guests and requirements for their containment". Sučasne ptahìvnictvo, nr 11-12 (23.12.2020): 22–27. http://dx.doi.org/10.31548/poultry2020.11-12.022.
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This article reveals the biological features of guinea fowl and methods of keeping them. Guinea fowl are raised and bred to produce dietary meat, high-quality eggs, and to control pests of crops: snails, insects, including the Colorado potato beetle. The main direction of growing guinea fowl is meat, in terms of meat yield guinea fowl are not inferior to chickens. The taste of guinea fowl resembles game, but it is more tender, juicy and not fibrous. Guinea fowl have a horizontally placed oval body, short neck, large head with a strong growth in the crest, short, lowered tail. Guinea fowl are unpretentious, easily acclimatized to any natural and climatic conditions. The disadvantages of this species of bird include a poorly developed hatching instinct and aggression during capture. With age, the aggression of guinea fowl increases. This bird is also known to make unpleasant shrill sounds, which is why they are sometimes refused to breed. When keeping guinea fowl, it should be borne in mind that domestic guinea fowl inherited from the wild the ability to fly well. They are mobile, timid, reluctant to go to the nest and often lay eggs in hidden, cozy places. After isolating males from the herd, females are able to lay fertilized eggs for more than 10 days. This species of birds is quite well acclimatized and shows a fairly high egg productivity in different methods of cultivation. There are several ways to keep guinea fowl. The most common walking method, which involves keeping guinea fowl during the day on pasture, and at night — indoors. Keeping on the floor (on deep litter) is used when it is not possible to give the bird exercise. The cage method allows to increase the efficiency of production area, reduce feed costs by 15%, to mechanize the care and maintenance of poultry houses.
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Way, M. O., i R. G. Wallace. "Control of Rice Water Weevil with Exp 80698A 75 Fs in a Water-Seeded, Pinpoint Flood Culture, 1997". Arthropod Management Tests 23, nr 1 (1.01.1998): 269–70. http://dx.doi.org/10.1093/amt/23.1.269a.
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Abstract The experiment was conducted at the TAMU Agricultural Research and Extension Center at Beaumont and was designed as a RCB with 6 treatments and 4 replications. Each plot was 15 ft X 8 ft and surrounded by a metal barrier to prevent movement of insecticide. On 19 Apr, plots were fertilized with urea at 113 lb nitrogen/acre and treated with Ordram 15 G at 17 lb/acre. Selected plots were sprayed with selected insecticide treatments on 19 Apr using a 4 nozzle (tip size 800067, 50 mesh screens); hand-held spray rig pressurized with CO2. Final spray volume was 16 gpa. The insecticides were incorporated into dry League soil using a rake. Immediately after incorporation, plots were flooded. On 22 Apr, plots were planted with sprouted seed at 120 lb dry seed/acre. Sprouted seeds were prepared by soaking untreated, dry seed for 24 h followed by draining and drying for 24 h. Selected plots were hand planted with selected seed treatments which were applied using the “Le Sak” method in which sprouted seed was placed in a plastic bag and insecticide poured over the seed. The seed and insecticide were mixed inside the bag until seed adsorbed all insecticide. The bag was opened and insecticide allowed to dry on seed. On 25 Apr, plots were drained and reflooded 29 Apr. Rice in most treatments emerged through water on 1 May; however, untreated rice and rice seed treated with EXP 80698A at 0.05 lb (AI)/acre did not emerge through water for 1 to 3 d later. On 10 May (9 d after emergence of rice through water), selected plots were treated with Furadan 3 G at 20 lb/acre using a hand-held shaker jar. On each of 22 May, 11 Jun, and 10 Jul, plots were fertilized with urea at 30 lb nitrogen/acre; thus, total nitrogen applied to plots during the growing season was 203 lb/acre. On each of 28 May and 10 Jun (27 and 43 d, respectively, after emergence of rice through water), five 4-inch diam X 4 inch deep soil cores (each containing at least 1 rice plant) were removed from each plot. Rice plants in cores were washed and immature RWW recovered from the roots. At maturity, plots were harvested (15 Aug = 106 to 109 d after emergence of rice through water) with a small plot combine. Yields were adjusted to 12% moisture. Insect counts were transformed using x + 0.5 and all data analyzed by 2-way ANOVA and DMRT.
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Saeki, K., D. Iwamoto, S. Taniguchi, M. Kishi i N. Kato. "166 MATURATION OF BOVINE OOCYTES IN POLY(DIMETHYLSILOXANE) MICROWELLS AND THEIR SUBSEQUENT DEVELOPMENT FOLLOWING IN VITRO FERTILIZATION". Reproduction, Fertility and Development 26, nr 1 (2014): 197. http://dx.doi.org/10.1071/rdv26n1ab166.
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During bovine oocyte maturation, a lower density of cumulus cells surrounding oocytes reduces the developmental competence of the oocytes after IVF. Adding more cumulus cells (Hashimoto et al. 1998) rescues the developmental competence of the corona-enclosed oocytes. In this study, we examined the effects of poly(dimethylsiloxane) (PDMS) microwells (MW) for bovine oocyte maturation on the developmental competence of the oocytes following IVF. In experiment 1, MW were produced by making holes on 0.5-mm-thick PDMS plates using a 0.5-mm-diameter biopsy punch. The punched plates were placed on the bottoms of culture dishes. Bovine cumulus oocytes complexes (COC) were collected from slaughterhouse ovaries. Cumulus layers were removed from COC to prepare corona-enclosed oocytes (CEO) and denuded oocytes (DO). Then, COC, CEO, or DO were individually matured in single MW for 24 h at 39°C under 5% CO2 in air with high humidity. Ten oocytes of each group were matured in 50-μL droplets of maturation medium (group culture, GC) as controls. Maturation medium was TCM-199 supplemented with 10% FCS, 0.02 AU mL–1 FSH, and 1 μg mL–1 E2. The matured oocytes were fertilized with frozen–thawed spermatozoa. The embryos were cultured in CR1aa medium for 168 h under 5% CO2, 5% O2 and 90% N2 with high humidity. In experiment 2, effects of depth of MW for maturation on subsequent development following IVF were examined. Microwells were produced by making 0.5-mm-diameter holes on 0.5- or 1.5-mm-thick PDMS plates. Then, COC or CEO were individually matured in the MW for 24 h. Matured oocytes were fertilized in vitro and cultured for 168 h. Oocytes that were matured by GC were used as controls. In experiment 1(N = 4), rates of maturation (76–100%, n = 26 to 38), normal fertilization (53–70%, n = 44 to 49), and cleavage (61–77%, n = 114 to 117) were not different among all groups (P > 0.05; Fisher's PLSD test following ANOVA). Blastocyst rates were the same (P > 0.05) for COC matured in MW (50%) and by GC (43%). The rate for CEO that matured in MW (46%) tended to be higher (P = 0.061) than the rate for CEO that matured by GC (31%), and was comparable to the rate for COC matured by GC (43%). The blastocyst rates for DO that matured in MW and by GC were low (6%). In experiment 2 (N = 3), rates of maturation (86–100%, n = 13 to 28), normal fertilization (60–78%, n = 22 to 40), and cleavage (67–73%, n = 85 to 90) were not different among all groups (P > 0.05). However, the blastocyst rate for COC that matured in 1.5-mm-deep MW (53%) was significantly higher than the rates for COC that matured in 0.5-mm-deep MW (38%) and by GC (31%; P < 0.05). The results indicate that the developmental competence of oocytes that matured individually in PDMS MW was greater than that of oocytes that matured by GC. The deeper (1.5 mm) MW were found to be more effective for oocyte maturation than shallow (0.5 mm) MW and GC. The MW might increase density of cumulus cells surrounding oocytes, and the high cell-density enhanced the developmental competence of the oocytes.
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Way, M. O., i R. G. Wallace. "Control of a Sharpshooter with Exp 80698A and Karate, 1997". Arthropod Management Tests 23, nr 1 (1.01.1998): 273. http://dx.doi.org/10.1093/amt/23.1.273.
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Abstract The experiment was conducted in a greenhouse at the TAMU Agricultural Research and Extension Center at Beaumont and was designed as a RCB with 6 treatments and 4 replications. The greenhouse was maintained at 31° C, 70% relative humidity, and 12 h light:12 h dark. Each experimental unit was a pot (6 inch diam X 6 inch deep) filled with sifted League soil. On 30 Sep, selected pots were planted with 8 untreated or EXP 80698A 75 FS-treated seeds. Seeds were treated at the rates shown in the table using the “Le Sak” method developed by Rhone-Poulenc Ag Company. On the same day, selected pots were sprayed with EXP 80698A 75 FS at the rates shown in the table using a 4 nozzle (800067 tip size, 50 mesh screens), hand-held spray rig pressurized with CO2. Final spray volume was 9.0 gpa. On the same day, pots were fertilized with urea at 51 lb nitrogen/acre. Immediately following planting, and spraying, soil in each pot was “raked” with forceps to simulate incorporation. On 5 Oct, rice emerged through soil. On 21 Oct, selected pots were treated with Karate at the rate shown in the table using the same spray rig and final spray volume as before. Immediately after spraying Karate, a plastic cylinder was placed over 2 plants in each pot. Cylinders were 3 inch in diam so that the plant density within a cylinder was equal to a seeding rate of 90 lb/acre, given 100% emergence and survival of seeds. The cylinders were ventilated with screen windows and tops. After securing the cylinders, which served as cages, each was infested on 21 (Oct 17 d after emergence of rice through soil) with 5 adult sharpshooters. Insects were collected from untreated rice using a sweep net. Two d later, cages were inspected for live and dead sharpshooters. Data were expressed as % mortality which was transformed using arcsine. Transformed data were then analyzed by 2-way ANOVA and means separated by DMRT.
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Nasir, M., K. Sumawidjaja, K. Sumawidjaja i Irzal Effendi. "Control of Natural Food with Diazinon for Growth and Survival of Marbled Goby, Oxyeleotris marmorata (Bleeker)". Jurnal Akuakultur Indonesia 3, nr 2 (1.08.2007): 19. http://dx.doi.org/10.19027/jai.3.19-24.
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<p>Dua percobaan telah dilakukan, yaitu tanpa dan dengan larva ikan. Percobaan pertama, yang menggunakan 3 konsentrasi diazinon 0. 2 dan 4 ppm dan 3 ulangan, mempelajari pertumbuhan rotifera, cladocera dan copepoda. Percobaan kedua mempunyai 2 perlakuan, yaitu diazinon 0 dan 4 ppm (yang terbaik dari percobaan pertama) serta 4 ulangan untuk mengevaluasi: 1) ketersediaan, pemanfaatan dan susunan jasad-jasad pakan, 2) pertumbuhan dan kelangsungan hidup larva, serta 3) perkembangan larva ikan. Larva yang berumur satu hari ditebar pada saat kelimpahan rotifera tertinggi di hapa dengan kepadatan 40 larva/1 atau 3.200 larva/hapa. Hapa (mesh 0,8 mm) yang berukuran 50x40x50 cm ditempatkan dalam kolam-kolam beton yang berukuran 4,25x2,00x 0,65 m. Kolam-kolam ini mula-mula dikeringkan selama 2 hari, dipupuk dengan kotoran ayam 1.000 g/m3 dan diisi air setinggi 50 cm. Keesokan harinya kolam dipupuk dengan urea dan tripel superfosfat masing-masing 20 dan 30 g/m3. Dua hari kemudian air diberi diazinon sesuai perlakuan. Hasil percobaan pertama menunjukkan bahwa diazinon meningkatkan ketersediaan rotifera. Populasi rotifera tertinggi dicapai di kolam yang mendapat diazinon 4 ppm. Percobaan kedua memberikan laju pertumbuhan harian dan kelangsungan hidup larva ikan serta ketersediaan dan pemanfaatan rotifer tertinggi pada pemberian diazinon 4 ppm.</p> <p>Kata kunci: Pakan alami, larva. <em>Oxyeleotris marmorata, </em>diazinon. kelangsungan hidup, pertumbuhan</p> <p> </p> <p>ABSTRACT</p> <p>Two experiments were conducted, without and with fish larvae. The first experiment, utilizing 3 concentrations of diazinon, i.e. 0, 2 and 4 ppm and 3 replications, evaluated the growth of rotifers, cladocerans and copepods. The second experiment had 2 treatments, i.e. 0 and 4 ppm diazinon and 4 replications evaluated: 1) the availability, utilization and composition of food organisms, 2) the growth and survival rates offish larvae, and 3) the development of larvae. One-day old larvae were stocked at times of highest rotifer concentrations in hapas at 40 larvae/1 or 3,200 larvae/hapa. Hapas (0,8 mm mesh) of 50x40x50 cm were placed in concrete ponds of 4.25x2.00x0,65 m. The ponds were dried for 2 days, fertilized with chicken manure 1.000 g/m3 and filled with water up to 50 cm deep. Next day, the ponds were fertilized with urea and triple superphosphate 20 and 30 g/m3 respectively. Two days later, the water was treated with diazinon according to treatments. The results of the first experiment showed that diazinon increased the availability of rotifers. The highest rotifer populations were obtained in ponds receiving 4 ppm diazinon. The second experiment gave highest daily growth and survival rates of fish larvae, te availability and utilization of rotifers at 4 ppm diazinon.</p> Key words: Natural foods, larvae, <em>Oxyeleotris marmorata, </em>diazinon, survival, growth.
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Kurosaka, S., N. A. Leu i K. J. McLaughlin. "51 AGGREGATION REDUCES THE VARIATION OF GENE EXPRESSION LEVELS IN BOVINE CLONES". Reproduction, Fertility and Development 18, nr 2 (2006): 134. http://dx.doi.org/10.1071/rdv18n2ab51.
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Mammalian somatic cell clones frequently exhibit abnormal gene expression that presumably results from errors in reprogramming of the transplanted genome. In the mouse, aggregation of 4-cell stage clones with each other improves reprogramming with respect to Oct-4 expression in blastocysts and an increase in term development (Boiani et al. 2003 EMBO J. 22, 5304-5312). To determine if clone-clone aggregation has a similar beneficial effect in the bovine, we aggregated 8-16 cell bovine clones with each other and profiled gene expression levels in bovine clones and clone-clone aggregates at the blastocyst stage. Clone embryos were produced from fibroblasts and cultured in vitro in SOF supplemented with fetal bovine serum at 39�C in an atmosphere of 5% CO2, 5% O2, and 90% N2. For aggregation of embryos, we first removed the zonae pepellucidae by treatment with 0.5% pronase at the 8-16 cell stage and then placed two zona-free embryos per well into deep microwells produced on the bottom of a culture dish by pressing a heated darning needle onto the surface. Seven to 10 microwells in close proximity were covered by a culture 50-�L drop of culture medium, and embryos were cultured until Day 7. Real-time RT-PCR analysis for Oct-4, DNA methyltransferase 1 (Dnmt1), Dnmt3, glucose transporter 1 (Glut1), Glut3, and Poly(A) polymerase (PolyA) was performed on reusable Dynabead Oligo (dT)25-cDNA libraries synthesized from individual blastocysts at Day 7. In vitro-fertilized embryos were used as controls. To compare the variation of gene expression in each embryo within the group, the coefficient of variation (COV; standard deviation/mean) was calculated. Although spatial distribution of Oct-4 transcript is normal in bovine blastocyst stage clones (Kurosaka et al. 2004 Reprod. Fertil. Dev. 16, 147), we detected disturbances in the level of Oct-4 expression in clones: 44.4% (8 of 18) of clones expressed Oct-4 within a range of 0.5- and 1.5-fold of the average level of expression in IVF embryos, compared to 81.8% (9 of 11) of IVF embryos. Only 22.2% (4 of 18) of clones expressed all genes examined within a range of 0.5- and 2.0-fold of the average level of IVF embryos, versus 45.5% (5 of 11) of IVF embryos. Clone-clone aggregation did not increase the proportion of clones with normal expression levels but did reduce the coefficient of variation of gene expression levels between individual clones for the genes Oct-4, Dnmt1, Dnmt3a and PolyA, but not for Glut1 and Glut3. Interestingly, bovine clone-clone aggregates (n = 25) had less variation between individual embryos compared to IVF aggregates (n = 11) for all genes except Glut1 and Glut3, although variation of single clones was larger than that of single IVF embryos. Analysis of Oct-4 and �-Actin transcripts in mouse clone blastocysts indicated a similar decrease in gene expression variation subsequent to aggregation of mouse clones. These results demonstrate that bovine pre-implantation stage clones exhibit a high degree of variation in gene expression levels and suggest that aggregation of clones is beneficial in reducing the variation in expression of some genes.
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Sharna, S. B. Z., S. Islam, A. Huda, M. Jahiruddin i M. R. Islam. "Effects of Prilled Urea, Urea Briquettes and NPK Briquettes on the Growth, Yield and Nitrogen use Efficiency of BRRI Dhan48". Asian Journal of Soil Science and Plant Nutrition, 3.06.2021, 19–27. http://dx.doi.org/10.9734/ajsspn/2021/v7i330114.
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Nitrogen is one of the most deficient plant nutrients in Bangladesh soils. The use nitrogenous fertilizer especially urea is a commonly used fertilizer for rice production but its efficiency very low about 30-40% under traditional broadcast method A field experiment was carried out in the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during Aus rice growing season of 2014 to investigate the effects of prilled urea, urea briquettes and NPK briquettes on the growth, yield, and nitrogen use efficiency of BRRI dhan48. There were six treatments as T1 [check (N0P16K42], T2 [Urea briquette (one-3.4 g) (N52P16K42)], T3 (Urea briquette (one-2.7 g (N78P16K42)], T4 [NPK briquette (one-3.4g)(N51P13K32], T5 [Prilled urea (N78P16K42)] and T6 [NPK briquettes(two-2.4 g briquettes (N78P15K42)]. The experiment was laid out in a Randomized Complete Block Design (RCBD) with six treatments and four replications. Prilled urea was applied in two equal splits application; at 8 days after transplanting (DAT) and the second dose after 38 DAT, while for urea briquettes and NPK briquettes were deep placed (8-10 cm depth) at 8 DAT between four hills at alternate rows. Water samples were collected for every 7 consecutive days and analyzed for NH4-N. The results showed that the NH4-N concentration in floodwater reached to maximum on day 2 in PU treated plots and then decreased with time, while the urea briquettes and NPK briquettes treated plots slowly produced NH4-N over the growth period. The highest grain yield of 4.75 t ha-1 (69% over control) was obtained in the treatment T3 [Urea briquette (one-2.7g) (N78P16K42)]. The treatment T3 also produced the highest straw yield of 5.49 t ha-1. The maximum apparent N recovery and the maximum N use efficiency were found in the treatment T4 [NPK briquette (one-3.4g) (N51P13K32)]. It appeared that the deep placement of urea briquettes and NPK briquettes reduced N-losses and enhanced the recovery of applied N as well as N use efficiency in comparison with PU application.
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Aronsson, Helena, Lotten Wahlund, Malin Lovang, Ebba Hellstrand, Åsa Odelros i Eva Salomon. "Phosphorus load in outdoor areas for laying hens and capacity of phosphorus retaining materials to reduce the environmental impact". Organic Agriculture, 15.02.2021. http://dx.doi.org/10.1007/s13165-021-00349-z.
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AbstractThis study investigated manure loads in outdoor paddocks for laying hens and the capacity of two phosphorus (P) retaining materials for reducing leaching from manure in areas with high hen density. Inventories on two commercial farms during 2 years (2017 and 2018) of the impact of hens (groups of 3000 hens) on vegetation, as a proxy for land use by hens, showed that 16–21% of outdoor area in grassland paddocks and 22–39% of area in a forest paddock were used by the hens. Sand and limestone were tested as P retention materials in areas with high manure load in a field study during the outdoor season for laying hens (May 1 to October 31 in 2018). The materials were placed on the ground (0.2 m deep bed, 3.3 m wide) outside the pop-hole in paddocks with 76 hens. The average numbers of hens outdoors were recorded at 9 am and 3 pm daily. There was no significant difference between the materials concerning distribution of hens, and they seemed not to prefer any material more than the other. When cylinders containing the spent materials were exposed to simulated rainfalls in a laboratory study, the P concentrations in drainage water were high for all materials, including a control with gravel (58–136 mg PO4-P L−1 and 130–197 mg total-P L−1). On average, 14% of manure P retained in the sand and limestone materials was leached after 100 mm of simulated rainfall. Thus, these materials may act as physical filters for P in manure, but to reduce the risk of P losses to waters during the following winter, they need to be removed from the paddocks and preferably used as potential P fertilizers on arable land.