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991.
Analysis of soils from 421 farmers’ fields in eastern districts of Rajasthan, India, revealed widespread deficiencies of sulfur (S; 43 to 87% fields deficient), boron (B; 25 to 100%), and zinc (Zn; 0 to 94%) in addition to phosphorus (P; 10 to 73%) and soil organic carbon (1 to 84%). An integrated approach of application of deficient S, B, and Zn along with N and P to high-yielding crop cultivars increased yield over farmers’ practice of N and P application to local cultivars by 92 to 204% in maize, 115 to 167% in pearl millet, and 150% in groundnut. Benefit-to-cost ratio of the integrated strategy varied from 3.33 to 8.03 in maize, 2.92 to 3.40 in pearl millet, and 1.15 in groundnut. The integrated approach effectively utilized scarce water in food production and increased rainwater-use efficiency at 67 to 145 kg mm?1 ha?1 from 21 to 50 kg mm?1 ha?1 under farmers’ practice.  相似文献   
992.
Field experiment was conducted to investigate the effects of BiozymeTM on soybean. Application of Biozyme granule and crop-plus spray with half of recommended nitrogen, phosphorus, and potassium (NPK) showed significant effects on all the growth and yield parameters of soybean. The greatest value for the number of trifoliate leaves (29.95 leaves plant?1), leaf area (1818.21 cm2 plant?1), leaf area index (5.946), total chlorophyll content (1.995 mg g?1 leaf fresh mass), number of nodules (35.086 plants?1), fresh and dry weight of nodules (0.664 and 0.1592 g plants?1), dry weight of root (8.564 g plants?1), pods plant?1 (69.0), seeds pods?1 (3.25), straw yield (3.122 t ha?1), biological yield (6.349 t ha?1), and grain yield (3.277 t ha?1) was observed with Biozyme crop-plus spray at 500 mL ha?1 plus half of recommended NPK and were significantly greater than control values. Biozyme crop-plus spray at 500 mL ha?1 plus half of recommended NPK performed better compared to other treatments.  相似文献   
993.
A five-year (2001/02–2006/07) field experiment was carried out on acidic clay loam soil classified as Typic Hapludalf with a maize–mustard crop sequence to study the effect of continuous application of nitrogen, phosphorus, and potassium (NPK) fertilizers alone and in combination with lime, farmyard manure (FYM), and biofertilizers on soil physical properties, soil organic carbon (SOC), soil microbial biomass carbon (SMBC), and crop yields on the hilly ecosystem of Meghalaya. Significant improvement in the soil physical conditions of the soil was observed under integrated application of organic manure and inorganic fertilizers. Addition of NPK fertilizers along with organic manure, lime, and biofertilizers increased soil organic carbon (SOC) content, aggregate stability, moisture-retention capacity, and infiltration rate of the soil while reducing bulk density. The SOC content under the treatment of 100% NPK + lime + biofertilizer + FYM was significantly greater (68.58%) than in control plots. Maize and mustard crop yields also significantly increased (4.73- and 21.09-folds, respectively) with continuous application of balanced inorganic (100% NPK) + lime + biofertilizer + FYM as compared to the control plots. However, crop yields drastically reduced under application of integrated nutrients without FYM as compared to the treatment with FYM application. Thus, the results suggest that integrated use of a balanced inorganic fertilizer in combination with lime and organic manure sustains a soil physical environment that is better for achieving higher crop productivity under intensive cropping systems in the hilly ecosystem of northeastern India.  相似文献   
994.
Productivity of rainfed finger millet in semiarid tropical Alfisols is predominantly constrained by erratic rainfall, limited soil moisture, low soil fertility, and less fertilizer use by the poor farmers. In order to identify the efficient nutrient use treatment for ensuring higher yield, higher sustainability, and improved soil fertility, long term field experiments were conducted during 1984 to 2008 in a permanent site under rainfed semi-arid tropical Alfisol at Bangalore in Southern India. The experiment had two blocks—Farm Yard Manure (FYM) and Maize Residue (MR) with 5 fertilizer treatments, namely: control, FYM at 10 t ha?1, FYM at 10 t ha?1 + 50% NPK [nitrogen (N), phosphorus (P), potassium (K)], FYM at 10 t ha?1 + 100% NPK (50 kg N + 50 kg P + 25 kg K ha?1) and 100% NPK in FYM block; and control, MR at 5 t ha?1, MR at 5 t ha?1 + 50% NPK, MR at 5 t ha?1 + 100% NPK and 100% NPK in MR block. The treatments differed significantly from each other at p < 0.01 level of probability in influencing finger millet grain yield, soil N, P, and K in different years. Application of FYM at 10 t ha?1 + 100% NPK gave a significantly higher yield ranging from 1821 to 4552 kg ha?1 with a mean of 3167 kg ha?1 and variation of 22.7%, while application of maize residue at 5 t ha?1 + 100% NPK gave a yield of 593 to 4591 kg ha?1 with a mean of 2518 kg ha?1 and variation of 39.3% over years. In FYM block, FYM at 10 t ha?1 + 100% NPK gave a significantly higher organic carbon (0.45%), available N (204 kg ha?1), available P (68.6 kg ha?1), and available K (107 kg ha?1) over years. In maize residue block, application of MR at 5 t ha?1 + 100% NPK gave a significantly higher organic carbon (0.39%), available soil N (190 kg ha?1), available soil P (47.5 kg ha?1), and available soil K (86 kg ha?1). The regression model (1) of yield as a function of seasonal rainfall, organic carbon, and soil P and K nutrients gave a predictability in the range of 0.19 under FYM at 10 t ha?1 to 0.51 under 100% NPK in FYM block compared to 0.30 under 100% NPK to 0.67 under MR at 5 t ha?1 application in MR block. The regression model (2) of yield as a function of seasonal rainfall, soil N, P, and K nutrients gave a predictability in the range of 0.11 under FYM at 10 t ha?1 to 0.52 under 100% NPK in FYM block compared to 0.18 under MR at 5 t ha?1 + 50% NPK to 0.60 under MR at 5 t ha?1 application in MR block. An assessment of yield sustainability under different crop seasonal rainfall situations indicated that FYM at 10 t ha?1 + 100% NPK was efficient in FYM block with a maximum Sustainability Yield Index (SYI) of 41.4% in <500 mm, 64.7% in 500–750 mm, 60.2% in 750–1000 mm and 60.4% in 1000–1250 mm rainfall, while MR at 5 t ha?1 + 100% NPK was efficient with SYI of 29.6% in <500 mm, 50.2% in 500–750 mm, 40.6% in 750–1000 mm, and 39.7% in 1000–1250 mm rainfall in semi-arid Alfisols. Thus, the results obtained from these long term studies incurring huge expenditure provide very good conjunctive nutrient use options with good conformity for different rainfall situations of rainfed semiarid tropical Alfisol soils for ensuring higher finger millet yield, maintaining higher SYI, and maintaining improved soil fertility.  相似文献   
995.
Various crop residues were applied to a strongly acidic tea garden soil to investigate their performance in ameliorating soil acidity. A laboratory study found the performance of crop residues on soil acid amelioration was mainly determined by the combined effect of nitrogen (N) transformation, cation exchange, and ash alkalinity. Nitrogen transformation was varied for different crop residues added, but followed N regulation, resulting in an adverse liming effect. It was assumed that during the release of ash alkalinity, cations replaced soil exchangeable acidity in soil solution, which largely diminished the liming effect of ash alkalinity. That was why soil pH was highly correlated with N transformation process. Furthermore, soil pH was positively correlated with carbon (C)/N ratios of crop residues both in low-level treatment (R 2 = 0.955) and in high-level treatment (R 2 = 0.981). Therefore, crop residues with relative high C/N ratios were considered to be more suitable for long-term pH adjustment of tea garden soils.  相似文献   
996.
Soil nitrogen (N) availability is dominated by soil water regime and the N fertilizer levels, which affect crop growth in soil water stress. To determine the optimum N applications under different degrees of soil drought, this study investigated the effects of N fertilizer levels on the crop water stress index (CWSI) of summer corn under soil water stress. A 2-year field experiment was conducted in waterproof plots in upland red soils in subtropical China. Three N fertilizer levels and seven soil water deficit levels were employed in 2007 and 2008. Nitrogen fertilization had no influence on the CWSI of the corn under slight to moderate soil drought, but the high-N treatment increased the CWSI significantly (P < 0.01) under soil drought when the mean CWSI exceeded ~0.20. The results suggested that for scheduling irrigation or predicting crop yields, the equations between CWSI and yield should be established on comparable N fertilization levels.  相似文献   
997.
Soil micronutrients were studied on loess soil with an 18-year long-term experiment. The results indicated that total soil iron and copper contents were similar under all treatments, but total soil manganese and zinc contents were significantly greater at the surface soil in the fertilized plots than in the controls, and total manganese contents were significantly greater in the whole soil profile under manure plus inorganic fertilizers than under controls. Generally, application of inorganic fertilizers had no effects on available soil micronutrient contents. The straw plus inorganic fertilizers significantly increased available manganese content at surface soil and available iron in subsurface soils. However, manure plus inorganic fertilizers significantly augmented soil-available iron contents throughout the profile, and raised available manganese, copper, and zinc contents, respectively, at surface soil relative to controls. The results suggest that long-term input of organic amendments alter the properties of soil and increase its plant-available micronutrient contents.  相似文献   
998.
ABSTRACT

Boric acid (H3BO3) fertilization as source of boron (B) is a common practice in modern agriculture, aims to correct the deficiency of this micronutrient in the Cerrado soils, and ensure the maintenance of plant metabolism for the proper crops’ development. Therefore, the aim of this work was to evaluate the effects of H3BO3 fertilization on soil and leaves during the soybean development. The experimental design was completely randomized with six replicates. The treatments were obtained in a 3 × 2 factorial scheme, fertilization with H3BO3 for three doses of B in the soil: 0 (control); 0.62 and 3.4 kg ha?1 and two foliar supplementation conditions: absence and presence. The best results for the variables length, dry mass and leaf area of soybean plants occurred with B applied to soil at doses 0 and 3.4 kg ha?1 in the absence of foliar supplementation. B content in the plants gradually increased with the micronutrient supply via soil and in leaves. Physiological apparatus of the plants was more efficient in the absence of foliar supplementation, independently of the fertilization with doses in the soil. The grain mass was up to 57% higher in the control treatment. Fertilization with H3BO3 in the soil and foliar did not improve the morphophysiological traits and the production of soybeans grown in greenhouse using clayey soil with initial B content of 0.30 mg dm?3.  相似文献   
999.
Abstract

Urea fertilisers are often applied to soil with cereal residues on the surface. Although the urease properties of soils have been investigated, the urease activities associated with cereal residues have not been thoroughly studied. Two experiments were performed to develop an acceptable urease assay for cereal residues, and to determine the effect of field exposure and concomitant saprophytic colonization on urease levels.

Two acceptable assays were found: 1) incubation in the presence of THAM‐H2SO4 buffer (pH 8), toluene, and urea, and 2) incubation only in the presence of urea. In both assays substrate concentration was 0.05 M, incubation temperature was 37°C, incubation length was 2 hours, and urea hydrolysis was determined by ammonium production. Although both assays were highly correlated (r2 = 0.992), the buffer method gave higher values. Subsequent investigations illustrated that urease activity associated with cereal residues is dramatically increased by saprophytic colonization after harvest. Freshly‐harvested winter wheat (Triticum aestivum, L.), winter rye (Secale cereale, L.), and spring wheat residues had urease activities (by the buffer method) of 4.3, 6.9, and 3.1 μmol urea g‐1 h‐1, respectively. After field exposure of 67–77 days, the urease activities had increased to 69.1, 101.9, and 74.3, respectively. The latter are far higher than literature values for U.S. mineral soils or the dried green leaves of plants.  相似文献   
1000.
作物生态适宜性定量化评价方法及通用工具   总被引:2,自引:0,他引:2  
该文研究了作物生态适宜性定量化评价方法。针对环境适宜程度的量化问题,提出了四基点生态距离计算方法,模拟了限制性因素及一般性因素的区别;在评价结果分级中,提出了二次阈值方法,将生态学意义清晰与不清晰的部分进行分离;提出了作物生态适宜性评价过程的数字化表达方法。在以上3项工作的基础上,研发了作物生态适宜性评价工具软件。以北京市冬小麦适宜性评价为例进行了应用,结果表明该评价方法和工具可以容纳主要的评价因子及主流的评价算法,具有实用性。  相似文献   
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