Sustaining rice （Oryza sativa L.） productivity at high level is a great challenge, particularly in areas where rice productivity declines in spite of following recommended nutrient management practices. Nutrient man...Sustaining rice （Oryza sativa L.） productivity at high level is a great challenge, particularly in areas where rice productivity declines in spite of following recommended nutrient management practices. Nutrient management by integrating organic manures, inorganic fertilizers and biofertilizers may play an important role in improving and sustaining rice productivity. In this study, the authors tried to evaluate the suitable proportion of organic manures and inorganic fertilizers along with biofertilizer to maximize growth and productivity of hybrid rice on sandy-loam lateritic soils of West Bengal, India. The crop having 50% recommended dose of fertilizer （RDF） ＋ 50% recommended dose of nitrogen （RDN） through mustard oil cake （MOC） and 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer significantly increased plant height, number of tillers/m2, leaf area index （LAI）, dry matter accumulation （DMA） and crop growth rate （CGR） at initial and vital period of grain growth over those of 25% RDF ＋ 75% RDN through MOC and 100% RDN through MOC. The former two treatments also increased number of panicles/m2 and number of grains/panicle over those of only organic manuring （100% RDN） or only chemical fertilization （100% RDF） or 25% RDF ＋ 75% RDN through MOC. Crop with 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer or 50% RDF ＋ 50% RDN through MOC produced 20.2%-33.8% higher grain yield and 11.0%-33.3% greater straw yield, and paid higher gross and net returns over other treatments. This study suggests growing hybrid rice with 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer or 50% RDF ＋ 50% RDN through MOC for better growth, higher productivity and greater profit.展开更多
A higher order boundary dement method （HOBEM） is implemented for wave-current action on structures. The freeterm coefficient and Cauchy principal value （ GPV） integrals are computed by direct methods. Numerical ex...A higher order boundary dement method （HOBEM） is implemented for wave-current action on structures. The freeterm coefficient and Cauchy principal value （ GPV） integrals are computed by direct methods. Numerical experiments are carried out to validate the computation of free-term coefficient and GPV integrals. The results show that the computation precision of free-term coefficient is very high for various bodies, even with edges and corners, and the convergence speed is fast for CPV integrals for different meshes. The comparison of the second order mean drift force due to wave-current action on a uniform cylinder is made with an analytic solution. It is found that good agreement exists between the present calculation and the analytic solutions. Finally, the numerical code is applied for computing wave-current action on Snorrc TLP.展开更多
文摘Sustaining rice （Oryza sativa L.） productivity at high level is a great challenge, particularly in areas where rice productivity declines in spite of following recommended nutrient management practices. Nutrient management by integrating organic manures, inorganic fertilizers and biofertilizers may play an important role in improving and sustaining rice productivity. In this study, the authors tried to evaluate the suitable proportion of organic manures and inorganic fertilizers along with biofertilizer to maximize growth and productivity of hybrid rice on sandy-loam lateritic soils of West Bengal, India. The crop having 50% recommended dose of fertilizer （RDF） ＋ 50% recommended dose of nitrogen （RDN） through mustard oil cake （MOC） and 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer significantly increased plant height, number of tillers/m2, leaf area index （LAI）, dry matter accumulation （DMA） and crop growth rate （CGR） at initial and vital period of grain growth over those of 25% RDF ＋ 75% RDN through MOC and 100% RDN through MOC. The former two treatments also increased number of panicles/m2 and number of grains/panicle over those of only organic manuring （100% RDN） or only chemical fertilization （100% RDF） or 25% RDF ＋ 75% RDN through MOC. Crop with 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer or 50% RDF ＋ 50% RDN through MOC produced 20.2%-33.8% higher grain yield and 11.0%-33.3% greater straw yield, and paid higher gross and net returns over other treatments. This study suggests growing hybrid rice with 75% RDF ＋ 25% RDN through MOC ＋ biofertilizer or 50% RDF ＋ 50% RDN through MOC for better growth, higher productivity and greater profit.
基金This researchis supported by Research Fund for Doctoral Programs of Higher Education (Grant No.20030141006) ,and a Program for Changjiang Scholars and Innovative Research Teams in Universities (Grant No.IRT0420)
文摘A higher order boundary dement method （HOBEM） is implemented for wave-current action on structures. The freeterm coefficient and Cauchy principal value （ GPV） integrals are computed by direct methods. Numerical experiments are carried out to validate the computation of free-term coefficient and GPV integrals. The results show that the computation precision of free-term coefficient is very high for various bodies, even with edges and corners, and the convergence speed is fast for CPV integrals for different meshes. The comparison of the second order mean drift force due to wave-current action on a uniform cylinder is made with an analytic solution. It is found that good agreement exists between the present calculation and the analytic solutions. Finally, the numerical code is applied for computing wave-current action on Snorrc TLP.
