Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has...Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs, the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture.展开更多
In this paper, we first obtain the existence of solution to some n-point boundary value problem for third-order differential equations using upper and lower solutions method. Based on the results, we explore singular ...In this paper, we first obtain the existence of solution to some n-point boundary value problem for third-order differential equations using upper and lower solutions method. Based on the results, we explore singular perturbation of another n-point boundary value problem for third-order differential equations with a small positive parameter. Finally, a uniformly valid asymptotic solution is constructed and the error estimation is given.展开更多
文摘Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs, the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture.
基金the Natural Science Foundation of Fujian Province (S0650010)Fujian Provincial Department of Sci.& Tech.(2005K028)Department of Education of FuJian Province (JB06098)
文摘In this paper, we first obtain the existence of solution to some n-point boundary value problem for third-order differential equations using upper and lower solutions method. Based on the results, we explore singular perturbation of another n-point boundary value problem for third-order differential equations with a small positive parameter. Finally, a uniformly valid asymptotic solution is constructed and the error estimation is given.