运用川中丘陵区四种土壤母质类型5个观测点历年的数据,定义了可蚀模数和产流模数,通过关联和曲线回归分析,阐明旱作制抗水蚀的能力为聚土免耕>横坡种植>顺坡种植;坡旱地的侵蚀量 Q 和径流深 Z 与降雨量 R 的最佳回归关系:Q=a+b1nR...运用川中丘陵区四种土壤母质类型5个观测点历年的数据,定义了可蚀模数和产流模数,通过关联和曲线回归分析,阐明旱作制抗水蚀的能力为聚土免耕>横坡种植>顺坡种植;坡旱地的侵蚀量 Q 和径流深 Z 与降雨量 R 的最佳回归关系:Q=a+b1nR 和 Z=A十BR定量描述了坡地旱作制下的水土流失特征。通过比较曲线方程确定了聚土免耕、横坡种植和顺坡种植的 P 值分别为0.29,0.49和1。结果得出,坡地旱作制下的土壤侵蚀方程应修正为:Q=K(t).C(t).P.S.L·ln(R-c~^(a/b)。展开更多
By using the perturbation theories on sums of ranges of nonlinear accretive mappings of Calvert and Gupta, we study the abstract results on the existence of a solution u ∈ L^s （Ω） of nonlinear boundary value probl...By using the perturbation theories on sums of ranges of nonlinear accretive mappings of Calvert and Gupta, we study the abstract results on the existence of a solution u ∈ L^s （Ω） of nonlinear boundary value problems involving the p-Laplacian operator, where 2≤ s〈＋∞, and 2N/N＋1 〈 p ≤ 2 for N（≥ 1） which denotes the dimension of R^N. To obtain the result, some new techniques are used in this paper. The equation discussed in this paper and our methods here are extension and complement to the corresponding results of L. Wei and Z. He.展开更多
The aim of the study was to develop an index to assess the environmental risk of P loss potential in vegetable soils with chronic difference of plantation in the suburbs of Changsha, Hunan Province, China. Chemical me...The aim of the study was to develop an index to assess the environmental risk of P loss potential in vegetable soils with chronic difference of plantation in the suburbs of Changsha, Hunan Province, China. Chemical methodology was used to study soil phosphorus status and the relationships between available P in soil and potential soil leaching P. The results showed that there was a significant linear relationship between Olsen P and CaC12-P or P concentration in soil solution. Olsen P increased sharply when either CaCI2-P or P concentration in soil solution reached a certain level. It was confirmed that 80 mg kg-t of Olsen P was the critical value of soil P leaching in the vegetable soils. P leaching probability over the critical was assessed by GIS and indicator Kriging and four secondary risks of phosphorus leaching loss were defined. In the area with vegetable cropping for over 30 yr （Chenjiadu） and 10-15 planting years （Huangxingzhen）, the indices of phosphorus leaching loss risk were 3 and 2.93, respectively. These two areas belonged to strong secondary of risk of phosphate leaching loss. In the new vegetable planting field less than 2 yr （Ningxiang）, the index was 0.06, which had almost no risk of phosphorus leaching. In vegetable soils in the suburban region of Changsha, the phosphorus leaching peotential is high and the phosphorus leaching loss is related to chronic length of vegetable cropping.展开更多
文摘运用川中丘陵区四种土壤母质类型5个观测点历年的数据,定义了可蚀模数和产流模数,通过关联和曲线回归分析,阐明旱作制抗水蚀的能力为聚土免耕>横坡种植>顺坡种植;坡旱地的侵蚀量 Q 和径流深 Z 与降雨量 R 的最佳回归关系:Q=a+b1nR 和 Z=A十BR定量描述了坡地旱作制下的水土流失特征。通过比较曲线方程确定了聚土免耕、横坡种植和顺坡种植的 P 值分别为0.29,0.49和1。结果得出,坡地旱作制下的土壤侵蚀方程应修正为:Q=K(t).C(t).P.S.L·ln(R-c~^(a/b)。
基金This research is supported by the National Natural Science Foundation of China(No. 10471033).
文摘By using the perturbation theories on sums of ranges of nonlinear accretive mappings of Calvert and Gupta, we study the abstract results on the existence of a solution u ∈ L^s （Ω） of nonlinear boundary value problems involving the p-Laplacian operator, where 2≤ s〈＋∞, and 2N/N＋1 〈 p ≤ 2 for N（≥ 1） which denotes the dimension of R^N. To obtain the result, some new techniques are used in this paper. The equation discussed in this paper and our methods here are extension and complement to the corresponding results of L. Wei and Z. He.
基金supported by the National Nature Science Foundation of China (NSFC4077111 andKZCX2-YW-437)
文摘The aim of the study was to develop an index to assess the environmental risk of P loss potential in vegetable soils with chronic difference of plantation in the suburbs of Changsha, Hunan Province, China. Chemical methodology was used to study soil phosphorus status and the relationships between available P in soil and potential soil leaching P. The results showed that there was a significant linear relationship between Olsen P and CaC12-P or P concentration in soil solution. Olsen P increased sharply when either CaCI2-P or P concentration in soil solution reached a certain level. It was confirmed that 80 mg kg-t of Olsen P was the critical value of soil P leaching in the vegetable soils. P leaching probability over the critical was assessed by GIS and indicator Kriging and four secondary risks of phosphorus leaching loss were defined. In the area with vegetable cropping for over 30 yr （Chenjiadu） and 10-15 planting years （Huangxingzhen）, the indices of phosphorus leaching loss risk were 3 and 2.93, respectively. These two areas belonged to strong secondary of risk of phosphate leaching loss. In the new vegetable planting field less than 2 yr （Ningxiang）, the index was 0.06, which had almost no risk of phosphorus leaching. In vegetable soils in the suburban region of Changsha, the phosphorus leaching peotential is high and the phosphorus leaching loss is related to chronic length of vegetable cropping.
