In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwat...In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain, China. Effects of cropping duration (one, two, and three years) on soil salinity, soil solution composition, and pH in three adjacent plots were investigated in 2008. Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone. Salt accumulated on the edges of the ridges, and soil saturated-paste electrical conductivity (ECe) was higher in the edge. Concentrations of Na^+, Ca^2+, Mg^2+, Cl^-, and SO24^- in the soil increased with the soil depth as did the ECe, while HCO3 and pH had a relative uniform distribution in soil profile. As planting year increased, the ECe and soil salts in the field had a decreasing tendency, while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons. HCO3 and pH had little change with the planting year. Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for saline-sodic soils with shallow groundwater.展开更多
联合国欧洲经济委员会(ECE)的国内运输委员会负责制定汽车工业生产领域的各种法规、指令和标准。它所制定的ECE法规对参加国来说是必须遵守的,也是这些国家产品认证的依据。随着汽车保有量的增长,ECE排放法规的要求日趋严格。例如,对满...联合国欧洲经济委员会(ECE)的国内运输委员会负责制定汽车工业生产领域的各种法规、指令和标准。它所制定的ECE法规对参加国来说是必须遵守的,也是这些国家产品认证的依据。随着汽车保有量的增长,ECE排放法规的要求日趋严格。例如,对满载质量在3.5t以下(ECE R 15)和超过3.5t(ECE R 49)的汽车曾在1970年和1982年制定了相应的法规。展开更多
基金Supported by the Chinese Academy of Sciences Action Plan for the Development of Western China (No. KZCX2-XB2-13)the Chinese Academy of Sciences Knowledge Innovation Program (No. KSCX2-YW-N-003)the 100 Talents Program of Chinese Academy of Sciences
文摘In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain, China. Effects of cropping duration (one, two, and three years) on soil salinity, soil solution composition, and pH in three adjacent plots were investigated in 2008. Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone. Salt accumulated on the edges of the ridges, and soil saturated-paste electrical conductivity (ECe) was higher in the edge. Concentrations of Na^+, Ca^2+, Mg^2+, Cl^-, and SO24^- in the soil increased with the soil depth as did the ECe, while HCO3 and pH had a relative uniform distribution in soil profile. As planting year increased, the ECe and soil salts in the field had a decreasing tendency, while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons. HCO3 and pH had little change with the planting year. Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for saline-sodic soils with shallow groundwater.
文摘联合国欧洲经济委员会(ECE)的国内运输委员会负责制定汽车工业生产领域的各种法规、指令和标准。它所制定的ECE法规对参加国来说是必须遵守的,也是这些国家产品认证的依据。随着汽车保有量的增长,ECE排放法规的要求日趋严格。例如,对满载质量在3.5t以下(ECE R 15)和超过3.5t(ECE R 49)的汽车曾在1970年和1982年制定了相应的法规。