A long-term simulation experiment was carried out to study the effect of rice-based cropping system,green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil wa...A long-term simulation experiment was carried out to study the effect of rice-based cropping system,green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil was puddled and cropped under submerged conditions. Among all treatments, soil organic matter contents in the treatments of rice-rice-flooded fallow in winter (WF) were the highest, those in the treatments of rice-rice-astragalus (WG) came the second, and those in the treatments of rice-rice-rape (WR)were the lowest. At the same rate of green manure application, the degrees of organo-mineral complexing in soils of treatments WG and WR were higher than those of treatment WF. After 9-year rice cultivation, the state of combination of humus in heavy fraction varied with treatments. The relative content of loosely bonded humus decreased in the order of WR > WG > WF, and it correlated significantly with Se availability.展开更多
Soil properties dramatically change after long-term greenhouse vegetable cultivation, which further affects soil selenium （Se） nutritional status and plant Se uptake. An evaluation of Se availability after long-term...Soil properties dramatically change after long-term greenhouse vegetable cultivation, which further affects soil selenium （Se） nutritional status and plant Se uptake. An evaluation of Se availability after long-term greenhouse vegetable cultivation （CVC） can help in better understanding its influential factors under GVC conditions and will also facilitate further regulation of soil Se nutrition in GVC systems. Two typical GVC bases were chosen： one with clayey and acidic soil in Nanjing, southern China, and the other with sandy alkaline soil in Shouguang, northern China. Twenty-seven surface soil samples at the Nanjing base and 61 surface soil samples at the Shouguang base were collected according to cultivation duration and cultivation intensity. Soil properties including soil available Se （PO4^3--Se） and total Se （T-Se） were analyzed. The results showed that soil PO4^3--Se was significantly and negatively correlated with soil Olsen-P, available K （A-K）, and electrical conductivity （EC） at the Nanjing base. At the Shouguang base, however, no significant correlation was found between soil PO4^3--Se and Olsen-P and EC, and soil PO4^3--Se increased with increasing soil organic matter （OM）. Intensively utilized greenhouse vegetable cultivation caused significant changes in soil properties and further affected soil Se availability. Due to different management practices, the dominant factors affecting Se availability varied between the two GVC bases. At the Nanjing base, the dominant influential factor on soil Se availability was soil nutritional status, especially Olsen-P and A-K status. At the Shouguang base, where organic fertilizers were applied at high rates, soil OM was the dominant influential factor.展开更多
文摘A long-term simulation experiment was carried out to study the effect of rice-based cropping system,green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil was puddled and cropped under submerged conditions. Among all treatments, soil organic matter contents in the treatments of rice-rice-flooded fallow in winter (WF) were the highest, those in the treatments of rice-rice-astragalus (WG) came the second, and those in the treatments of rice-rice-rape (WR)were the lowest. At the same rate of green manure application, the degrees of organo-mineral complexing in soils of treatments WG and WR were higher than those of treatment WF. After 9-year rice cultivation, the state of combination of humus in heavy fraction varied with treatments. The relative content of loosely bonded humus decreased in the order of WR > WG > WF, and it correlated significantly with Se availability.
基金financially supported by the National Natural Science Foundation of China (No. 41473073)the Special Research Foundation of the Public Natural Resource Management Department of the Ministry of Environmental Protection of China (No. 201409044)
文摘Soil properties dramatically change after long-term greenhouse vegetable cultivation, which further affects soil selenium （Se） nutritional status and plant Se uptake. An evaluation of Se availability after long-term greenhouse vegetable cultivation （CVC） can help in better understanding its influential factors under GVC conditions and will also facilitate further regulation of soil Se nutrition in GVC systems. Two typical GVC bases were chosen： one with clayey and acidic soil in Nanjing, southern China, and the other with sandy alkaline soil in Shouguang, northern China. Twenty-seven surface soil samples at the Nanjing base and 61 surface soil samples at the Shouguang base were collected according to cultivation duration and cultivation intensity. Soil properties including soil available Se （PO4^3--Se） and total Se （T-Se） were analyzed. The results showed that soil PO4^3--Se was significantly and negatively correlated with soil Olsen-P, available K （A-K）, and electrical conductivity （EC） at the Nanjing base. At the Shouguang base, however, no significant correlation was found between soil PO4^3--Se and Olsen-P and EC, and soil PO4^3--Se increased with increasing soil organic matter （OM）. Intensively utilized greenhouse vegetable cultivation caused significant changes in soil properties and further affected soil Se availability. Due to different management practices, the dominant factors affecting Se availability varied between the two GVC bases. At the Nanjing base, the dominant influential factor on soil Se availability was soil nutritional status, especially Olsen-P and A-K status. At the Shouguang base, where organic fertilizers were applied at high rates, soil OM was the dominant influential factor.
