摘要
近地表土壤水分条件对农田化学物质输出过程和地表水质有很大影响。以黄土区缓坡耕地为研究对象,利用地下供水和前期降雨措施改变坡面近地表土壤水分条件,通过室内模拟降雨试验研究坡面水土流失和土壤溶质(NO3-、PO43-、K+和B r-)的迁移特征。结果表明地下供水对土壤溶质迁移影响最大,水土流失量和溶质地表流失量显著高于其它处理。前期降雨处理地表径流量和泥沙量大于对照处理,而径流和泥沙溶质平均浓度相对较低。NO3-和B r-坡面迁移的主要载体是地表径流,PO43-主要随侵蚀泥沙迁移,K+两者兼有。地下供水坡地出现明显的土壤侵蚀后,地表径流中PO43-和K+的浓度急剧增加。土壤初始含水量较高的地下供水和前期降雨坡地是土壤侵蚀和吸附态溶质流失的敏感区,对应的等效径流迁移深度也较大。
Near-surface soil and water conditions have great influences on agricultural chemicals release and transport, which can be tested by the surface water quality nearby. Soil and water conditions are changed by groundwater supply and antecedent precipitation. According to the resuits of artificial rainfall on the loess gentle slope, the soil erosion, release and transport charac- teristics of soil nitrate, phosphorus, potassium and bromine are studied. Soil water conditions and overland flow are greatly impacted by groundwater supply, leading to the most loss amount of soil erosion and solutes load. The surface runoff amount of groundwater supply plot is 2. 03 and 2. 67 times more than that of the antecedent precipitation and check ones, respectively ; the sediment of the former is 46. 98 and 82. 20 more than that of the latter, respectively; and the net PO4^3- loss amount of the former is 121.70 and 268.68 more than that of the other two plots, respectively. There is more soil erosion amount of the antecedent precipitation plot than that of check one, while the mean solute concentration in runoff and sediment of the former is less than the latter. Soil nitrate and bromine are usually transported by surface runoff, while phosphorus by sediment, and potassium by both runoff and sediment. When the acute soil erosion of groundwater supply plot takes place, the solute concentration in runoff climbs again, especially that of the adsorbed PO4^3- and K ＋ is higher than the content during the initial runoff period. The hazards of soil erosion and solutes loss are urged by groundwater supply and antecedent precipitation, with high soil initial water content, and the effective transport depth of runoff for them is more than that of check one.
出处
《自然资源学报》
CSCD
北大核心
2009年第4期743-751,共9页
Journal of Natural Resources
基金
国家自然科学基金(40801102
90610030)
国家水体污染控制与治理科技重大专项基金(2008ZX0701-004)
国家科技支撑计划基金(2006BAD09B06)
河南农业大学博士基金(30200297)
关键词
土壤水分条件
地表径流
土壤侵蚀
溶质迁移
影响
soil and water conditions
surface runoff
soil erosion
solutes release and transport
effect
