摘要
农业施肥水平和耕作方式等流域管理措施影响非点源污染物的输出.选择三峡库区黑沟小流域60种管理措施组合,即5种化肥施用水平(FL1-现用量、FL2-70%现用量、FL3-推荐用量、FL4-70%推荐用量、FL5-30%推荐用量)、4类耕作方式(CT-传统耕作、NT-免中耕、CS-等高种植、RC-留茬覆盖)和3种年降雨模式(干旱年、平水年、丰水年),基于GIS和Annualized Agricultural Nonpoint Source(AnnAGNPS)模型进行流域尺度下的年际非点源污染物模拟输出.结果表明,化肥施用水平对径流和泥沙输出没有影响,对总氮和总磷输出呈强正相关;NT、CS和RC等保护性耕作方式虽然降低了泥沙输出量,但增加了养分的输出量;泥沙输出量随年降雨量的增加而急剧增加,氮输出量几乎不随年际降雨量的增加而增加,磷输出量随年际降雨量的增加而缓幅增加,达到一定输出量时,输出增量迅速降低;FL3可削减40%的养分输出,NT削减45%泥沙输出,FL3+NT管理措施是三峡库区流域降低非点源污染输出最为经济有效的模式之一.
Sediment and its associated pollutants entering a water body can be very destructive to the ecological health of that system.Based on GIS and AnnAGNPS model,A total of 60 combinations of various management treatments including five fertilizer levels（FL1-existing,FL2-70% of existing,FL3-recommended,FL4-70% of recommended,FL5-30% of recommended）,four tillage practices（CT-conventional tillage,NT-no tillage,CS-contour strip cropping,RC-residue cover） and three kinds of annual rainfall（deficit,normal,abundant） have been evaluated.Results from model simulations indicate that runoff and sediment yield were not affected due to change in fertilizer doses,but there was a significant positive correlation between nutrient losses and fertilizer application rates;Conservation tillage practices such as NT,CS and RC would reduce sediment and sediment-bound nutrient losses significantly,they have very little benefit on soluble nitrogen and phosphorus losses.This is primarily because the increased infiltration rates resulting from those practices leads to greater losses of subsurface and return flow in the watershed.In view of feasibility and efficiency,the combination of FL3 ＋ NT was found to be the best scenario as the reductions of nutrient losses and sediment yield were about 40% and 45%,respectively.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第2期423-427,共5页
Environmental Science
基金
"十一五"国家科技支撑计划项目(2006BAD03A13
2006BAD03A07)
河南科技大学博士科研基金项目(09001445)
关键词
ANNAGNPS模型
非点源污染
三峡库区
管理措施
AnnAGNPS model
non-point source pollution
Three Gorges Reservoir area
management practices
