北京西部山区径流小区产流产沙和土壤养分流失特征  

Water and nutrient losses on runoff plots in the mountainous area at western Beijing

作　　者：路炳军[1] 王志强[1] 

机构地区：[1]北京师范大学地表过程与资源生态国家重点实验室,地理学与遥感科学学院,北京100875

出　　处：《中国水土保持科学》2015年第6期33-39,共7页Science of Soil and Water Conservation

基　　金：国家自然科学基金“东北黑土区土壤侵蚀对土地生产力的影响”(40471082)

摘　　要：北京市周边山区水土流失综合治理程度的提高和土地利用结构的持续改变导致北京市水体富营养化的面源污染源由原来以农业土地利用为主过渡到具有各种水土保持措施的其他土地利用类型,所以研究不同水土保持措施的养分流失规律对科学地制订面源污染治理规划十分有益。采用北京市门头沟区21个径流小区9年的观测数据,分析植被覆盖和水土保持措施对径流泥沙和养分流失的影响。结果表明:1)产沙、产流量和全磷、全氮流失量之间显著相关;2)产沙、产流量和全磷、全氮流失量都与草地植被覆盖度呈指数递减关系;3)天然草地、人工草地、石坎梯田/蔬菜、树盘/人工林4种措施可显著降低产流产沙和养分流失,4种措施产沙量与裸地的比值最小(平均值为0.02),其次为全磷流失量(平均值为0.15)、产流量(平均值为0.21)和全氮流失量(平均值为0.32);4)不同措施之间,人工苜蓿草地减沙减流和减少养分流失的效益最大,其次为天然草地和树盘/人工林,再次为石坎梯田/蔬菜。平播农作物的效益最小,但与裸地相比,也分别使产沙量、产流量、全磷和全氮流失量减少了77%、34%、36%和39%。Many studies on the nonpoint pollution in Beijing area have been conducted in the last couple of decades,and the nutrient losses by rainfall erosion on farmland once were considered as the major source of nonpoint pollution in Beijing area. Nevertheless, thanks to intensified soil and water conservation measures,the ecosystems in Beijing are being recovered,and the types of land use are also changing from monotonous land use dominated by farmland to multiple land use types. This change of landuse has made it urgent to identify source areas of nonpoint pollution to establish more effective measures of nonpoint pollution control. This study analyzed the sediment yield（ SD）,runoff,total phosphorus（ TP） and total nitrogen（ TN） losses based on the data collected at the 21 runoff plots located in the mountainous area of western Beijing in 9 years from 2005-2013. Some of the plots were mainly composed of natural grasses with varying vegetation coverage,some were in the process of various soil and water conservation practices,and the rest were fallow croplands. The results showed that 1） there were significant correlations among the values of sediment yield（ SD）,runoff,TP loss and TN loss. 2） The SD,runoff,TP and TN losses decreased exponentially with the increase of grass vegetation coverage. 3） Natural grass（ NG）,planted grass（ PG）,stone terrace / vegetable（ ST）,tree disk / planted tree（ TD） can significantly decrease the SD,runoff,TP and TN losses. The average ratios of SD,runoff,TP and TN losses of the four plots withconservation measures to those of the fallow plots were 0. 02,0. 21,0. 15 and 0. 32,respectively. Among the conservation strategies,the PG was the most efficient one,with the NG and TD followed. Although crops were the least effective in controlling SD,runoff,TP and TN losses compared to other measures,they still reduced SD,runoff,TP and TN losses by 77%,34%,36% and 39%,respectively compared to fallow plots. The results of this study showed clearly that above mention

关 键 词：植被覆盖 水土保持措施 养分流失 水土保持效益 

分 类 号：S157[农业科学—土壤学]