Four Palaeolithic sites/localities were identified from the Yaoshi Basin of the UpperDanjiang River Valley,the Shangluo region,during investigations in 1995-1999,when atotal of 870 lithic artifacts were collected.Lith...Four Palaeolithic sites/localities were identified from the Yaoshi Basin of the UpperDanjiang River Valley,the Shangluo region,during investigations in 1995-1999,when atotal of 870 lithic artifacts were collected.Lithic-stratigraphic layer bearing lithic artifacts at the 95SP03 locality belongs to the upper part of the Xiehu Form deposit,suggesting thatthe site is probably in the middle to later period of the Middle Pleistocene.This earlyPalaeolithic site is about in same time range with those found in the Luonan Basin to the east.The other sites found in the region(95SP01,95SP02,and 95SP04)were identified from the Upper Pleistoence deposit,probably affiliated with Late Palaeolithic of northern China.展开更多
小流域土壤侵蚀量和养分损失量的定量研究可为南水北调水源区的生态保护、水土保持和生态补偿提供重要的依据。该文在地理信息技术(geographic information system,GIS)的支持下,应用修正通用土壤流失方程(revised universal soil loss ...小流域土壤侵蚀量和养分损失量的定量研究可为南水北调水源区的生态保护、水土保持和生态补偿提供重要的依据。该文在地理信息技术(geographic information system,GIS)的支持下,应用修正通用土壤流失方程(revised universal soil loss equation,RUSLE)估算了丹江鹦鹉沟流域的土壤侵蚀量和养分损失量,并进行了土壤侵蚀强度分级。结果表明,流域的年均土壤侵蚀模数为3140t/km2,侵蚀强度为中度。其中强度侵蚀以上的土地面积占流域总面积的24.1%,侵蚀量为4573.0t,却占年侵蚀总量的84.8%,其主要是坡度较大的坡耕地,是流域需要重点治理的区域。不同土地利用类型的土壤侵蚀量差异较大,林地、草地和农地的年均土壤侵蚀模数分别为509.7、1511.8和4606.5t/km2。林草地年侵蚀量较小,农地土壤侵蚀量占流域总侵蚀量的95.3%。坡度每增加5°,不同土地利用的土壤侵蚀模数增加量比坡长每增加5m的增加量要大1～2倍。研究区表土流失造成的全氮、全磷和有机质损失量分别为3.81、3.52和101.45t,其中农地的养分损失量最为严重。流域泥沙中全氮、全磷和有机质的年均流失模数分别为1.01、0.75和38.43t/(km2a)。该研究可为水源区水土流失和非点源污染治理以及清洁小流域建设提供科学依据。展开更多
文摘Four Palaeolithic sites/localities were identified from the Yaoshi Basin of the UpperDanjiang River Valley,the Shangluo region,during investigations in 1995-1999,when atotal of 870 lithic artifacts were collected.Lithic-stratigraphic layer bearing lithic artifacts at the 95SP03 locality belongs to the upper part of the Xiehu Form deposit,suggesting thatthe site is probably in the middle to later period of the Middle Pleistocene.This earlyPalaeolithic site is about in same time range with those found in the Luonan Basin to the east.The other sites found in the region(95SP01,95SP02,and 95SP04)were identified from the Upper Pleistoence deposit,probably affiliated with Late Palaeolithic of northern China.
文摘小流域土壤侵蚀量和养分损失量的定量研究可为南水北调水源区的生态保护、水土保持和生态补偿提供重要的依据。该文在地理信息技术(geographic information system,GIS)的支持下,应用修正通用土壤流失方程(revised universal soil loss equation,RUSLE)估算了丹江鹦鹉沟流域的土壤侵蚀量和养分损失量,并进行了土壤侵蚀强度分级。结果表明,流域的年均土壤侵蚀模数为3140t/km2,侵蚀强度为中度。其中强度侵蚀以上的土地面积占流域总面积的24.1%,侵蚀量为4573.0t,却占年侵蚀总量的84.8%,其主要是坡度较大的坡耕地,是流域需要重点治理的区域。不同土地利用类型的土壤侵蚀量差异较大,林地、草地和农地的年均土壤侵蚀模数分别为509.7、1511.8和4606.5t/km2。林草地年侵蚀量较小,农地土壤侵蚀量占流域总侵蚀量的95.3%。坡度每增加5°,不同土地利用的土壤侵蚀模数增加量比坡长每增加5m的增加量要大1～2倍。研究区表土流失造成的全氮、全磷和有机质损失量分别为3.81、3.52和101.45t,其中农地的养分损失量最为严重。流域泥沙中全氮、全磷和有机质的年均流失模数分别为1.01、0.75和38.43t/(km2a)。该研究可为水源区水土流失和非点源污染治理以及清洁小流域建设提供科学依据。
