黄土丘陵区不同土地利用方式水土流失及养分保蓄效应研究

对黄土丘陵沟壑区安塞水土保持试验站3种草本、3种灌木、4种乔木、1种农田共计11种不同土地利用方式径流小区进行径流和侵蚀泥沙观测，并分别分析其养分含量。研究黄土丘陵区不同土地利用方式水土流失及养分保蓄效应。结果表明，试验区2003年草本的年均径流量为1248m^3／km^2。灌木为843m^3／km^2。乔木为2079m^3／km^2，农田为10672m^3／km^2；草本的年均土壤侵蚀模数为4．6t／km^2，灌木为1．0t／km^2。乔木为2．6t／km^2，农田为169．5t／km^2。2003年乔木的径流年均氮素损失量5．68kg／km^2，灌木为3．32kg／km^2，草本为2．49kg／km^2，农田为10．80kg／km^2，乔木的径流年均P2O5损失量为0．29kg／km^2，灌木为0．22kg／km^2。草本为0．17kg／km^2，农田为0．49kg／km^2。乔木的侵蚀泥沙年均氮素损失量为2．69kg／km^2，灌木为1．18kg／km^2．草本为7．51kg／km^2，农田为139．95kg／km^2；乔木的侵蚀泥沙年均P2O5损失量为1．51kg／km^2，灌木为0．54kg／km^2，草本为2．78kg／km^2，农田为259．25kg／km^2。在本研究区注意发展和恢复草灌植被，使之尽快起到水土保持作用；另外，乔、灌、草土地利用方式相对农田对径流和侵蚀泥沙有很好的养分保蓄效应。

Influence of Different Land Use Types on Soil Erosion and Nutrition Care Effect in Loess Hilly Region

The plot experiment of 11 land use types include 3 herb land, 3 shrub land, 4 arbor land and 1 farmland at Ansai soil and water conservation research station in loess hilly region were observed. Runoff datum and runoff and sediment nutrition content were analyzed in order to research the influence of different land use types on soil erosion and nutrition care effect. The obtained results showed that the mean runoff amount of herb land use type was 1 248 m^3/km^2, shrub was 843 m^3/km^2, arbor was 2 079 m^3/km^2, farmland was 10 672 m^3/km^2,t he mean sediment amount of herb land use type was 4.6 t/km^2, shrub was 1.0 t/km^2, arbor was 2.6 t/km^2, farmland was 169. 5 t/km^2, the mean runoff N amount of arbor land use type was 5.68 kg/km^2, shrub was 3.32 kg/km^2,herb was 2.49 kg/km2, farmland was 10. 80 kg/km^2, the mean runoff P2O5 amount of arbor land use type was 0. 29 kg/km^2, shrub was 0. 22 kg/km^2, herb was 0. 17 kg/km^2 Farmland was 0. 49 kg/km^2. The mean sediment N amount of arbor land use type was 2.69 kg/km^2, shrub was 1.18 kg/km^2,herb was 7.51 kg/ km^2, farmland was 139.95 kg/km^2. The mean runoff P2O5 amount of arbor land use type was 1.51 kg/km^2, shrub was 0. 54 kg/km^2, herb was 2.78 kg/km^2, farmland was 259.25 kg/km^2 So the herb and shrub vegetation should be rehabilitated and developed quickly in order to decrease soil erosion in loess hilly region. On the other hand, the arbor, shrub, herb land use types have good nutrition care effect compare with farmland.