植物篱和浅垄作对三峡库区坡耕地氮磷流失的影响

Effects of hedgerows and ridge cultivation on losses of nitrogen and phosphorus of slope land in Three Gorges Reservoir area

为明确三峡库区陡坡地耕作模式和植物篱防护系统对生态保护和水环境治理的影响,该文根据陡坡地特点构建了集浅垄作、少耕和残茬覆盖及残茬植物篱为一体的小麦-玉米生态耕作模式(H1),并与小麦-玉米间作香根草(H2)、小麦-玉米间作紫花苜蓿等高植物篱(H3)及常规小麦-玉米管理(H4),就化肥氮磷养分利用和氮磷坡面流失变化特点展开连续2a的小区试验。结果表明,与常规管理相比,坡耕地H1处理的作物生物产量、经济产量、肥料氮磷利用率显著提高。其中化肥磷素利用率提高0.06kg/kg。H2、H3处理对作物生物、经济产量及氮磷利用率、农学效率均未产生显著影响。与H4处理相比,坡耕地H1、H2、H3处理均能降低径流量,显著减少坡面产沙量和泥沙态磷素流失量;其中产沙量分别降低48.46%、52.26%和58.59%,泥沙态磷流失量分别降低30.58%、47.70%和44.58%。研究结果可为三峡库区坡耕地的耕作模式和生态控制提供参考。

Protective management of arable slope land plays an important role in protection of land resource and aquatic environment in Three Gorges region, China. Base on the regional natural conditions and the utilization of the arable slope land, four tillage modes with H1 （rotation of wheat and maize, wheat intercropped with horse bean, less tillage and ridge cultivation）, H2 （rotation of wheat and maize, with Vetiveria ziz anioides contour hedges intercropped at slop length interval of 5m）, H3 （rotation of wheat and maize, with alfalfa contour hedges intercropped at slop length interval of 5m）, H4 （rotation of wheat and maize, conventional management） were conducted from Oct. 2009 to Oct. 2011. The differences of apparent recovery efficiency and Agronomic efficiency of applied nitrogen and phosphorus between treatments were discussed, as well as nitrogen and phosphorus losses through slope land surface runoff were analyzed. The results showed that compared with H4, H1 increased phosphorus use efficiency by 0.06 kg/kg. No significant difference of biological and economic production, apparent recovery efficiency and agronomic efficiency of applied nitrogen and phosphorus was observed among H2, H3 and H4, which showed intercropping with Vetiveria ziz anioides or alfalfa contour hedges wouldn＇t lead to the reduction of production. Furthermore significant effects on reducing soil erosion and sediment phosphorus loss were observed for H1, H2 and H3. Compared with H4, and sediment losses for H1, H2 and H3 decreased by 48.46%, 52.26% and 58.59% respectively, and sediment phosphorus losses decreased by 30.58%, 47.70% and 44.58% respectively.