自然降雨条件下香根草生物篱对菜地土壤地表径流和氮流失的影响

Impacts of Biological Hedgerow of Vetiver on Surface Runoff and Nitrogen Loss in Vegetable Field under Natural Rainfall

通过修建径流小区,开展了自然降雨条件下香根草生物篱对种植辣椒土壤地表径流的发生及其引起的水土流失和氮素流失影响的研究。试验结果表明,在菜地土壤种植香根草生物篱能有效地降低地表径流以及减少因地表径流引起的土壤氮素流失。在辣椒种植期间,香根草生物篱种植小区的总产流量比传统辣椒种植小区的降低了41.9%。与传统辣椒种植小区相比,香根草生物篱种植小区的地表径流中NH4+-N和NO3--N流失量平均分别降低57.9%和59.7%,土壤侵蚀量平均降低64.5%,侵蚀土壤的氮流失量平均降低64.8%。试验结果还显示,降雨强度与地表径流量、地表径流NH4+-N、地表径流NO3--N、地表径流全N流失量、土壤侵蚀量和侵蚀土壤N流失量之间的相关性均达到极显著水平,这一结果说明降雨强度影响水土流失和土壤氮素流失的主要因素。

Utlizing surface runoff plots, the impacts of biological hedgerow of vetiver on surface runoff, soil and water loss and nitrogen loss in vegetable field with pepper（Capsicum annuum L. ）planted under natural rainfall were studied in this paper. The results showed that the biological hedgerow of vetiver reduced the surface runoff and nitrogen loss resulted by surface runoff in vegetable field. During the period of pepper growth, the total amount of surface runoff in the plot with vetiver planted was reduced by 41.9 % compared to that in the CK plot. The amounts of NH4^＋ -N and NO3^- -N loss with surface runoff in the plot with vetiver planted were lowered by 57.9% and 59.7% compared with that in CK plot, respectively. The amounts of soil erosion and nitrogen loss resulted by soil erosion in vetiver plot were reduced by 64.5 ; and 64.8 ;, respective- ly. The results also revealed that rainfall intensity was highly correlated with the amounts of surface runoff, NH4^＋ - N, NO3^- -N and total N loss with surface runoff, soil erosion and N loss with soil erosion. This maybe illustrate that rainfall intensity was a main factor to affect soil and water loss and soil N loss.