不同草被格局坡面水土-养分流失动力过程试验研究

Experimental Study on Dynamic Process of Soil Water-Nutrient Loss on Slope with Different Pattern of Grass

利用模拟降雨试验研究不同草被格局对坡面水土-养分流失过程及径流侵蚀动力的影响,分析水土-养分流失量与径流侵蚀功率、草被格局、盖度及坡面坡度等因素之间的关系。结果表明:径流侵蚀功率随着草被盖度的增大呈幂函数减小,且28°坡面的径流侵蚀功率大于相同条件下的21°坡面;在相同植被盖度、坡度和降雨条件下,径流侵蚀功率随草被覆盖格局不同而不同,表现为坡下聚集格局径流侵蚀功率>坡中>坡上;坡面水土-养分流失量随径流侵蚀功率的增加呈对数递增关系,径流侵蚀功率可作为坡面水土-养分流失过程的驱动力指标。

Laboratory rainfall experiments were performed in order to analyze the relationship between dynamic factors of water erosion and nutrient loss.The authors discussed the relationship among the grass pattern,grass coverage,gradient and runoff ersoion power.The results showed that,the runoff erosion power decreasd in the form of approximate power law function with the increase of grass coverage,the runoff ersoion power of 28°was bigger than that of 21°.With the same grass coverage,slope gradient and raining conditions,the runoff erosion power diminished from the bottom to the top of the slope surface.The sediment and the nitrogen losses increased in logarithm function along with the power augmenting.Therefore the runoff erosion power was available as a water erosion dynamic index synthesizeing the rainfall and underlying surface conditions.