降雨强度和坡度对土壤氮素流失的影响  

Effects of Rainfall Intensity and Slope Gradient on Soil Nitrogen Loss

作　　者：潘忠成[1] 袁溪[1] 李敏[1] 

机构地区：[1]北京林业大学环境科学与工程学院水体污染源控制技术北京市重点实验室,北京100083

出　　处：《水土保持学报》2016年第1期9-13,共5页Journal of Soil and Water Conservation

基　　金：国家"十二五"水专项"城市地表径流减控与面源污染削减技术研究"(2013ZX07304-001)

摘　　要：采用人工模拟降雨的方法,研究了不同雨强（30,50,65,100mm/h）和坡度（0°,5°,10°）下粘质土坡面土壤氮素流失过程,以及雨强、坡度对单位面积土壤氮素流失量的影响。结果表明：（1）降雨过程中,随着雨强和坡度的增大,氮素流失的浓度和总量都会相应增加,且雨强和坡度越大,氮素流失浓度变化越快,径流浓度稳定时间越早;（2）不同雨强下坡度与单位面积土壤氮素流失量呈线性相关,且随着雨强的增大,坡度对单位面积土壤氮素流失量的影响变小;不同坡度下雨强与单位面积氮素流失量的线性关系显著,当雨强一定时,坡度的改变对氮素流失量的变化速率影响不大;（3）雨强和坡度与单位面积氮素流失量之间有显著的线性关系,相关系数达到0.978 9～0.982 0;（4）相同条件下,雨强对氮素流失量的影响比坡度大;（5）在降雨过程中,累积径流量与3种形态氮的累积流失量之间有显著的线性关系,相关系数达到0.914 5～0.961 1。Through the artificial rainfall simulation method,we studied the nitrogen loss process of clayey soil under the different rainfall intensities（30mm/h,50mm/h,65mm/h and 100mm/h）and the conditions of different slope gradients（0°,5°,10°）,and the effects of rainfall intensity and slope gradient on soil nitrogen loss per unit area.The results showed that：（1）With the increases of rainfall intensity and slope gradient,the concentration and total amount of nitrogen loss increased in the process of rainfall.The higher the rainfall intensity and slope gradient were,the faster the change of the concentration of the nitrogen loss happened and the earlier the runoff concentration become stable.（2）Under the different rainfall intensities,there were linear relationships between slope gradient and soil nitrogen loss amount per unit area,and with the increase of rainfall intensity,the effect of slope gradient on soil nitrogen loss amount per unit area decreased.Under the conditions of different slope gradients,there were significant linear relationships between rainfall intensity and soil nitrogen loss amount per unit area.When the rainfall intensity was constant,the change of slope gradient had little effect on the rate of change of the nitrogen loss amount.（3）The loss amount of nitrogen per unit area showed significant linear relationships with rainfall intensity and slope gradient,and the correlation coefficient reached 0.978 9～0.982 0.（4）Under the same condition,rain intensity showed more significant effect on nitrogen loss than slope gradient.（5）There was a significant linear relationship between cumulative runoff and cumulative loss of 3nitrogen forms in the process of rainfall,and the correlation coefficient reached 0.914 5～0.961 1.

关 键 词：模拟降雨 降雨强度 坡度 氮素流失 

分 类 号：S157.1[农业科学—土壤学]