短坡坡长变化对坡地风沙土产流产沙及氮磷流失的影响  

Effects of Short Slope Length on the Surface Runoff,Sediment,Nitrogen and Phosphorus of Aeolian Sandy Soils on the Slope Land

作　　者：赵光旭[1] 王全九[1,2] 张鹏宇[1] 刘艳丽[1] 柴晶[1] 

机构地区：[1]西安理工大学西北旱区生态水利工程国家重点实验室培育基地,西安710048 [2]中国科学院水利部水土保持研究所/黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100

出　　处：《水土保持学报》2016年第4期13-18,共6页Journal of Soil and Water Conservation

基　　金：国家自然科学基金重点项目(51239009);陕西省水利专项支撑计划项目(2012slkj-04;2013slkj-04)

摘　　要：通过野外水流冲刷试验,对比分析了不同坡长条件下坡面产流产沙及氮磷流失特征。结果表明,上方来水流量一定时,坡长越长,其坡面入渗量越大,径流量越小,且存在一个临界坡长,使得径流量和入渗量相当,累计径流量与坡长是负线性关系。随着坡长增加,产沙量增大,单位坡长的泥沙流失量在各坡长条件下差异并不显著(P>0.05)。累计泥沙量随着坡长增大而增大;幂函数比指数函数能更好的描述硝态氮和水溶性磷浓度变化过程;泥沙中硝态氮和有效磷的含量整体上随时间呈减小趋势。坡长越长,其养分富集率越大;随着坡长增大,存在一个临界坡长使得养分流失总量最大;土壤剖面硝态氮含量分布随着深度增大呈现出峰值特征,但是峰值存在的深度不同。土壤剖面有效磷主要积聚表层5cm以上,5cm以下有效磷含量极低。研究结果对进一步分析坡长对水土养分流失的影响具有参考价值。In this study, field experiments with water scouring were conducted to analyze the characteristics of runoff and sediment yield, and nitrogen and phosphorus loss under the conditions of different slope lengths. Results showed that with a fixed inflow rate, the amount of infiltration along slope land increased, but the runoff decreased with the increase of slope length. Notably, there was a critical slope length, where the amount of infiltration equaled to runoff, but there was the negative linear relationships between the slope length and accumulated runoff. Similarly, the sediment yield also increased with the increasing slope length, but the total loss of sediment of per unit length was not significant （P〉0.05）. The cumulative sediment yield increased with the extension of slope length. For nutrient transport, power function was superior than exponential function in describing the changing process of nitrate nitrogen and soluble phosphorus. And the concentrations of nitrate nitrogen and effective phosphorus in sediment decreased over time. The nutrient enrichment ratio became greater as slope length increased. Also, there was a critical slope length inducing the total loss of nutrient to be maximum with the increase of slope length. Besides, the concentration of nitrate nitrogen in soil profile showed a peak feature with the increase of soil depth, and the peak occurred at different depths of soil. Furthermore, soil available phosphorus mainly distributed in 0—5 cm soil layer, and it was extremely low below 5 cm of soil depth. These results mentioned above provide a reference value for further analysis on the effect of slope length on water and soil nutrient loss.

关 键 词：坡长 水流冲刷 水土流失 养分迁移 黄土坡地 

分 类 号：S157.1[农业科学—土壤学]