旱作农业土壤水蚀条件下氮素流失效应试验研究

Experimental Study on Effect of Nitrogen Loss under Water Erosion in Dry Farmland Soil

基于旱作农业夏玉米野外径流小区试验,通过设定不同降雨类型和不同尿素施用水平,重点研究水蚀条件下土壤氮素流失效应与机理。试验结果表明,水蚀条件氮素流失水平与侵蚀程度及泥沙氮素携带能力有关,其中,泥沙侵蚀程度对氮素流失影响显著,而施肥水平对泥沙吸附氮素携带能力影响明显。侵蚀过程中泥沙、径流及表土中氮素浓度不同,泥沙吸附氮素浓度略高于表土,而远大于径流溶解氮素浓度。比较随泥沙与径流流失氮素水平发现,随泥沙流失氮素比例都高达85%以上,远大于径流携带数量,说明泥沙是氮素流失的主要载体。

To clearly understand the effect and mechanism of soil nitrogen loss with process of water erosion in dry farming areas,field runoff plot experiment on Summer Maize was carried out at different rainfall type and urea fertilizer level.The results showed that nitrogen loss amount was totally related to soil erosion degree and ability of nitrogen attached to sediment,and fertilizer level was the important reason for difference in ability of nitrogen attached to sediment.There was a difference of nitrogen concentration in sediment,runoff and top soil,which attached to sediment was a little higher than those of top soil,but much higher than those in runoff.To contrast nitrogen loss amount in sediment and runoff,sediment was the major carrier of nitrogen loss due to the result of nitrogen loss amount in sediment was 85% high of total loss,and much more than those in runoff.