不同耕作方式对内蒙古旱作农田土壤侵蚀的影响

Effects of tillage mode on soil erosion of rain-fed cropland in Inner Mongolia

研究黄河流域内蒙古黄土高原丘陵区农田土壤侵蚀状况,对本区域生态农业建设具有重要的意义。试验于2006年在内蒙古呼和浩特市清水河县进行,设免耕(NT)、免耕覆盖(NS)和传统耕作(CT)3种耕作处理方式,种植作物为胡麻和燕麦,观测了全年降雨量和地表水径流量及土壤流失量。结果表明:免耕覆盖及免耕能显著减少降雨对土壤的侵蚀,与传统耕作相比,免耕覆盖处理的燕麦地地表水径流量和土壤的流失量分别减少21.9%和88.3%;3种耕作方式的土壤侵蚀量均受到坡度的影响,并随着坡度的增大而增大,相同环境条件下,不同作物存在一定差异;通过对3种耕作方式下,胡麻和燕麦田土壤侵蚀量与降雨量的关系符合幂函数,且拟合优度良好,均>0.9。

A field experiment was conducted in the Qingshuihe County of Inner Mongolia to study the soil erosion of rain-fed cropland under effects of different tillage modes,which would be of significance to the construction of ecological agriculture in the hilly regions of Inner Mongolia.Three treatments,i.e.,no-tillage（NT）,no-tillage with straw mulch（NS）,and conventional tillage（CT）,were installed,and the test crops were Sesamum indicum and Avena fatua.The annual precipitation,runoff,and soil loss were measured.Compared with CT,treatments NT and NS could markedly reduce soil erosion,e.g.,the runoff and soil loss in treatment NS were decreased by 21.9% and 88.3%,respectively.Topography had great effects on soil erosion.In general,the soil erosion was increased with increasing gradient.Under the same topographic condition,the soil erosion differed with crop species.The relationships between precipitation and soil loss under the three tillage modes fitted power function,with R^2〉0.9.