辽西地区农耕坡地土壤侵蚀影响因素及相关关系

Influencing Factors and Their Correlations of Soil Erosion on Sloping Farmland in Western Liaoning

为探讨辽西地区坡耕地土壤侵蚀规律,减少和防止水土流失的发生,2006—2010年采用径流小区定位观测天然降雨条件下坡耕地土壤侵蚀影响因素及相关关系。结果表明,随着坡度的增大,径流量和侵蚀量随之增加,并且对侵蚀量的影响大于对径流量的影响;谷子的保水护土效果优于甘薯;不同土地利用方式下土壤侵蚀量为天然荒坡地<农耕地<裸坡地;丰水年及7月份农耕地土壤侵蚀较严重;降雨因子中降雨量和最大30min雨强(I30)对侵蚀量和径流量影响较大,且随坡度的增大,二者对侵蚀量的影响增大,但对径流量的影响增加不明显。高雨强下,累积径流量与侵蚀量显著正相关,中低雨强下,二者关系不明显。随着坡度的增大,径流对土壤侵蚀影响增加。

In order to investigate the law of soil erosion on sloping farmland in western Liaoning,and to control and prevent the occurrence of soil erosion,the influencing factors and their correlations of soil erosion on sloping farmland were studied based on 5-year（2006—2010）observation in runoff plots under natural rainfall condition.The results showed that with the increase of slope gradient,soil erosion amount and runoff volume increased,and the effect of slope gradient on soil erosion amount was greater than that on runoff volume.Millet showed better soil and water conservation effect than sweet potato.Under different land use pattern,soil erosion amount listed in the following order：Natural slope wasteland〉slope cropland〉bared slope.Soil erosion was more serious in rainy year and in July.Precipitation and rainfall intensity（I30）were the main influencing factors on runoff and soil erosion amount,and the effects of precipitation and I30 on soil erosion significantly increased with the increase of slope gradient,while the effects on runoff volume did not significantly changed.The accumulated amounts of runoff and soil erosion were positively correlated under high level of rainfall intensity,while did not show obvious correlation under low and moderate rainfall intensity.The effect of runoff on soil erosion amount increased obviously along with the increasing slope gradient.