黑土区垄作方式对坡耕地土壤侵蚀的调控效果

Effects of Ridge Tillage Patterns on Soil Erosion of Sloping Croplands in Black Soil Region of Northeastern China

[目的]分析黑土区不同垄作方式对坡耕地土壤侵蚀的调控效果,为该区土壤侵蚀防治提供科学指导。[方法]在5°和10°坡耕地开展人工模拟降雨试验,降雨强度为50,100 mm/h,垄作方式包括:横坡垄作、垄向区田、顺垄+底部横垄和横垄+排水沟,对照处理为传统顺坡垄作。[结果]试验条件下,与顺坡垄作处理相比,横坡垄作、垄向区田、顺垄+底部横垄和横垄+排水沟处理均可有效调节径流、降低土壤侵蚀量,但不同垄作方式对径流和侵蚀的调控效果随着降雨强度和坡度的增加而减小。在5°坡耕地,横坡垄作方式对径流和侵蚀的调控效果最佳,产流率和土壤侵蚀速率分别稳定在15.0 mm/h和0.2 kg/(m^(2)·h)以下。在50,100 mm/h降雨强度下,与顺坡垄作处理相比,其径流量分别降低92.3%和83.9%,土壤侵蚀量分别降低96.8%和94.6%;而垄向区田方式对径流和侵蚀的调控效果略大于顺垄+底部横垄处理。在10°坡耕地,横坡垄作方式在降雨前期具有较好的蓄水保土作用,但在降雨后期垄体易损坏,造成土壤侵蚀量剧增;横垄+排水沟方式在降雨前期能够蓄水保土,在降雨后期能够较好地进行排水。[结论]在坡度平缓的坡耕地,应该优选横坡垄作和垄向区田方式;在坡度较大的坡耕地,应该优选横垄+排水沟方式。因此,建议根据地形坡度和降雨特征筛选适宜的垄作方式。

[Objective]The effects of ridge tillage patterns on soil erosion at sloping croplands in the black soil region of Northeastern China were analyzed in order to provide scientific guidance for soil erosion control in this region.[Methods]The simulated rainfall experiments were conducted at the sloping croplands with the 5°and 10°slope gradients.The simulated rainfall intensities were 50 and 100 mm/h.This study took the traditional up-and downslope ridge tillage as the control treatment.The ridge tillage patterns included contour ridge tillage,ridge-furrow intervals tillage,up and down slope ridge+bottom contour ridge tillage,and contour ridge+drainage ditch tillage.[Results]Under the experimental conditions,the contour ridge tillage,ridge-furrow intervals tillage,up and down slope ridge+bottom contour ridge tillage,and contour ridge+drainage ditch tillage effectively regulated runoff and decreased soil erosion,compared with control treatment.However,the regulation effect of different ridge tillage patterns on runoff and erosion decreased with the increase of rainfall intensity and slope gradient.For the 5°sloping cropland,the regulation effect of contour ridge tillage treatment on runoff and erosion was the best.The runoff rates and soil erosion rates were stable below 15.0 mm/h and 0.2 kg/(m^(2)·h).Under the rainfall intensity of the 50 and 100 mm/h,the runoff was reduced 92.3%and 83.9%respectively,and the soil erosion reduced 96.8%and 94.6%respectively,compared with the control treatments.The runoff reduction and soil erosion reduction benefits of ridge-furrow intervals tillage treatment was slightly greater than those of up and down slope ridge+bottom contour ridge tillage treatment at the 5°sloping cropland.For the 10°sloping cropland,the contour ridge tillage treatment showed better soil water storage and soil conservation capacity in the early stage of rainfall events compared with that of the other ridge tillage patterns.However,the ridges were easy to be damaged in the later stage of rainfall events,caused a rapid increase in soil erosion.In contrast,the contour ridge+drainage ditch tillage treatment could store soil and water in the early stage of rainfall events,and better drained away water in the later stage of rainfall events.[Conclusion]As to gentle sloping croplands,the contour ridge tillage and ridge-furrow intervals tillage patterns should be optimized,in the sloping farmland with steep slope,the contour ridge+drainage ditch tillage pattern should be preferred.Therefore,it is suggested to select suitable ridge tillage patterns according to slope gradients and rainfall characteristics.