民勤绿洲灌区保护性耕作对土壤风蚀的影响

[目的]研究绿洲灌区保护性耕作对土壤风蚀的影响,评估保护性耕作在该区防治农田土壤风蚀的作用,为揭示相关机理提供参考。[方法]以甘肃省民勤治沙综合试验站为例,通过野外风洞试验,以传统耕作为对照,分析保护性耕作对风速廓线、风沙流结构(输沙量)、风蚀量的影响。[结果]保护性耕作近地表风速降低,大风时近地表风速随高度增加仍均匀增大,与传统耕作迅速增大不同,从而阻止风沙流结构出现"象鼻效应",输沙量在0—20 cm减小最为明显,土壤风蚀量减小。随试验风速的增大,保护性耕作土壤风蚀减小的程度越大。[结论]绿洲灌区保护性耕作能有效防止土壤风蚀,其中,立茬地表风速降低最多,输沙量、风蚀量较小,实施简便,适宜推广应用。

Effects of Conservation Tillage on Soil Wind Erosion in Minqin Oasis Irrigation Area

[Objective] The effects of conservation tillage on soil wind erosion in an oasis irrigation area were studied. The role of conservation tillage of farmland in preventing and controlling soil erosion was evaluated to provide a theoretical basis for revealing related mechanisms.[Methods] Taking Minqin Integrated Desert Control Experimental Station in Gansu Province as a study area, based on field wind tunnel test, taking traditional tillage as the control, the effects of conservation tillage on the wind speed profile, sand flow structure (sediment discharge), and amount of wind erosion were analyzed.[Results] In conservation tillage, the wind speed near the surface decreased. At a high wind speed, the near-surface wind speed increased uniformly with the increase in height. This was different from the rapid increase in traditional tillage, preventing the sand flow structure from showing the "elephant nose effect." The decrease of sediment discharge was most evident at 0-20 cm, and the amount of soil wind erosion decreased. With the increase of the test wind speed, the decrease in the degree of wind erosion by conservation tillage was greater.[Conclusion] Conservation tillage could effectively prevent field soil wind erosion in oasis irrigation areas. The decreasing wind speed of standing stubble was maximum, and the sediment discharge and rate of soil wind erosion were low. The standing stubble method was easy to implement and is suitable for promotion and application.