保护性措施对农田土壤风蚀影响的室内风洞模拟

为寻求合理的保护性耕作措施,试验设计了砾石覆盖、秸秆覆盖、覆盖与留茬组合的措施和4个风速等变量,研究风速、覆盖物和覆盖度与风蚀量、抗风蚀效率、风沙流结构的关系,比较多种措施之间的抗风蚀效果优劣.结果表明:1)4个设定风速下30％ ～ 90％覆盖度的秸秆覆盖的抗风蚀效率在54％ ～ 92％之间,砾石覆盖为26％～72％,30％的砾石覆盖或30％的秸秆覆盖与3种留茬高度的组合措施下,平均抗风蚀效率均在70％ ～ 78％之间；2)随着覆盖度的增加,砾石覆盖措施最小可抑制的有效风速值从8.0 m/s逐渐增大到12.5 m/s,秸秆覆盖措施从10.1m/s增加到了14.3 m/s；3)覆盖处理下0～62 cm高度内的输沙量大部分集中在0～26 cm;4)覆盖与留茬组合措施的输沙量多集中在60 cm以内.

Impact of protective measures on soil wind erosion on cropland:a indoor wind tunnel simulation

In order to find a rational conservation tillage treatment,the experiment with different measures of gravel cover,straw cover,gravel cover combined with wheat stubble,straw cover combined with wheat stubble and 4 grades of wind velocity was designed.In this experiment,the relation between wind velocity,coverage,covering material and mass of wind erosion,wind erosion resistance efficiency,sandstorm flow structure was studied,and functions of wind erosion resistance of these treatments were compared.The results showed that under conditions of 4 grades of wind velocity and coverage ranging from 30% to 90%,the anti-erosion efficiency of straw cover was in the range of 54% to 92%,gravel cover ranging from 26% to 72%,combined with 30 cm,20 cm,10 cm wheat stubble,the average anti-erosion efficiency of 30% gravel cover or straw cover changed from 70% to 78%.With the increase of coverage,the minimum inhibit effective wind speed of gravel cover gradually increased from 8.0 m/s to 12.5 m/s,while that of straw cover increased from 10.1 m/s to 14.3 m/s.Under the cover measures in the range of 0～62 cm height sediment load was mostly concentrated in 0-26 cm.For the measure of cover combined with wheat stubble the sediment load was mostly concentrated in the range of 0-60 cm.