保护性耕作对农田土壤风蚀影响的室内风洞实验研究

保护性耕作能够有效减少农田土壤风蚀。通过室内风洞实验,定量分析不同作物留茬、不同秸秆覆盖量对安塞黄绵土风蚀作用的影响。结果表明:(1)小麦留茬、玉米留茬以及秸秆覆盖都可以有效的减少风蚀。小麦秸秆覆盖量为4 210kg/hm2时土壤抗风蚀效率最高,达到95.9%;(2)风蚀量与风速成正相关关系,风蚀量随风速的变化均存在突然增大的转折点且30cm小麦留茬的转折点会明显滞后于30cm玉米留茬和裸土,30cm小麦留茬的抗风蚀效率要好于30cm玉米留茬;小麦秸秆覆盖量越大,抗风蚀效率越好;(3)随着高度的增加风蚀量逐渐减小,超过90%的风蚀量都集中在0～36cm高度范围内。随着风速的增大,0～10cm风蚀量所占比例会逐渐增加。

Impact of Conservation Tillage on Soil Wind Erosion of Farmland Based on Wind Tunnel Test

Conservation tillage can reduce soil wind erosion effectively on farmland.Quantitative analysis of the impact of different crop stubble and different straw mulch on wind erosion of loessial soil of Ansai was carried out by wind tunnel experiments in the laboratory.The results indicated that:(1) wheat stubble,corn stubble and straw mulch could reduce soil wind erosion effectively,and anti-erosion efficiency under straw mulch with 4 210 kg/hm2 was 95.9% which was the best;(2) the amount of wind erosion had a positive correlation with wind velocity,soil wind erosion increased with the increase of wind velocity,having a sudden increase of the turning point,and the turning point of 30 cm wheat stubble will be significantly lag behind the 30 cm corn stubble and bare soil.The greater coverage of wheat mulch was,the better the efficiency of anti-erosion was;(3) the amount of wind erosion will reduce gradually with the increase of the height,and over 90% of the amount of wind erosion concentrated in the range of 0~36 cm height.The proportion of wind erosion at the height of 0~10 cm would gradually rise with increasing in wind velocity.