保护性耕作农田对近地表风速阻挡效果分析

为了评价保护性耕作农田对近地表风速的阻挡效果，利用移动式风蚀风洞对保护性耕作农田相对于传统耕作农田的近地表风速阻挡效果进行了测试，对比分析了残茬覆盖对近地表的风速廓线挡风效果的影响。结果表明，不同残茬覆盖的保护性耕作农田近地表风速廓线明显区别于传统耕作农田，在距地表高度50 cm以下时，保护性耕作农田的风速低于传统耕作农田地表2.5～10倍；茬高30 cm的保护性耕作农田地表挡风效果的最好高度为距地表0.1 m，植被盖度90%时风速相对减小率可达76.32%；随着风洞中心风速的增大挡风效果逐渐增强，在12 m/s时达到最佳。

Analysis on resistance effect of field surface wind velocity of conservation tillage farmland

In order to evaluate wind velocity resistance effect of conservation tillage farmland, an experiment was conducted on wind velocity resistance effect of field surface under conservation tillage compared with conventional tillage by means of movable wind tunnel. The influence of wind velocity resistance effect on field surface wind velocity profile was analyzed comparatively with different crop stubbles coverage. The results indicated that the wind velocity profiles of conservational tillage farmland surface with different crop stubbles coverage were obviously different from that of conventional tillage farmland, the wind velocity of conservational tillage farmland was 2.5-10 times less than that of conventional tillage farmland below the height of field surface 50 cm. The best height of wind velocity resistance was 0.1 m from field surface. The relative wind velocity reduction ratio reached to 76.32% when its vegetation coverage was 90%. The field surface wind velocity resistance effect strengthened with the increase of wind tunnel center speed and got up to the best level when wind velocity was 12 m/s.