四子王旗草地修复试验区不同修复模式的抗风蚀试验

针对内蒙古四子王旗农牧交错区的荒漠化草地,用移动式风蚀风洞及相关配套设备对20%盖度退化草地、40%盖度带状柠条修复草地和60%盖度冰草修复草地进行原位测试,研究它们的近地表风沙运动规律,探索柠条带状配置修复和冰草喷播修复草地土壤抗风蚀的作用机理和防护效果,从而为农牧交错区荒漠化草地的风蚀防治提供技术依据。研究结果表明,在同一风速下,草地的粗糙度由大到小依次为柠条修复草地、冰草修复草地和退化草地,其中,柠条修复草地的粗糙度平均值为2.46 cm,分别是冰草修复草地和退化草地平均粗糙度的1.95和2.76倍;随着距地表高度的降低,3种草地风速均呈现减小趋势,当风洞中心风速为9 m/s时,柠条修复草地、冰草修复草地和退化草地地表在8 cm处的风速较之64 cm处的风速分别降低82.23%、66.67%和61.11%。冰草修复草地与退化草地的输沙率曲线都是随高度增加呈指数函数形式单调递减,冰草修复草地的曲线衰减更快,而柠条修复草地的输沙率最小,其输沙率在距地表约柠条带顶部的30 cm处出现极大值,在柠条带顶部以上的输沙率才会按指数规律递减。因此,带状配置柠条修复草地对风沙流的阻碍和改变作用差异显著,在低覆盖度下仍达到较好的抗风蚀效果。

Tests on Anti-wind Erosion in Different Restoration Modes of Desertification Grassland at Test Zone in Siziwang Banner

In order to provide technical basis for prevention of desertification grassland in agro-pastoral ecotone in Siziwang banner, Inner Mongolia, the in-situ test was adopted to study the blown sand movement laws and explore the mechanism and protection effect of soil wind erosion for degraded grassland with 20% coverage, repaired grassland with 40% coverage of Caragana korshinskili gapped belt scheme plantation and 60% coverage of Agropyron mongolicum randomly distributed plantation, the movable wind erosion tunnel and its supplement equipment were used. The results indicated that, at the same wind speed in the wind tunel, the descending order of soil surface roughness was C. korshinskili grassland, A. mongolicum grassland and degraded grassland. The average roughness of C. korshinskili grassland was 2.46cm, which was 1.95 times of A. mongolicum grassland and 2.76 times of degraded grassland. With the decrease of height from the ground, all the wind speeds of three grasslands were decreased, and when wind speed was 9m/s in wind tunnel, wind velocities at height of 8cm were reduced by 82.23%, 66.67% and 61.11% for C. korshinskili grassland, A. mongolicum grassland and degraded grassland compared with those at height of 64cm, respectively. The sand transport rate of C. korshinskili grassland was the smallest, and the sand transport rate curves of A. mongolicum grassland and degraded grassland were decayed in the form of exponential function along with the increase of height from ground, and the curve of degraded grassland was decayed faster. Whereas, the sand transport rate curve of C. korshinskili grassland had a maximum value at its top of 30cm, and it was exponentially decayed under its top. Therefore, the C. korshinskili grassland had significant effects on obstructing and changing wind-sand flow, and it could still achieve good anti-erosion effect at low vegetation coverage.