内蒙古希拉穆仁草原风蚀水平观测研究

近年来,草原由于遭受不合理利用而严重退化、沙化,风蚀愈加严重。采用集沙仪和移动式风洞模拟相结合的方法,对位于阴山北麓中部的希拉穆仁草原风蚀特征进行了连续6 a的观测研究。结果表明:(1)植被是控制风蚀的决定性因素,并且植被高度对风蚀的抑制作用强于植被盖度。(2)研究区风蚀模数在围封初期很高,达到1313.7 t/(km²·a),随着植被的改善,草原风蚀逐年下降。(3)风蚀物以细沙粒为主,含量占60%以上。该地区每风蚀1000 kg土壤,同时就损失15 kg有机质,227 g速效氮,262 g速效磷和120 g速效钾,肥力损失量惊人。保护基本草原,恢复退化草地,是防治草地风蚀的最根本途径。

Observation and Research on Wind Erosion in Xilamuren Grassland Area, Inner Mongolia

Due to irrational landuse, grassland has degraded severely and wind erosion occurs remarkably in recent years. By employing sand sampler and mobile wind tunnel, an observation for 6 years was made to analyze the mechanisms of wind erosion in Xilamuren grassland, the center of North Yinshan Mountains. Results show that:(1) Vegetation is the decisive factor for controlling wind erosion and the inhibiting effect of vegetation height on wind erosion is greater than that of vegetation coverage. (2) Wind erosion modulus in the initial period of enclosure reaches 1 313.7 t/(km²·a) and with the improvement of the grassland vegetation, wind erosion decreases year by year. (3) The deflation content gives priority to fine sand particles that account for more than 60%. For every 1000 kg soil eroded by wind, 15 kg organic matter, 227 g available nitrogen, 262 g available phosphorus and 120 g available potassium lose in the region at the same time, being a tremendous fertility loss. Therefore, the protection of base grassland and restoration of degraded grassland are two fundamental approaches to control wind erosion on the grassland.