黄土高原植被破坏与重建过程中土壤侵蚀强度变化

Change of soil erosion intensity during the course of plant destruction and plant reconstruction in the Loess Plateau

运用137Cs示踪方法,通过采集不同利用方式的坡面土壤,研究了黄土高原典型丘陵区流域植被破坏与重建过程中土壤侵蚀强度的变化情况。研究结果表明:植被破坏耕垦后使137Cs遭受了大量流失,坡耕地耕垦时间越长,土壤侵蚀愈严重;植被恢复重建有效地减轻了侵蚀强度;通过比较刺槐林、果园及封禁自然恢复的撂荒地三种植被建造方式的土壤侵蚀模数,发现以封禁自然恢复的撂荒地土壤保持效果最好,其次是刺槐林,最差的是果园,其原因与果园的管理方式有关。立地条件不同的同种植被建造方式,土壤侵蚀强度差异较大,表现为峁坡阳坡此槐林地侵蚀模数远远大于谷坡阴坡刺槐林地。根据退耕时间不同的坡地土壤侵蚀强度的变化及流域土地利用类型的变化等方面对燕沟流域土壤侵蚀变化趋势作了进一步预测。

Through sampling soils on slopes of different utilized manners, the changes of soil erosion intensity were studied in Yan- gou watershed by using 137Cs method during the course of plant destruction and land cultivation and the course of plant reconstruc- tion. The result showed that the 137Cs concentration reduced greatly because of plant destruction and land cultivation. Soil erosion on slopes became more severe with the land tillage history becoming longer. Soil erosion intensity could be lessened effectively through vegetation reconstruction. The soil erosion modulus on three kinds of vegetation reconstruction slopes were compared. The result showed that the effect of soil conservation was the best on the slopes of restoring vegetation naturally, but soil erosion on the orchard was the most severe because the management of orchard was irrational. The soil erosion intensity showed great difference under different environmental conditions with the same pattern of vegetation construction. The trend of soil erosion intensity was also forecasted in this paper.