黄土丘陵沟壑区林草植被恢复的减沙效益研究

对黄土丘陵沟壑区安塞县不同土地利用类型的土壤抗冲性和崩解速率特征进行了测试.结果表明,抗冲性指标和崩解速率在数值上均随着土层深度的增加而增大,表明其抵抗侵蚀能力减弱.不同利用类型0-10 cm表层土壤抗冲性和崩解速率强弱关系均为:灌木林＞草地＞乔木林＞果园＞农地,而在20-30 cm土层及40-50 cm土层有所变化.不同土地利用类型下,土壤崩解速率和土壤抗冲性之间存在着明显的直线递增关系,灌木林地土壤崩解性能随抗冲性变化速率较快,直线斜率达到0.352,而农地的崩解性能随抗冲性变化起伏最小,直线斜率为0.014 5,草地、乔木林地和果园位于两者之间.其中,乔木林地与草地二者直线斜率差异不大,在相同取样深度上具有相同的变化特征.

Effects of Sediment Reduction by Vegetation Restoration on the Loess Plateau

The characteristics of soil anti sourability and disintegration rate under different landuse types were studied in Ansai County located in the loess hill and gully area. Results showed that the anti-sourability and disintegration rate increased with soil depth increasing, indicating a decrease in soil anti-erodibility. Landuse types, in terms of soil anti-sourability and disintegration rate within 10 cm of surface soils, ranked in the descendant order of shrubbery, grassland, high-forest, orchard, and farmland, but the order changed some-what in 20-30 cm and 40.-50 cm soil layers. Under different landuses, the relationship between the anti- sourability and the disintegration rate was obviously a kind of progressively increased linearity. Soil disintegration rate for shrubbery changed fast as soil anti-sourability changed and slope of the linear equation was 0. 352 4. The linear equation slope for farmland was the smallest and is only 0. 014 5. The linear equation slopes for grassland, high-forest, and orchard were between 0. 352 4 and 0. 014 5. The difference of the linear equation slopes for grassland and high-forest was little and their variation features in the same soil depth were almost identical.