Abstract:

【Objective】 Soil anti-erodibility is an important parameter representing material cycle and energy flow in soil ecosystem. Study on dynamics of soil anti-erodibility in the abandoned cropland in Loess Hilly area so as to understand the change and effect evaluation during process of ecological restoration is of great importance. 【Method】 The research adopted interchangeable space-time method, selected the artificial shrubs at different times as objects and chose slope cropland and the plot grown with Platycladus orientailis as the control to analyze the change of soil anti-erodibility using statistic analysis. 【Result】 The results indicated that the soil anti-erodibility under erosive slope cropland owing to human activities was low. However, there was a significant improvement in soil anti-erodibility after planting shrub. The content of soil water-stable aggregates increased gradually and small aggregates and small microaggregates transformed into aggregates with much bigger diameter. EMWD, organic matter, aggregate state, aggregate degree, dispersion coefficient increased with years while soil structure deterioration rate dropped. In general, the improvement of Hippophae rhamnoides on soil anti-erodibility was better than that of Caragana korshinkii at the same age. Correlation analysis showed that there was a significant relationship among SAI, aggregate state, aggregate degree, microaggregates and phycio-chemical property, which can be used as indicators to reflect soil quality. SAI rose significantly, and increased by 497% in 25 a compared to slope cropland, while were only 69% and 52% of Hippophae rhamnoides and Platycladus orientailis, respectively.【Conclusion】 The results suggested that disturbance from human is a major cause of poor soil anti-erodibility. It is impossible to recover soil anti-erodibility by planting shrubs in erosive slope cropland in the Loess Hilly area, but there is a way to get the climax community. SAI can reflect effiectively the change of soil anti-erodibiity during ecological restoration.

Key words: Caragana korshinskii plantation, soil anti-erodibility, soil anti-erodibility index, Loess Hilly area