The Variation of Surface Soil Aggregates in the Degradation Process of the Mountain Red Earth Zone Karst
Mountain red earth is the foe-hn Paleosol influenced by the ancient climate and has been degenerated seriously in recent years.In order to understand the mechanism of degradation and the effects of mountain red earth,and the typical development zone of the mountain red earth in Karst eastern Yunnan of China is chosen to analyze the characteristics of the 0 ～ 20 cm soil surface aggregates under the four different covers in red earth zone.The results indicate that ＞ 0.25 mm water stable aggregate content (WSAC) and mean weight diameter (MWD) are gradually reduced,but the fractal dimension (FD) increased significantly in process of grassland→shrub lands→ pine wood→red bare soil.The percentage aggregate destruction (PAD) demonstrated:the law of pine wood ＜ grassland ＜ shrub lands ＜ red bare soil.The surface soil aggregate stability and other physical properties deteriorate,weakening the anti-erosion ability,reduce the organic content of mountain red earth from vegetation to no vegetation (red bare soil) degradation process.At the same time,characteristics of soil aggregates grassland,shrub lands,pine wood between change significantly,yet not accurately reflect the degradation process between vegetation.The research also indicated that The stability index of water-stable aggregates (WSAC,WMD) shows a significant negative correlation with bulk density.significant negative correlation with Particle density,and significant positive correlation with total porosity and venting quality.Soil organic matter on the stability and other physical properties of water-stable aggregates with a role in promoting.Conservation of vegetation is the key to improving the structural condition of the mountain red earth.
karstmountain red earthaggregate characteristicsfactors
NETL
NSTL
万方数据
维普
