黄土高原自然植被恢复对土壤质量的影响

Effects of natural vegetation restoration on soil quality on the Loess Plateau

本文从土壤物理、化学和生物因子等方面综合考虑，运用土壤质量综合指数模型，计算土壤质量综合指数。定量化评价黄土高原自然植被恢复对土壤质量的影响，期望为该区植被恢复对土壤质量的影响提供理论指导，促进当地生态环境重建工作的进展。研究结果表明：1）与农田相比，植被恢复对土壤容重、水稳性团聚体、pH、电导、有机碳、全氮和微生物量碳、氮影响显著，对含水量、无机碳含量影响居中，对土壤粘粒、砂粒含量、全磷影响不显著。2）与农田相比，植被恢复后，土壤质量综合指数（SQI）值在0～10cm和10～20cm均有较大幅度的提高，0～10em比10-20cm增幅更大。3）当地农田土壤质量处于低（Ⅴ）水平，草地处于较低（Ⅳ）水平，灌木林和混交林处于中等（Ⅲ）水平，山杨和辽东栎林处于较高（Ⅱ）水平。草地恢复对于提高土壤质量的效果较差，林地恢复对提高土壤质量的效果相对最佳。

Considered soil physical, chemical and biological factors, using comprehensive index model of soil quality to calculate the soil quality index and assess the characteristics of vegetation restoration types on soil quality quantitatively. This study would provide scientific guidance about the effect of vegetation restoration on soil quality and promote the eco-environment reconstruction on the Loess Plateau. The results showed that： 1） Compared with farmland, the effect of vegetation restoration on soil bulk density, water stable aggregates, pH, electric conductivity, organic carbon, total nitrogen, soil microbial biomass carbon and soil microbial biomass nitrogen is greater, the effect of vegetation restoration on soil water content and inorganic carbon content is middle, the effect of vegetation restoration on the clay, sand and total phosphorus is little. 2） Compared with farmland, after the vegetation restoration, the soil quality index （SQI） value in 0-10 cm and 10-20 cm were greatly improved, and the SQI of 0-10 cm is rose more than the SQI of 10-20 cm, soil quality has all improved. 3） Soil quality of farmland is in low level （ Ⅴ ）, grassland is in lower level （ Ⅳ ）, shrub-forest and mixed-forest are in middle level （Ⅲ）, Poplar Forest and Oak Forest is in high level （Ⅱ）. The effect of grassland restoration on improving soil quality is poorer, while the effect of forest restoration on improving soil quality is the best.