黄土丘陵区小流域土地利用和植被恢复对土壤质量的影响

土壤质量的维护和提高是全球生物圈可持续发展的重要因素之一．对黄土丘陵小流域持续利用25年后的荒草地、山杏林地、农地、油松林地、灌木林地和撂荒地土壤性状的研究结果表明，不同土地利用方式和植被恢复类型对土壤质量有很大影响；植被恢复重建和农地撂荒将增加土壤有机质含量，提高土壤质量；粗放的农业耕作措施将降低土壤质量并引起土壤退化；灌丛有明显的肥力岛屿作用；撂荒在一定程度上可以培肥土壤。随着“西部大开发”、“退耕还林还草”和生态重建工程的开展，在半干旱黄土丘陵沟壑区，建植灌木、种植牧草、农地撂荒和自然恢复是较好的生态重建和植被恢复方式。

Effects of land use and vegetation restoration on soil quality in a small catchment of the Loess Plateau

Soil quality improvement plays an important role in sustaining global biosphere. This paper studied the changes of soil quality after 25 years' land use and vegetation restoration at the Anjiapo catchment of western Loess Plateau. The analyses of soil characteristics of wasteland, almond land, farmland, pineland, shrub land and fallow land showed that different land use and vegetation restoration had different effects on soil integrated fertility index. Soil organic matter content was increased due to planting shrubs and forests. Both vegetation restoration and fallow could improve soil quality. Cultivation practice could decrease soil nutrient levels, and cropland soil was degraded. Shrub soil formed "fertile island" in the semi-arid region. Fallow could improve soil fertility to some extent. Human activities and vegetation restoration could affect soil nutrient contents after land use pattern was changed. With the launch out into the "Grand development of Western China", "Grain for Green Project" and ecological restoration, both shrub planting and fallow (natural restoration) should be the optional choices to restore soil fertility, as they could decrease soil erosion and improve soil condition at catchment scale, especially in the hilly and gully loess area. Integrative control of small catchment may be the best way for the sustainable development of the semi-arid hilly area of Loess Plateau.