黄土高原丘陵沟壑区不同土地利用的土壤养分特征

以黄土高原丘陵沟壑区第3副区典型流域为研究区，采用实地调查、土壤采样分析和数理统计相结合的方法，基于33个样点的土壤养分数据，研究了林地、草地、果园、梯田、坡耕地5种土地利用的土壤养分特征。结果表明：土地利用方式对黄土高原丘陵沟壑区典型流域土壤有机质、全N和速效P含量的影响达到显著水平，对其他养分指标影响不明显。土壤有机质和全N含量从高到低依次为：林地＞坡耕地≈梯田＞果园＞草地，林地明显高于其他土地利用类型，而草地土壤养分最差。速效P含量从高到低依次为：果园、坡耕地、梯田、林地和草地，农业耕作植被下的速效P含量明显高于自然生态植被。研究表明：梯田作为传统的水土保持措施，在研究区具有良好的土壤保肥作用，而分布于陡坡的草地，养分保持效果在5种土地利用中最差。

Soil Nutrient Characteristics under Different Land Use Types in a Gully-hilly Region of the Loess Plateau

Land degradation is an important factor restricting social and economic sustainable development in the Loess Plateau,China.In this study,a field survey was carried out to investigate the soil nutrients under different land use types(woodland,grassland,orchard,terrace and slope farmland) in the plateau.The analyzed results of 8 soil nutrient indicators at 33 sample sites showed that the effects or impacts of different land use types on soil erosion were quite different,especially for the indicators,such as soil organic matter content,total nitrogen content and available nitrogen content.The soil organic matter content and total nitrogen content were in an obvious order of woodland > slope farmland ≈ terrace > orchard > grassland,the available P content was in an order of orchard > slope farmland > terrace > woodland > grassland,and the available P content under crops was obviously higher than that under natural vegetation.The study results revealed that terrace,as a traditional soil conservation practice,could perform very well in conserving soil nutrients,but the soil conservation capability of slope grassland was the poorest in the gully-hilly region of the Loess Plateau.