黄土塬区土地利用方式对土壤主要理化性质的影响

通过对陕西长武4种典型土地利用方式下0~500 cm土层土壤主要理化性质分析，以明确土地利用方式对土壤理化性质的影响。结果表明：农田、果园土壤有机质、全氮含量显著高于荒地和刺槐林地，土壤粘粒含量与土壤容重呈显著负相关关系，与土壤饱和导水率呈显著正相关关系；农田0~100 cm土层土壤容重达1.44 g·cm^-3，显著高于同深度荒地（1.27 g·cm^-3）、果园（1.38 g·cm^-3）、刺槐林地（1.32 g·cm^-3）土层；400~500 cm土层土壤含水量为刺槐林地（86 g·kg^-1）<果园（113 g·kg^-1）<荒地（152 g·kg^-1）<农田（165 g·kg^-1）；果园和刺槐林地0~500 cm土层土壤平均饱和导水率分别为0.37、0.36 mm·min^-1，显著高于农田（0.25 mm·min^-1）和荒地（0.23 mm·min^-1）。退耕还林（草）导致土壤容重降低、饱和导水率增加，有助于降水入渗，但退耕后深层土壤有干燥化的倾向。

Effects of land use patterns on soil physical and chemical properties in the Loess Plateau

To understand the impact of land use patterns on soil physical and chemical properties, the principal physical and chemical properties of 0~500 cm soil under four typical land uses in Changwu, Shaanxi Province were measured and analyzed. The results showed that the contents of soil organic matter and total nitrogen in farmland and orchard were significantly higher than those in the wasteland and black locust forest lands. The content of soil clay was significantly negatively correlated with soil bulk density and positively correlated with soil saturated hydraulic conductivity. The bulk density of 0~100 cm soil in farmland was 1.44 g·cm^-3, which was significantly higher than that in the wasteland (1.27 g·cm^-3), orchard (1.38 g·cm^-3) and black locust lands (1.32 g·cm^-3). The soil water content of 400~500 cm showed an order of black locust forest (86 g·kg^-1) < orchard (113g·kg^-1) < wasteland (152 g·kg^-1) < farmland (165 g·kg^-1). The average saturated hydraulic conductivity for the 0~500 cm soils inorchard and black locust land were 0.37 mm·min^-1 and 0.36 mm·min^-1, respectively, which were significantly higher than that in farmland (0.25 mm·min^-1) and wasteland (0.23 mm·min^-1). The implementation of grain for green project led to the decrease of soil bulk density and the increase of saturated hydraulic conductivity, which benefiting precipitation infiltration, but the deep soil had a trend of being dry after the implementation.