陕北黄土高原植被恢复对土壤理化性状的影响

为了解陕北黄土高原不同植被恢复类型对土壤理化性状的影响及其季节变化,采用完全随机设计,以陕北黄土高原恢复19年的杏树林、沙棘林、油松林和刺槐林为研究对象,以耕作相同年限农田为对照,分析不同植被恢复类型、土层和季节对土壤有机质、碱解氮、速效磷、速效钾、pH以及电导率的影响。结果表明,土壤有机质、速效磷和速效钾在不同人工林地间达到显著差异水平,人工林地土壤养分含量均高于玉米农地,杏树林和沙棘林相对较高,刺槐林相对较低。碱解氮、pH和电导率在不同人工林地间没有达到显著差异水平。随着土层加深,土壤有机质、碱解氮、速效磷和速效钾显著降低,pH和电导率土层间变化规律不一致。土壤有机质、碱解氮、速效钾和电导率在夏季和春季较高,土壤速效磷和pH在冬季和秋季较高。0~20 cm土层,有机质与碱解氮和速效钾均达到显著正相关水平;20~40 cm土层,土壤有机质与电导率呈显著正相关关系,速效磷与速效钾呈显著负相关;速效钾和电导率在各土层间均达到显著正相关水平,pH与电导率在各土层间均呈显著负相关关系。植被恢复显著提高了土壤养分,杏树林和沙棘林富集土壤养分能力优于油松林和刺槐林。

Effects of Vegetation Restoration on Soil Physicochemical Properties in the Loess Plateau of Northern Shaanxi

To study the influence of different types of vegetation restoration on soil physicochemical properties and the properties’ seasonal change in the Loess Plateau of northern Shaanxi, we used the method of completely random design, took 19-year old Prunus armeniaca forest, Hipophae rhamnoides forest, Pinus tabuliformis and Robinia pseudoacacia forest as the research objects and the cultivated land as the control, to analyze the effects of vegetation restoration types, seasons, soil depth on soil organic matter, available N, available P, available K, pH and electric conductivity. The results showed that soil organic matter, available P and available K had significant difference among different vegetation types. The content of soil nutrients of artificial forest was higher than that of corn field, higher in Prunus armeniaca forest and Hipophae rhamnoides forest, lower in Pinus tabuliformis and Robinia pseudoacacia forest. Under different vegetation types, the soil nutrients significantly decreased with the increase of soil depth. Soil organic matter, available N, available K and electric conductivity were the highest in spring and summer. Available P and pH were the highest in autumn and winter. There was a positive correlation between soil organic matter and available N and available K in 0-20 cm soil depth, a positive correlation between soil organic matter and electric conductivity and a negative correlation between available P and available K in 20-40 cm soil depth. In 0-40 cm soil depth, there was a positive correlation between available K and electric conductivity, and a negative correlation between pH and electric conductivity. In conclusion, vegetation restoration could effectively improve soil nutrient, and the soil nutrients’ content is high in Prunus armeniaca forest and Hipophae rhamnoides forest.