Abstract: The soil nutrient variability of different communities in semi-arid regions of Loess plateau was analyzed based on the investigation of the natural grassland enclosed for 23 years of Yunwu Mountain.The results show that the soil organic matter,total content and available nutrient of N,P,and K of Stipa bungeana.,Thymus mongolicus.,Artemisia vestita.,Carex rigescens.and degenerating S.bungeana were higher than that of unenclosed grassland.Furthermore,the longer the grassland enclosed,the larger the soil nutrient content increased;the order was as follows: 23-year enclosed grassland>12-year enclosed grassland>unenclosed grassland.At the same time,soil nutrient contents reduced gradually from the upper to lower soil layers in soil depth of 0 to 100 cm.

Key words: Grassland of Yunwu mountain, Soil profile, Nutrient variability, Semi-arid region

摘要： 以云雾山封育23年的天然草地为对象,研究黄土高原半干旱区5种群落类型土壤养分的变异特征。结果表明:在自然恢复过程中,本氏针茅(Stipa bungeana)、百里香(Thymus mongolicus)、铁杆蒿(Artemisia veslita)、白颖苔草(Carex rigescens)和退化本氏针茅,土壤有机质含量、全量及速效氮磷钾含量均比对照区显著提高,其中恢复年限愈长,养分增加幅度愈大,其次序为:封育23年>封育12年>退化草地;同时,在0~100 cm土层中,土壤养分随着土层的加深呈逐渐降低的趋势。

关键词: 云雾山草地, 土壤剖面, 养分变异, 半干旱区