宁夏干旱风沙区几种植被恢复模式下的土壤养分特性

Soil Nutrient Characteristics for Different Vegetation Recovery Patterns in Arid and Sandy Areas in Ningxia

为分析植被恢复模式对土壤养分特性的影响,对宁夏干旱沙区自然封育草地、人工种植草地、自然封育+人工补播草地、人工种植灌木林地、人工种植乔木林地5种植被恢复模式下土壤的pH值、有机碳质量分数与密度、铵态氮与速效钾质量分数等进行测定。结果表明:几种植被恢复模式下土壤的pH值介于8.00～8.50,盐分质量分数0.020%～0.036%;草地土壤有机碳质量分数较林地土壤高34.5%～47.1%,有机碳密度较林地的高25.7%。几种植被模式下土壤0～20 cm土层的有机碳质量分数和碳密度最高,随土壤深度增加而减小;林地土壤的铵态氮、速效磷、速效钾质量分数比草地的高,随土壤深度增加,其含量均呈下降趋势。

Natural enclosure grassland, grassland by artificial planting, natural enclosure grassland together with artificial resowing, shrub plantation and arbor plantation were selected to study the effect of different vegetation recovery patterns on soil nutrient characteristics. Soil nutrient characteristics, such as pH value, contents of organic carbon, ammonium nitrogen and available potassium as well as organic carbon density, were determined at different soil depths. Result showed that soil pH ranged from 8. 00 to 8.50, and content of soil soluble salts from 0.020% to 0.036%. The content and density of soil organic carbon in the grasslands were 34.5% -47.1% and 25.7% higher than those in the forest lands, respectively. The soil organic carbon contents for the five vegetation recovery patterns decreased with increasing soil depth, and the highest values appeared in the soil surface layer （0-20 cm）. The contents of ammonium nitrogen and available phosphorus, and available potassium in the forest lands were higher than those in the grasslands, and decreased with increasing soil depth.