三峡库区花岗岩母质石英砂土不同经济林模式土壤养分特征研究

为了解三峡库区花岗岩母质不同经济林模式的土壤养分状况,研究了各模式下土壤pH、有机质、全量养分和速效养分的特征,并利用主成分分析法对不同模式的土壤质量进行了综合评价。结果表明,除土壤pH外,经济林土壤有机质、全氮、全磷、全钾、碱解氮、有效磷、速效钾等含量的变异较宽,为中等变异。随土壤层次的增加,各模式下土壤有机质、全氮、速效氮、速效磷和速效钾含量呈递减趋势,而全磷和全钾则存在不规律变化。土壤有机质、全氮和速效钾对经济林土壤质量的高低产生着主要作用,土壤养分综合排名表现为柑橘（精细管理）>柑橘（常规管理）>板栗林>茶园。因此,利用生物措施和精细化管理措施,可有效提高该区域经济林的土壤质量。

Different Economic Forest Modes in Quartz Sandy Soil from Granite Parent in the Three Gorges Reservoir Area: Soil Nutrient Characteristics

The paper aims to understand the soil nutrient status of different economic forest modes in quartz sandy soil from granite parent in the Three Gorges Reservoir area. We studied the characteristics of soil pH value, organic matter, the total and available nutrient contents of conventionally managed citrus orchard, tea garden, Castanea mollissima forest and precisely managed citrus orchard, and conducted comprehensive evaluation of soil quality by using principal component analysis. The results showed that: except soil pH value, the contents of organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium varied widely as medium variation; with the increase of soil layers, the contents of soil organic matter, total nitrogen, available nitrogen, available phosphorus and available potassium in different economic forest modes showed a decreasing trend, while the contents of total phosphorus and total potassium changed irregularly; the principal component analysis exhibited that soil organic matter, total nitrogen and available potassium played a major role in soil quality, and the comprehensive ranking of soil nutrients was shown as precisely managed citrus orchard>conventionally managed citrus orchard>Castanea mollissima forest>tea garden. Therefore, the combination of biological measures and precise management measures can effectively improve the soil quality of economic forests in quartz sandy soil from granite parent in the Three Gorges Reservoir area.