Abstract:

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.

Key words: granite parent, quartz sandy soil, economic forest modes, soil nutrient, Three Gorges Reservoir Area