[Fine-root character and its action mechanism of forest at its initial reestablished stage on degraded red soil]

This paper studied the fine-root character and its action mechanism of forest reestablished by different models for 10 years on a seriously degraded red soil, and analyzed their correlation with soil property. The results showed that fine-roots mostly distributed in 0-20 cm soil layer, accounted for 73.39% -87.41% of those in 0-40 cm soil layer. There were notable differences in nutrient storage of fine-roots under different reestablishment models. The fine- roots of medium density pure Pinus serotina forest had a much higher storage of total nitrogen, phosphorus and potassium, with the content of total nitrogen, phosphorus, potassium, calcium and magnesium being 84.47, 5.55, 38.42, 17.00 and 10.76 kg hm(-2), respectively. Soil organic matter, total nitrogen, available nitrogen, available potassium and pH had significant correlations with fine-root biomass (P < 0.05). The effects of fine-roots on soil physical properties mainly reflected on soil capillary porosity and total porosity. Fine-roots obviously increased the contents of > 0.25 mm and > 5 mm soil waterstable aggregates, and improved soil structure-stability. The correlations between fine-roots and soil bacteria and microbial quantities were significant.