Effects of pH Stress on Chinese-fir Seedling Growth and Physiology under Allelochemicals of Several Tree Species

After Chinese-fir seedlings were treated by aqueous extract of Cunninghamia lanceolata, Schima superba and Pinus massoniana for six years, the content of pH value, N and K of soil in the basin, biomass, content of chlorophyll and total phoyosynthetic rate were analyzed. The results showed that: compared to the treatments with other tree species, aqueous extract of Schima superba and Pinus massoniana had positive allelopathic effects on pH value, content of N and K of soil in the basin, biomass, content of chlorophyll and total phoyosynthetic rate; compared to the control, the treatment of Schima superba had positive effect on N content, other tree species had inhibiting effect on N and K content; as far as seedling growth and physiological index were concerned, all the tree species had positive effect on growth and physiological index compared to control.