Variations in net litter nutrient input associated with tree species influence on soil nutrient contents in a subtropical evergreen broad-leaved forest

The influence of tree species on soils has received much attention, but we know little about either the pattern and underlying mechanisms of net nutrient and carbon inputs under canopy for various tree species or the effects of net nutrient input on soil nutrient contents. To address these issues, we selected three tree species with distinct leaf sizes and arranged litter traps around the target individuals to test what affected net nutrient and carbon inputs under canopy of target individuals, and how net nutrient inputs influenced soil nutrient contents. The results showed that net litter manganese (Mn) and lignin inputs were significantly different among these tree species, as well as soil exchangeable potassium (K), available iron (Fe) and available Mn. The results also revealed that the species with the smallest sized leaves may stimulate more net Mn and lignin inputs than the species with the largest sized leaves. At the same time, net nutrient inputs correlated with soil available Fe, while the ratio of lignin to nitrogen of net litter correlated with total phosphorus contents. These results demonstrated that litter production may be the main factor deciding net nutrient and carbon inputs under different tree species' canopy, which significantly differentiated soil iron's availability.