Nutrient Release Dynamics In Different Mixed Methods Of Poplar And Alder Leaf-litters And Its Effects On Soil Nutrients During Decomposition

In this paper, the incubation experiments were conducted to study the effects of the mixingratios of poplar and trabeculate alder leaf litter and the litter applying ways on characteristic ofleaf litter decomposition, nutrient releasing, soil nutrient and soil microbial biomass. The resultsare as follows:1.Under the treatments of putting mixed leaf litter into soil, the decomposition coefficients,weight remaining rates of leaf litter and nutrient releasing rates were higher, the half-life ofdecomposition and time of95%decomposition is shorter than the treatments of applying leaflitter on soil surface.2. The litter applying ways had a significantly effect on soil NO3-N, soil N digestion rate andsoil N mineralization rate, but no obvious positive effects on soil NH4+-N, soil total N, soil total P,soil total K and soil microbial biomass were observed.3. Mixing ratios of leaf litter had a significantly effect on decomposition of leaf litter. Withthe ratio of trabeculate alder leaf litter increasing, the decomposition coefficients increased, whileweight remaining rates, the half-life of decomposition and time of95%decomposition decreased.4. The effect of mixing ratios on nutrient releasing appeared in the first period of leaf litterdecomposition (30d). With increasing the leaf litter ratio of trabeculate alder, the releasing ratesof total N increased, but the releasing rates of total P decreased. However, no relationship wasfound between the releasing rates of total K and increase in leaf litter ratio of alder.5. The contents of soil NO3-N, soil NH4+-N, soil MBC and MBN, soil N digestion rate andsoil N mineralization rate increased significantly with increasing of alder leaf litter when the ratioof alder leaf litter exceeds40%. However, mixing ratios of leaf litter had no significantly effectson soil total N, soil total P, soil total K and soil microbial biomass carbon-nitrogen ratio.6. Leaf litter applying ways and mixing ratios of leaf litter had significant interactions on thecontent of soil NO3-N and soil N mineralization rate.7. Adding over40%of alder leaf litter significantly affected the decomposition of themixture，suggesting that mixing over20%trabeculate alder into poplar plantation wouldsignificantly accelerate the decomposition of leaf litter of mixed plantation.