Effects Of Nitrogen And Phosphorus Deposition And Litter Treatments On Nutrient Release Of Litter In Pinus Koraiensis Forest

The decomposition and nutrient release of litter as one of the main ways to maintain nutrient cycling and energy conversion in forest ecosystems,its N content,P content,C:N,C:P,N:P are important indicators of the decomposition rate and the amount of nutrient release.Litter quality and nitrogen and phosphorus deposition are important factors affecting the nutrient release of litter chemical properties,and microclimate factors,precipitation chemical composition and slope position also have direct and indirect effects on the process of litter nitrogen and phosphorus release.This paper used sample plot setting and investigation,simulated nitrogen and phosphorus deposition experiment and litter treatment,sample collection and determination and data statistical analysis.A 712-day observation experiment was conducted on Pinus koraiensis natural forest and Pinus koraiensis plantation.The research is aiming to reveal the effects of single factors of nitrogen and phosphorus deposition,litter treatment and their combination on the variation in characteristics of total nitrogen and total phosphorus content in each layer(litter layer(L),ferment layer(F),humus layer(H))of litter and the factors affecting the nutrient release of litter were briefly analyzed.The purpose of this paper is to clarify the change and release trend of litter nutrient content in different layers(L,F,H layers)by simulated nitrogen and phosphorus deposition and litter treatment,and to clarify the influencing factors.So as to provide a theoretical basis for the improvement of soil quality and sustainable management of Pinus koraiensis forest.The main research results are as follows:(1)simulated N and P deposition treatments had no significant effect on litter N content,but significantly increased P content in L and F layers of Pinus koraiensis plantation which was 30.7%and increased P content in L and F layers of natural forest which was 31.1%.(2)the addition of litter significantly decreased the N content in H layer which was 8.3%and increased the N content in L and F layers of Pinus koraiensis plantation which was 15.6%.The addition of litter significantly increased the N content in L layer which was 2.4%and decreased the N content in F and H layers of Pinus koraiensis natural forest which was 0.5%.The addition of litter significantly increased the P content in L,F and H layers of plantation which was 9.3%,and decreased the P content in L,F and H layers of natural forest which was-10.3%.(3)the difference of "litter composition" caused by different forest types had a significant effect on the chemical excitation effect,in which the addition of litter inhibited the release of N and P from Pinus koraiensis plantation with single litter composition.However,for broad-leaved Pinus koraiensis forest,the addition of litter promoted the release of N and P.(4)the release of N from the litter of the two forest types is more beneficial to the accumulation of P.(5)there is a significant correlation between litter stoichiometry and microclimate factors and chemical composition of precipitation.Litter treatment,simulated settlement treatment,slope position and temperature all had significant interaction on the eco-stoichiometric characteristics of litter.The decomposition of litter is closely related to the number of microorganisms and enzyme activity.In this paper,the changes of nutrient release from different litter layers of Pinus koraiensis natural forest and Pinus koraiensis plantation and the factors affecting its release(litter quality,nitrogen and phosphorus deposition,microclimate factors,precipitation chemical composition and topography)were analyzed.However,there is a lack of research on microbial community and enzyme activity,so the linkage and coupling relationship between soil microorganisms and litter decomposition in Pinus koraiensis forest will be further studied in the future.