Effect Of Three Kinds Of Forest Litter In Mangshan On Soil Organic Carbon And Macronutrients

Forest litter is an important source of ecosystem productivity, produced by the trees and returned to the ground, to adjust the material energy cycles maintain soil fertility and the balance of the ecosystem between the system of vegetation and soil. Litter can combine with aerial part and underground part of the forest, to improve the stability of the soil ecosystem and maintain normal function of the soil. Litter decomposition is an important part of the material circulation and energy flow in the forest ecological system, and also the bridge and the link of the biochemical cycle. In this paper, taking evergreen broad-leaved forest, mixed coniferous and broad-leaved forest, coniferous forest of mangshan national forest park forest as the research object, combining the method of the field experiment and indoor analysis, probes into the three different forest types with annual amount and standing crop of litter, litter on dynamic characteristics of a large amount of nutrient elements, litter decomposition rate and its influence to the soil nutrient, in order to further understand about ecology characteristics and natural forest production activity of different forest in mangshan district forest, for providing certain scientific basis to the steady development of the natural vegetation succession process. Through the study, the following main results:(1)There is a big difference between forest litter content of evergreen broad-leaved forest, mixed coniferous and broad-leaved forest and coniferous forest, in the process of positive succession of vegetation, the annual amount of litter size followed by evergreen broad-leaved forest (8.84t· hm-2)> mixed coniferous and broad-leaved forest (5.83t· hm-2)> coniferous forest (3.52t· hm-2). The total dry weight of evergreen broad-leaved forest litter standing crop is8.643t· hm-2, mixed coniferous and broad-leaved forest litter is5.610t· hm-2, coniferous forest is3.403t· hm-2.(2)The size order of large nutrient content of three kinds of forest litter is C>N>P>K. The organic carbon content change trend has been in a lumpy, order for evergreen broad-leaved forest> mixed coniferous and broad-leaved forest> coniferous forest. Three kinds of forest litter on the dynamic trend of N is the same as carbon.(3)Introducing Olsen’s exponential decay model Xt=Xoe-kt as amended, get the regression equation of evergreen broad-leaved forest litter decomposition rate index regression, the residual to estimate the half-life of the litter decomposition and turnover period is421and1892days respectively; By the same way, the regression equation of mixed coniferous and broad-leaved forest index isw=0.9696e-0.00062t, litter decomposition half-life and turnover period of464and2077days respectively. Coniferous forest w=0.9759e-0.00058t, litter decomposition half-life and turnover period of501and2225days respectively.(4) For evergreen broad-leaved forest and mixed coniferous and broad-leaved forest litter, Content of N in the present of decomposition early in the process of gradually rise, then the changing rule of the slow decline. Elements N of the evergreen broad-leaved forest, mixed coniferous and broad-leaved forest, coniferous forest change range12.12-17.02mg/g, respectively,15.65-19.54mg/g,14.20-16.99mg/g. In the process positive succession of vegetation, litter organic carbon content in the overall rise, namely the evergreen broad-leaved forest> mixed coniferous and broad-leaved forest>coniferous forest, content range385.98-452.66mg/g,411.33-442.88mg/g,335.13-388.58mg/g, and the three kinds of forest litter organic carbon in the process of decomposition are trend from down to up, finally the development trend of stabilizing. The content of P and N elements change law basic similar, The content of element P of the evergreen broad-leaved forest, mixed coniferous and broad-leaved forest, coniferous forest of needle respectively range4.82-5.31mg/g,4.35-4.87mg/g,4.25-4.62mg/g. The content of element K start decomposition rate faster, change is relatively stable, content is low. The element K of the evergreen broad-leaved forest, mixed coniferous and broad-leaved forest, coniferous forest of needle content range0.96-3.62mg/g, respectively,0.96-2.37mg/g,0.89-1.77mg/g.(5) The pH change between4.09to4.52and showed that significant differences between three forest types. Organic carbon of litter occurred in2012-1, the lowest of the evergreen broad-leaved forest, mixed coniferous and broad-leaved forest and coniferous forest were81.40g/kg,71.98g/kg,50.71g/kg, and total nitrogen is the lowest value appeared in2012-3, were2.31g/kg,2.08g/kg,1.71g/kg. Coniferous forest organic carbon and total nitrogen content (p<0.01) and evergreen broad-leaved forest, mixed coniferous and broad-leaved forest (p<0.01) were extremely significant difference, evergreen broad-leaved forest and mixed coniferous and broad-leaved forest and no significant difference.(6) Under the condition of different vegetation, litter content and soil organic carbon size are different, and in turn for evergreen broad-leaved forest>mixed coniferous and broad-leaved forest>coniferous forest. Different types of forest litter content relatively strong correlation with the layers of soil organic carbon and0-10cm of soil relevant, fitting R2is close to1, with the increase of soil depth, but t R2basic remain above0.8. The size of the significant effects from forest litter content to soil organic carbon is evergreen broad-leaved forest> mixed coniferous and broad-leaved forest> needle coniferous forest.Through the analysis of the above results conclude:In the process of positive succession of vegetation, litter amount and standing crop of evergreen broad-leaved forest, mixed coniferous and broad-leaved forest and coniferous forest of needle show significant difference.Three kinds of forest litter size large nutrient content are shown as:C> K> N> P, and the content of litter organic carbon, total nitrogen, total phosphorus, total potassium are evergreen broad-leaved forest> mixed coniferous and broad-leaved forest> needle coniferous forest. The litter decomposition rate of three kinds of forest showed evergreen broad-leaved forest> mixed coniferous and broad-leaved forest> needle coniferous forest. Soil pH range is small, Three kinds of forest soil organic carbon and total nitrogen change law into line. Soil organic carbon and total nitrogen content size followed by evergreen broad-leaved forest> mixed coniferous and broad-leaved forest> needle coniferous forest. Evergreen broad-leaved forest and mixed needle litter organic carbon and the change trend of soil organic carbon, on the other hand, and the coniferous forest is changing trend is consistent.Under the condition of different vegetation, litter and soil organic carbon size are not the same, and in turn for evergreen broad-leaved forest> mixed coniferous and broad-leaved forest> needle coniferous forest. The main factors affecting the correction between litter and soil organic carbon of forest types, soil layer and vegetation succession level.