Soil Respiration And Litter Decomposition Of Typical Forest Types With Different Xerarch Successional Stages Of Broad-leaved Pinus Koraiensis Forest

Pimary broad-leaved Pinus koraiensis forest is a typical zonal community type in the temperate zone of China.Quercus mongolica secondary forest is one of its typical secondary forests.The study on soil respiration and the characteristics of the components of the primary broad-leaved Pinus koraiensis forest and Quercus mongolica secondary forest will be helpful in gaining insight into Xiaoxing'an Mountains spatial and temporal distribution characteristics of carbon source and sink as well as its main effect factors.The final end is to accurately evaluate the carbon balance of this region.We tested the soil respiration?R_S?of Primary broad-leaved Pinus koraiensis forest and Quercus mongolica secondary forest in 2015 and 2016,adopted procedure of quantization in the test of soil respiration components?heterotrophic respiration R_H,autotrophic respiration R_A?,and surveyed the soil temperature and soil moisture at 10 cm of the soil.We has been clear about the physical and chemical properties of soil and studied the litter decomposition.The soil respiration and its main components feature obvious seasonal variation,which is mainly influenced by temperature.The maximum of soil respiration appears in August and the minimum of soil respiration appears in May&October.The temperature at the depth of 10 cm of the soil can explain the variation of RS of 48%⁷9%.As for the temperature sensitivity,primary broad-leaved Pinus koraiensis forest's Q₁₀ value of soil respiration>Quercus mongolica secondary forest Q₁₀ value of soil respiration.While in the comparison of a single forest,Q₁₀ of R_A>Q₁₀ of R_S>Q₁₀ of R_H.The average soil respiration of R_S of the primary broad-leaved Pinus koraiensis forest and the Quercus mongolica secondary forest are 2.99 and 3.35?mol·m^-2·s^-1,respectively,the average soil respiration of R_H are 2.08 and 2.57?mol·m^-2·s^-1,respectively,while the average soil respiration of R_A are 0.96 and 1.17?mol·m^-2·s^-1,respectively.The average annual flux of R_S of the primary broad-leaved Pinus koraiensis forest and the Quercus mongolica secondary forest are 670.43 and 706.87 m^-2·a^-1 C,respectively;the average annual flux of R_H are462.92and 540.42 m^-2·a^-1 C,respectively,while the average annual flux of R_A are 188.37 and157.09 m^-2·a^-1 C,The average annual flux of R_S and R_H of Primary broad-leaved Pinus koraiensis forest is higher than that of Quercus mongolica secondary forest,and the differences are significant.Therefore,we concluded that with the xerach succession,forest carbon flux has a tendency to decrease?Quercus mongolica forest?Primary broad-leaved Pinus koraiensis forest?.Litter decomposition experiments showed that Pinus koraiensis litter decomposition constant,the half-life of,turnover period were 0.43,1.62 and 12.38 years,while the Quercus mongolica constant,half-life,turnover period were 0.53,1.29 and 9.88 years.Quercus mongolica litter decomposition rate faster than the Pinus koraiensis litter,together with the Quercus mongolica secondary forest litter production is greater than the Primary broad-leaved Pinus koraiensis forest.Thus to some extent,affect the size of the values of soil respiration.