Fujian Normal University
National Natural Science Foundation of China（No. 31870604，32030073）and the International Cooperation Project of Fujian (No. 2019I0010)
【Objective】In the process of vegetation restoration in eroded red soil area, the accumulation rate of soil organic matter seriously restricts the improvement of productivity of Masson pine. How to solve this problem has been an inevitable development process of Masson pine in eroded red soil area. Heterotrophic respiration, an important part of soil carbon emission, is a key factor affecting soil organic carbon accumulation. Therefore, to study the effects of pine restoration on heterotrophic respiration and its sensitivity in eroded red soil areas is of great significance for us to deeply understand the carbon output process and effectively increase soil organic matter accumulation in eroded red soil areas. 【Method】 In this study, pine forests with different restoration years were selected in the eroded red soil area of south China. Different soil respiration components were separated by trenching method in unrestored land (Y0), restored for 14 years (Y14) and restored for 31 years (Y31), and the effects of restoration on soil heterotrophic respiration were studied by combining temperature, moisture and microbial factors. 【Result】 The results showed that the heterotrophic respiration (Rh) of the pine forests with different recovery years differed significantly. The Rh in site Y31 was significantly higher than that in site Y14 and Y0. The Rh in site Y0 was only 0.99 μmol.m-2.s-1, while that in site Y14 and Y31 was 2.20 and 2.80 μmol.m-2.s-1, respectively. The ratio of Rh to total soil respiration in different restoration years was 77.94% (Y0), 70.84% (Y14) and 77.35% (Y31). The temperature sensitivity (Q10) of Rh shows an increasing trend during the restoration of the pine forest, with the values in 1.58, 1.93 and 1.82, respectively. The relative contributions of Rh to total soil respiration in different recovery years are 77.94% (Y0), 70.84% (Y14), and 77.35% (Y31), respectively. The structural equation model showed that SOC, temperature and soil microbes are the main factors affecting Rh during the restoration process of masson pine forest. SOC and soil microbes are significantly correlated with Rh, while there is a negative relationship between temperature and Rh. 【Conclusion】 We concluded that the accumulation of SOC and the lack of effective increase the microorganism for the intensity of the physical protection, on the other hand, the improvement of soil environmental temperature, the continuous increase of bacteria and fungi abundance, and the increase of Proteobacteria, Ascomycota and Acidobacteria in the community further aggravate the microbes to the original strength of soil organic matter decomposition. As a consequence, the continuous increase of heterotrophic respiration related carbon emissions and thus limits the increase of carbon sequestration efficiency in Pinus massoniana forest. Therefore, the strong soil heterotrophic respiration in the eroded and degraded red soil area may be the key factor limiting the further improvement of soil organic matter.
Jiang yong meng, Deng cui, Lü mao kui, Xiong xiao ling, Li jia yu, Xie jin sheng. Changes in soil heterotrophic respiration and its temperature sensitivity during restoration of Pinus massoniana plantations in eroded red soil area.[J]. Acta Pedologica Sinica,,[In Press]