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Journal of Arid Land  2022, Vol. 14 Issue (9): 1055-1068    DOI: 10.1007/s40333-022-0102-0
Research article     
Carbon inputs regulate the temperature sensitivity of soil respiration in temperate forests
LIU Yulin1,2, LI Jiwei1,2, HAI Xuying3, WU Jianzhao3, DONG Lingbo3, PAN Yingjie1,2, SHANGGUAN Zhouping1,2,3, WANG Kaibo4,*(), DENG Lei1,2,3,*()
1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China
2University of Chinese Academy of Sciences, Beijing 100049, China
3Institute of Soil and Water Conservation, Northwest Agriculture and Forestry University, Yangling 712100, China
4State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China
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Abstract  

Litter and root activities may alter the temperature sensitivity (Q10) of soil respiration. However, existing studies have not provided a comprehensive understanding of the effects of litter and root carbon inputs on the Q10 of soil respiration in different seasons. In this study, we used the trench method under in situ conditions to measure the total soil respiration (Rtotal), litter-removed soil respiration (Rno-litter), root-removed soil respiration (Rno-root), and the decomposition of soil organic matter (i.e., both litter and root removal; RSOM) in different seasons of pioneer (Populus davidiana Dode) and climax (Quercus liaotungensis Mary) forests on the Loess Plateau, China. Soil temperature, soil moisture, litter biomass, fine root biomass, litter carbon, and root carbon were analyzed to obtain the drive mechanism of the Q10 of soil respiration in the two forests. The results showed that the Q10 of soil respiration exhibited seasonality, and the Q10 of soil respiration was higher in summer. The litter enhanced the Q10 of soil respiration considerably more than the root did. Soil temperature, soil moisture, fine root biomass, and litter carbon were the main factors used to predict the Q10 of different soil respiration components. These findings indicated that factors affecting the Q10 of soil respiration highly depended on soil temperature and soil moisture as well as related litter and root traits in the two forests, which can improve our understanding of soil carbon-climate feedback in global warming. The results of this study can provide reference for exploring soil respiration under temperate forest restoration.



Key wordslitter biomass      root carbon      soil respiration      temperate forests      Loess Plateau     
Received: 29 May 2022      Published: 30 September 2022
Corresponding Authors: WANG Kaibo, DENG Lei     E-mail: wangkb@ieecas.cn;leideng@ms.iswc.ac.cn
Cite this article:

LIU Yulin, LI Jiwei, HAI Xuying, WU Jianzhao, DONG Lingbo, PAN Yingjie, SHANGGUAN Zhouping, WANG Kaibo, DENG Lei. Carbon inputs regulate the temperature sensitivity of soil respiration in temperate forests. Journal of Arid Land, 2022, 14(9): 1055-1068.

URL:

http://jal.xjegi.com/10.1007/s40333-022-0102-0     OR     http://jal.xjegi.com/Y2022/V14/I9/1055

Fig. 1 Seasonal differences among the temperature sensitivity (Q10) of total soil respiration (Rtotal), litter-removed soil respiration (Rno-litter), root-removed soil respiration (Rno-root), and the decomposition of soil organic matter (i.e., both litter and root removal; RSOM) in Populus davidiana Dode forests (a) and Quercus liaotungensis Mary forests (b). Lowercase letters indicate the variations observed with changing seasons for the same treatment (P<0.05). Uppercase letters indicate the variations observed with varying treatments in the same season (P<0.05). Bars represent standard errors.
Factor Degree of freedom P. davidiana Q. liaotungensis
Mean square F value Mean square F value
Seasons 2 87.04 148.21*** 77.50 166.89***
Treatments 3 3.28 5.58** 2.77 5.96**
Seasons×Treatments 6 1.60 2.72* 0.82 1.78
Table 1 Analysis of variance for the factors affecting the temperature sensitivity (Q10) of soil respiration with seasons and treatments in Populus davidiana Dode forests and Quercus liaotungensis Mary forests
Fig. 2 Seasonal changes in soil respiration rate, soil temperature, and soil moisture in P. davidiana forests (a, c, and e) and Q. liaotungensis forests (b, d, and f). Bars represent standard errors.
Fig. 3 Responses of the Q10 of soil respiration to the combination of soil temperature (T) and soil moisture (M) with a bivariate non-linear model (Q10=a×M×T+b×M+c×T+d, where a, b, and c represent the coefficients of soil temperature and soil moisture, and d represents the constant) in P. davidiana forests (a, c, and e) and Q. liaotungensis forests (b, d, and f). The specific fitting equation is shown in Table 2.
Forests Season Equation R2
P. davidiana Spring Q10=0.01×M×T-0.21×M-0.03×T+1.41 0.86***
Summer Q10= -0.01×M×T+0.38×M+0.66×T-14.56 0.81***
Autumn Q10=0.005×M×T-0.07×M+0.05×T+0.07 0.92***
Q. liaotungensis Spring Q10= -0.02×M×T+0.33×M+0.30×T-4.57 0.83***
Summer Q10= -0.02×M×T+0.37×M+0.49×T-9.83 0.81***
Autumn Q10= -0.001×M×T+0.02×M+0.11×T-0.81 0.95***
Table 2 Equations of the Q10 of soil respiration with soil temperature (T) and soil moisture (M) in P. davidiana forests and Q. liaotungensis forests
Fig. 4 Relationships of the Q10 of soil respiration with soil temperature and soil moisture in P. davidiana forests (a and c) and Q. liaotungensis forests (b and d)
Forests Litter
biomass (g/m2)
Litter carbon (g/kg) Fine root biomass (g/m2) Root carbon (g/kg)
Spring Summer Autumn Spring Summer Autumn
P. davidiana 135.47
±8.33b
372.21
±3.51a
187.80
±16.60Ba
243.19
±4.37Aa
252.38
±18.88Aa
322.28
±20.00Aa
319.90
±4.54Aa
337.13
±2.42Aa
Q. liaotungensis 267.44
±10.89a
294.31
±11.95b
126.98
±10.86Bb
256.59
±10.56Aa
242.37
±17.65Aa
312.33
±20.32Aa
300.82
±10.69Aa
314.29
±7.23Ab
Table 3 Litter biomass, litter carbon, fine root biomass, and root carbon in P. davidiana forests and Q. liaotungensis forests
Fig. 5 Pearson correlation of the Q10 of soil respiration with litter biomass (LB), fine root biomass (RB), litter carbon (LC), and root carbon (RC) under different treatments and seasons. (a and b), the correlation of different treatments with LB, RB, LC, and RC; (c and d), the correlation of different seasons with LB, RB, LC, and RC. *, P<0.05.
Fig. 6 Structural equation model for evaluating the direct and indirect effects of T, M, LB, RB, LC, and RC on the Q10 of soil respiration and standardised total effect in P. davidiana forests (a and c) and Q. liaotungensis forests (b and d). The black and grey lines indicate that the correlation is significant and not significant,