Stand ages adjust fluctuating patterns of soil respiration and decrease temperature sensitivity after revegetation

Abstract

Revegetation plays an essential role in controlling soil erosion and influencing soil respiration (Rs) by changing the vegetation coverage and soil biochemical characteristics. Soil respiration and its temperature sensitivity (Q10) have been studied comprehensively. However, the effect of stand age after revegetation on Rs and Q10 remains unclear. We selected four stands (i.e., eroded hillslopes [EBs] and 0‐ to 5‐yr, 5‐ to 10‐yr, and 10‐yr apple orchards) to investigate the changes in Rs and Q10 values. A soil CO2 flux system (Li‐8100) was used to measure Rs in situ from July 2018 to December 2018 in the Luoyugou watershed on the Chinese Loess Plateau. The average Rs rate showed decreased and increased periods with stand age. Changes in Rs were mainly induced by soil nutrient status, which accounted for 44.5% of the heavy weight in principal component analysis. The Q10 values decreased with stand age after revegetation and followed the order EB (4.96) > 0‐ to 5‐yr apple orchard (3.02) > 5‐ to 10‐yr apple orchard (2.25) > 10‐yr apple orchard (1.67). Our results suggest that Rs is substantially influenced by fungal richness and soil microbial biomass carbon (C), and the Q10 values are explained by the nonmetric multidimensional scaling ordinations of bacteria, which in turn are influenced by labile organic C. We demonstrate that converting EBs to apple orchards could be an effective way to decrease Rs and Q10 values. The fluctuating patterns of Rs with stand age should be considered when accurately evaluating the global C balance and predicting future climate change.

Components of Soil Respiration and Its Temperature Sensitivity in Four Reconstructed Soils

“…Many studies believed that soil temperature were the main factors affecting soil respiration. It can explain seasonal changes in soil respiration [39,40]. In this study, the soil respiration and soil temperature of four reconstructed soils was exponentially correlated, which was consistent with the research conclusions of most scholars [41,42].…”

How do soil microbes exert impact on soil respiration and its temperature sensitivity?

“…The temperature sensitivity of R S (defined as Q 10 ) was always applied to represent the response of R S to temperature change (Meyer et al ., 2018). R S and Q 10 are influenced by multiple factors (e.g., vegetation coverage, the ages of plants, soil temperature, soil moisture, soil physicochemical and microbial properties), which can be altered by land‐use change (Kreba et al ., 2013; Camara Ferreira et al ., 2016; Wang et al ., 2016; Wang et al ., 2018; Tong et al ., 2020). More specific, R S is positively associated with root biomass amount, and varied with crop types and the stand years under different land‐use types, because of the different allocation of photosynthetic products (Wang et al ., 2016; Yao et al ., 2019; Tong et al ., 2020).…”

“…R S and Q 10 are influenced by multiple factors (e.g., vegetation coverage, the ages of plants, soil temperature, soil moisture, soil physicochemical and microbial properties), which can be altered by land‐use change (Kreba et al ., 2013; Camara Ferreira et al ., 2016; Wang et al ., 2016; Wang et al ., 2018; Tong et al ., 2020). More specific, R S is positively associated with root biomass amount, and varied with crop types and the stand years under different land‐use types, because of the different allocation of photosynthetic products (Wang et al ., 2016; Yao et al ., 2019; Tong et al ., 2020). Furthermore, the different quality and quantity of substrate, soil carbon degrading enzymes secreted by microbes and the microbial community structure can also result in the shifted R S and Q 10 (Fang et al ., 2014; Camara Ferreira et al ., 2016; Zhang et al ., 2016b; Wang et al ., 2018; Zhang et al ., 2020).…”

Components of respiration and their temperature sensitivity in four reconstructed soils

“…Although water content and temperature have been established to be the main environmental factors influencing soil respiration in Chinese farmland ecosystems, this respiration and its components are characterized by differential responses to variations in temperature and water content 30 . The findings of numerous studies have indicated that soil temperature is the main factor influencing soil respiration, which is clearly reflected in the observed seasonal changes 31 , 32 . Consistent with the opinion of a majority of scholars 33 , 34 , we detected an exponential correlation between soil respiration and soil temperature among the four assessed reconstructed soils.…”