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

Abstract

AbstractRevegetation 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.