Stumps increased soil respiration in a subtropical Moso bamboo (Phyllostachys edulis) plantation under nitrogen addition

Abstract

Stumps are a key component of managed forest ecosystems, but their role in ecosystem respiration is poorly understood and commonly ignored. Nitrogen (N) addition can affect soil respiration, yet only a few studies have assessed the effect of stumps on soil respiration in intensively managed forests under increasing N deposition. Here, we report the results of a 7-year field experiment to investigate soil respiration rates with stumps of three ages (Rst, 1, 3, and 5 years after cutting, referred to as A1, A3, and A5, respectively) and without stumps (Rs) in response to different N addition rates (0, 30, 60, and 90 kg N ha−1 yr−1) in a subtropical Moso bamboo (Phyllostachys edulis) plantation in Zhejiang Province, China. The mean Rst rates of the three ages were significantly higher than Rs rates in all treatments. The mean Rst rate and temperature sensitivities (Q10-stump) of A5 were significantly lower than those of A1 and A3 under the control treatment, whereas the opposite was observed under the N addition treatments. Compared with the control treatment, N addition significantly increased the mean Rst rate of three ages by 7.02%−145.79% but significantly reduced the Q10-stump of A1 (4.69%−27.37%) and A3 (8.63%−12.88%). The temperature and microbial biomass carbon of the stump soil were significantly and positively related to Rst. These results suggested that the remaining stumps significantly enhanced soil CO2 emission in Moso bamboo plantations and that N addition could significantly promote Rst. Furthermore, the annual soil CO2 efflux in Moso bamboo plantations was significantly underestimated if the impact of the remaining stumps on soil respiration was not fully considered, especially with N addition. Therefore, soil CO2 emission in plantation ecosystems with remaining stumps and their response to increasing atmospheric N inputs need to be considered to better understand future forest CO2 emission.