Soil respiration (Rs) is the result of heterotrophic respiration (Rh) and autotrophic respiration (Ra), accounting for approximately 50-75% of total ecosystem respiration on land, which is crucial to the global carbon cycle and plays an indispensable role in biogeochemical models. With increasing global warming, understanding the response of forest soil Rh and Ra to warming is important for predicting the global carbon cycle.
In a study published in Journal of Soil Science and Plant Nutrition, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) implemented a soil warming experiment to evaluate the impact of warming on Rs in different ecosystems and the sensitivity of Rs to soil temperature (ST) and soil moisture content (SM) in diverse ecosystems. They employed a multichannel automated chamber system in both a subalpine coniferous forest in Lijiang (LJ) and a subtropical evergreen broadleaf forest in Ailao Mountain (ALS), situated in Yunnan Province, Southwest China.
The researchers used multichannel automated soil efflux chambers to evaluate the effects of different treatments on soil respiration, including control (CK), trenching (NR), and trenching with warming (NRW) in LJ and ALS. They also analyzed the effects of soil temperature and soil moisture on soil respiration and its components, and calculated the sensitivity of soil respiration to temperature.
The results showed that soil respiration in subtropical evergreen broad-leaved forest was higher than that in subalpine coniferous forest, and the proportion of heterotrophic respiration to soil respiration was significantly higher in subalpine coniferous forest than in subtropical evergreen broad-leaved forest.
Although soil temperature and soil moisture were the main factors controlling soil respiration in both forest ecosystems, the warming effect of heterotrophic respiration was more significant when considering carbon cycle models. The greater warming effect of heterotrophic respiration in subalpine coniferous forest was due to lower temperatures, less easily decomposable organic matter, and slower litter decomposition rates in this forest.
"Our findings have important implications for understanding the contribution of soil respiration to global carbon cycling in forest ecosystems under climate warming,” said ZHANG Yiping of XTBG.
Contact
ZHANG Yiping Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: yipingzh@xtbg.ac.cn
Published: 19 June2024
