To correctly partition the components of soil respiration, it is important to quantify interaction between litter decomposition and rhizosphere activity. However, few studies have investigated this interaction in forest ecosystems.

Using experimental data collected from a subtropical montane cloud forest (24°32′N, 101°01′E; 2,480 m above sea level) in Yunnan, SW China, Prof. ZHANG Yiping and his team of Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to test the hypothesis that litter decomposition and rhizosphere activity had a positive interaction effect on soil respiration. They also hypothesized negative effects of litter decomposition and rhizosphere activity on the temperature sensitivity of soil respiration.

   They established four treatments: control (CK), litter removal (NL), trenching (NR) and trenching together with litter removal (NRNL).They measured soil CO₂ efflux, soil temperature, and soil water content once a month over two years. Soil respiration was divided into four components: the decomposition of basic soil organic matter (SOM), litter respiration, root respiration, and the interaction effect between litter decomposition and rhizosphere activity. A two-factor regression equation was used to correct the value of soil CO₂ efflux.

    Though the interaction between litter decomposition and rhizosphere activity had no effects on temperature sensitivity, it had a significant positive effect on soil respiration. Their finding of an interaction effect on soil respiration suggested a way to identify the contribution of soil organic matter to soil respiration and thereby enabled an improved understanding of the carbon cycle on the regional scale. Litter decomposition had no effect on the temperature sensitivity of soil respiration, whereas rhizosphere activity had a strong effect. Together, they had no significant interaction effect on temperature sensitivity.

   The study entitled “Influence of interactions between litter decomposition and rhizosphere activity on soil respiration and on the temperature sensitivity in a subtropical montane forest in SW China” has been published online in Plant and Soil.