Effects of litter inputs on soil respiration: a meta-analysis

Abstract

Listen

Translate article

Whilst soil respiration is often increased in response to litter inputs, the magnitude of the effect and the underlying drivers remains poorly understood. We synthesized 66 recently published papers on forest ecosystems with 2436 observations using a meta-analysis approach to investigate the effect of litter inputs on soil respiration. The results showed that litter inputs had strong positive impacts on soil respiration, labile C availability, and the abundance of soil microorganisms, with less of an effect on soil moisture and temperature. The increase in soil respiration in response to litter inputs showed the following patterns: with coniferous forests (50.7%) > broad-leaved forests (41.3%) > mixed forests (31.9%). The effect also depended on stand age with middle-aged forests (53.3%) > mature forests (50.2%) > young forests (34.5%). Correspondingly, microbial biomass carbon (MBC) and dissolved organic carbon (DOC) were increased by 21.0%-33.6% and 60.3%-87.7%, respectively, in response to normal and doubled litter inputs, whilst soil respiration increased linearly with increases in DOC and MBC. Normal and doubled litter inputs increased total PLFA (Phospholipid Fatty Acid) by 6.6% and 19.7%, respectively, but decreased the fungal/bacterial PLFA ratio by 26.9% and 18.7%, respectively. Increases in soil respiration in response to litter inputs were closely related with total PLFA, fungal PLFA, bacterial PLFA, and fungal/bacterial PLFA ratio. Therefore, in addition to forest type and stand age, labile C availability, and soil microorganisms are also important factors that influence soil respiration in response to litter inputs.