Variability of above-ground litter inputs alters soil physicochemical and biological processes: a meta-analysis of litterfall-manipulation experiments

[摘要] Global change has been shown to alter the amount of above-ground litterinputs to soil greatly, which could cause substantial cascading effects onbelow-ground biogeochemical cycling. Despite extensive study, there isuncertainty about how changes in above-ground litter inputs affect soilcarbon and nutrient turnover and transformation. Here, we conducted ameta-analysis on 70 litter-manipulation experiments in order to assess howchanges in above-ground litter inputs alter soil physicochemical properties,carbon dynamics and nutrient cycles. Our results demonstrated that litterremoval decreased soil respiration by 34%, microbial biomass carbon inthe mineral soil by 39% and total carbon in the mineral soil by10%, whereas litter addition increased them by 31, 26 and 10%,respectively. This suggests that greater litter inputs increase the soilcarbon sink despite higher rates of carbon release and transformation. Totalnitrogen and extractable inorganic nitrogen in the mineral soil decreased by17 and 30%, respectively, under litter removal, but were not altered bylitter addition. Overall, litter manipulation had a significant impact uponsoil temperature and moisture, but not soil pH; litter inputs were morecrucial in buffering soil temperature and moisture fluctuations in grasslandthan in forest. Compared to other ecosystems, tropical and subtropicalforests were more sensitive to variation in litter inputs, as altered litterinputs affected the turnover and accumulation of soil carbon and nutrientsmore substantially over a shorter time period. Our study demonstrates thatalthough the magnitude of responses differed greatly among ecosystems, thedirection of the responses was very similar across different ecosystems.Interactions between plant productivity and below-ground biogeochemicalcycling need to be taken into account to predict ecosystem responses toenvironmental change.

[学科分类] 地球化学与岩石