Aboveground litter inputs determine carbon storage across soil profiles: a meta-analysis

Abstract

Aims Aboveground plant litter inputs are important sources of soil carbon (C). We aimed to establish how experimentally altered litter inputs affect soil C to 1-m depth across different ecosystems, and over different timeframes. MethodsWe performed a meta-analysis of 237 studies across 248 sites worldwide to assess the influence of treatment magnitude, treatment duration, initial soil C content, and climate on the response of soil C to altered aboveground litter inputs. ResultsOverall, soil C content was lower under litter removal, but higher under litter addition compared to controls. The effects of litter manipulation were apparent throughout the soil profile and were related to treatment magnitude. Soil C content declined markedly with increasing duration of litter removal, whereas the positive effect of litter addition attenuated over time. Cropland management practices (bare fallow or additional straw incorporation) had similar effects on soil C to litter removal and addition treatments. ConclusionsOur study reveals rapid and consistent changes in soil C content with altered litter inputs and provides important insights into plant residue management to enhance soil C sequestration. We highlight the need for long-term experiments, with a greater focus on the processes underpinning soil C storage in different ecosystems.

Changes in plant inputs alter soil carbon and microbial communities in forest ecosystems

“…These results suggest that, without exogenous C inputs from plants, microbial decomposition of SOM will cause continuous loss of soil C, especially in the long term (Figure 6; Figure S9; Dove et al, 2019). Under litter addition, the response of SOC showed a significant increasing trend with duration ( p = .029), in accordance with a previous meta‐analysis (Xu et al, 2021). However, duration had a limited explanation for the variations in SOC responses ( R 2 = .046), particularly when the data with the longest duration were excluded from the regression analysis ( R 2 = .011; Figure S9).…”

“…In contrast to litter input rate, the initial SOC in the DIRT network experiments is much higher (58 g kg −1 vs. 41 g kg −1 ; Table S5), which, thus, may lead to a relatively small response of SOC to litter addition. Alternatively, soils with high initial SOC may have a limited capacity to sequester additional C (Xu et al, 2021). The overall significant positive response of SOC pool to litter addition in our present study suggested that aboveground litter inputs can cause a net increase in SOC storage despite the litter‐induced priming (5.3%) of native SOM decomposition (Figure S8).…”

“…Global changes can alter both above‐ and belowground plant inputs via regulating plant productivity and C allocation, which, thus, can affect soil C and microbial communities via changing plant inputs into the soil (Figure 1; Lajtha, Townsend, et al, 2014; Whalen et al, 2021). However, neither of these two meta‐analyses considers belowground root alterations (Xu, Liu, et al, 2013, 2021). As such, the general patterns of how alterations in above‐ and/or belowground plant inputs affect soil C and its fractions, and microbes, the possible linkages among such effects and underling mechanisms remain unclear in widely distributed forest ecosystems.…”

Afforestation With Tropical N-Fixing Species in The Brazilian Atlantic Rainforest: Carbon and Nitrogen in The Soil Profile

“…5). The species were organized in different groups, where C. tomentosum is more associated with d 13 Xu et al 2021). Due to the relatively short time after pasture conversion to the N-xing stands, the soil C and N in the subsoil are probably derived from the forest vegetation even before the pasture.…”

Litter Removal Increases Plant Carbon Inputs to Soil in Pinus Massoniana Plantation

“…In recent decades, forest litter and net primary productivity are altered by global environmental changes, such as increasing atmospheric carbon dioxide concentrations (Song et al 2019), warming (Li et al 2017;Quan et al 2019) (Huang et al 2016), and atmospheric nitrogen deposition (Du et al 2019;He et al 2021). Variation in litter inputs to soil would impact the amount of C and nutrients entering the soil system and thus the amount of C and nutrients internally cycled in forest plantations (Huang and Spohn 2015;Sayer et al 2011;Sayer et al 2020;Xu et al 2021 ). This impact can feedback to tree growth and exert profound effects on plant productivity and litter production.…”