Linking soil microbial community dynamics to straw-carbon distribution in soil organic carbon

Abstract

Returning crop residues is a possible practice for balancing soil carbon (c) loss. the turnover rate of organic c from crop residues to soil c is dependent on soil microbial community dynamics. However, the relationship between any temporal changes in the soil microbial community after crop straw inputs and the dynamics of straw-c distribution in the soil organic carbon (Soc) pool remains unclear. the present study investigated the allocation of straw-c into soil dissolved organic carbon (Doc), microbial biomass carbon (MBc), particulate organic carbon (poc) and mineral-associated organic carbon (Maoc) using stable isotope probing, as well as the temporal changes in the soil bacterial and fungal communities using high-throughput sequencing. After the first 180 days of straw decomposition, approximately 3.93% and 19.82% of straw-C was transformed into soil MaOC and POC, respectively, while 0.02% and 2.25% of straw-C was transformed into soil DOC and MBC, respectively. The temporal change of the soil microbial community was positively correlated with the dynamics of straw-c distribution to Soc (R > 0.5, P < 0.05). The copiotrophic bacteria (e.g., Streptomyces, Massilia and Sphingobacterium), cellulolytic bacteria and fungi (e.g., Dyella and Fusarium, Talaromyces), acidophilic bacteria (e.g., Edaphobacter and unclassified Acidobacteriaceae), denitrifying and N-fixing microbes (e.g., Burkholderia-Paraburkholderia, Paraphaeosphaeria and Bradyrhizobium), and fungi unclassified Sordariomycetes were significantly correlated with straw-C distribution to specific SOC fractions (P < 0.05), which explained more than 90% of the variation of straw-C allocation into soils. copiotrophic, certain cellulolytic and denitrifying microbes had positively correlated with Doc-and Maoc-derived from straw, and other cellulolytic fungi (e.g., Talaromyces) and specific bacteria (e.g. Bradyrhizobium) were positively correlated with poc-derived from straw. our results highlight that the temporal change of soil microbial community structure well reflects the conversion and distribution process of straw-c to Soc fractions. Soil organic matter, the largest terrestrial carbon (C) pool, plays an important role in improving soil fertility and sustaining soil productivity 1,2. Many agricultural management practices, such as fertilizer application, straw return, and tillage, could affect the soil organic carbon (SOC) pool 3-6 , especially the labile organic carbon fractions, such as dissolved organic carbon (DOC), microbial biomass carbon (MBC) and particulate organic carbon (POC). DOC and MBC, considered to be soil active organic C, have been reported as important factors in impacting soil fertility 7,8. Moreover, the formation, migration and transformation of DOC can affect soil microbial community structure and activity 9-11 , and the formation of mineral-associated organic carbon (MaOC) 12,13 , which usually represents the largest fraction of SOC pool 14. POC has been considered as a transition state of stable organic C, which is predominantly of...

Diversity and asynchrony in soil microbial communities stabilizes ecosystem functioning

“…For instance, different N-cycling microbes exhibit temporal seasonal dynamics as they are active at different times to contribute to nitrification and denitrification processes that are also linked to plant community development ( Prosser and Nicol, 2012 ; Regan, 2017 ). Additionally, microbial community composition changes during decomposition as microbes have different resource acquisition strategies where some fast-cycling microbes acquire readily available carbon early, while slow-cycling microbes decompose recalcitrant carbon at later stages ( Herzog, 2019 ; Alavoine and Bertrand, 2020 ; Su et al, 2020 ). Thus, by having a greater diversity of microbes there is a greater opportunity for different microbes to perform specific functions associated with the different stages of litter decomposition, nutrient and carbon cycling that together maintain the broad ecosystem functions of plant productivity, diversity, decomposition, and carbon assimilation through time.…”

Root exudates increase soil respiration and alter microbial community structure in alpine permafrost and active layer soils

“…The genus Massilia (Proteobacteria) increased in active layer soils of both aspects. This genus, commonly found in terrestrial cryoenvironments (Rime et al ., 2016b; Adamczyk et al ., 2020; Perez‐Mon et al ., 2020), has been described to consist of mainly copiotrophic bacteria, which might be more competitive than others in using labile substrates for microbial growth (Rime et al ., 2016b; Su et al ., 2020). The phylum Bacteroidetes increased significantly in both active layers NW and SE in response to AREs, particularly the genus Pedobacter in NW soils.…”

Nitrogen addition mediates the effect of soil microbial diversity on microbial carbon use efficiency under long-term tillage practices

“…Moreover, the POC also had a positive effect on MAOC (Fig. 9) because a portion of POC was degraded by microbes and then formed part of the MAOC (Su et al , 2020). Therefore, these results highlight that nitrogen regulates the influence of microbial CUE C:N on soil organic carbon fractions under tillage practices.…”

“…However, some discrepant findings showed that N addition decreased (Ye et al , 2018) or had no significant influence on MAOC (Yuan et al , 2020). The main reason for the inconsistent results could be that microbial residues controlled the changes of soil MAOC pool under N addition and the microbial residues were different due to different N application rates among these studies (Averill & Waring, 2018;Chen et al , 2020a;Su et al , 2020;Yang et al , 2020b).…”