Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
College of Environment and Resources, Zhejiang A & F University, Hangzhou, 311300, China.
Sci Rep. 2020 Mar 26;10(1):5526. doi: 10.1038/s41598-020-62198-2.
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.
归还作物残体是平衡土壤碳（C）损失的一种可行做法。作物残体有机碳向土壤碳的周转率取决于土壤微生物群落动态。然而，作物秸秆输入后土壤微生物群落的任何时间变化与秸秆-C在土壤有机碳（SOC）库中的分布动态之间的关系尚不清楚。本研究使用稳定同位素示踪法研究了秸秆-C在土壤溶解有机碳（DOC）、微生物生物量碳（MBC）、颗粒有机碳（POC）和矿物结合有机碳（MaOC）中的分配，以及使用高通量测序研究了土壤细菌和真菌群落的时间变化。在秸秆分解的前 180 天内，大约 3.93%和 19.82%的秸秆-C分别转化为土壤 MaOC 和 POC，而 0.02%和 2.25%的秸秆-C分别转化为土壤 DOC 和 MBC。土壤微生物群落的时间变化与秸秆-C向 SOC 的分布动态呈正相关（R>0.5，P<0.05）。富养细菌（如链霉菌、马西亚和鞘氨醇单胞菌）、纤维素分解菌和真菌（如 Dyella 和镰刀菌、拟青霉）、嗜酸细菌（如 Edaphobacter 和未分类的 Acidobacteriaceae）、反硝化和固氮微生物（如 Burkholderia-Paraburkholderia、拟青霉和根瘤菌）以及未分类的 Sordariomycetes 真菌与秸秆-C向特定 SOC 分数的分布显著相关（P<0.05），这解释了超过 90%的秸秆-C在土壤中的分配变化。富养、某些纤维素分解和反硝化微生物与秸秆衍生的 DOC 和 MaOC 呈正相关，而其他纤维素分解真菌（如拟青霉）和特定细菌（如根瘤菌）与秸秆衍生的 POC 呈正相关。我们的结果强调了土壤微生物群落结构的时间变化很好地反映了秸秆-C向 SOC 分数的转化和分布过程。
