Divergent accumulation of microbial and plant necromass along paddy soil development in a millennium scale
Divergent accumulation of microbial and plant necromass along paddy soil development in a millennium scale
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DOI：
10.1016/j.still.2023.105769
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发表时间：
2023-08
影响因子：
6.5
通讯作者：
Yalong Liu;Ping Wang;G. Cai;T. Ge;Jingkuan Wang;G. Guggenberger
中科院分区：
文献类型：
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作者：
Yalong Liu;Ping Wang;G. Cai;T. Ge;Jingkuan Wang;G. Guggenberger
植物输入及其随后的微生物转化驱动土壤有机碳（SOC）的形成和积累。稻田比旱地更有利于有机碳的积累，这主要是因为稻田的厌氧条件占主导地位。然而，在长期水稻栽培下，微生物和植物在SOC积累中的作用还没有在文献中得到很好的探讨。在一个千年尺度的水稻土时序，我们使用氨基糖（AS）和木质素酚（LN）作为示踪剂，调查微生物和植物来源的坏死量的变化，并评估其贡献SOC积累与水稻栽培时间的增加。在1000年的水稻栽培过程中，AS和LN含量随着SOC的积累而增加。土壤pH值和盐分对AS和LN的滞留起着重要的调节作用。与土壤酶活性对LN积累的控制相反（例如，过氧化物酶）、微生物生物量和菌菌比对水稻土AS积累有显著影响。AS和LN的组分也随着时间的推移而变化，在后期表现出半乳糖胺和肉桂基苯酚单元的显著积累。长期的水稻栽培更有利于细菌残留物的积累。在100年内，AS对SOC的贡献大于LN化合物，而LN的贡献最终在后期超过AS。同时，我们发现在较年轻的土壤中氧化木质素降解程度较高，随着水稻种植时间的增加，降解程度降低。前期微生物坏死量的积累大于植物坏死量，后期则相反。研究结果对理解水稻土有机碳的形成和固存过程具有重要意义。
Plant inputs and their subsequent microbial transformations drive the formation and accumulation of soil organic carbon (SOC). Rice paddy is more conducive to SOC accumulation than uplands, primarily because of predominant anaerobic conditions. However, the role of microbes and plants in the buildup of SOC under prolonged rice cultivation has not been well explored in the literature. In a millennium-scale paddy soil chronosequence, we used amino sugars (AS) and lignin phenols (LN) as tracers to investigate microbial and plant-derived necromass changes and evaluated their contributions to SOC accumulation with increasing rice cultivation duration. Across the 1000-year rice cultivation process, AS and LN contents increased with SOC accumulation. Soil pH and salinity are considered to play vital roles in regulating the retention of AS and LN. In contrast to the control of soil enzyme activity on LN accrual (e.g., peroxidase), the microbial biomass and fungi-to-bacteria ratio greatly affected AS accumulation in paddy soil. The components of AS and LN also changed with time, exhibiting a significant accumulation of galactosamine and cinnamyl phenol units in the late stage. Long-term rice cultivation is more conducive to the accumulation of bacterial residues. AS demonstrated a greater contribution to SOC than LN compounds within 100 years, whereas the contribution of LN ultimately exceeded AS in the late stage. Concurrently, we found a higher degree of oxidative lignin degradation in younger soils and reduced degradation with increasing duration of rice paddy cultivation. The accumulation of microbial necromass is more than plant necromass in the early stage, and it is the opposite in the late stage. Our results are critical to understand the formation and sequestration processes of SOC in paddy soils.