Soilicrobivorous nematodes contribute to the formation of microbial necromass carbon under full straw return

IF 6.4 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment Pub Date : 2025-09-12 DOI:10.1016/j.agee.2025.109975

Jigao Wang , Kai Wei , Yanli Jing , Yanling Wang , Jinlong Yan , Tao Wang , Jialiang Tang , Bo Zhu

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引用次数: 0

Abstract

Soil microbivorous nematodes (bacterivores and fungivores) regulate the formation of microbial necromass carbon (MNC) through predation-driven shifts in microbial biomass and community composition, with straw return amplifying these effects via an increase in the abundance of microbivorous nematodes. However, how microbivorous nematodes affect MNC formation under straw return remains unclear. A 14-year field experiment was conducted in Southwest China to investigate the soil microbivorous nematode abundance, microbial biomass, and MNC content, along with their relationships across four levels of straw return: control (0 % return, CK), low (30 % return, S30), moderate (50 %, S50), and full (100 %, S100). Compared to the CK treatment, all straw return treatments significantly increased the contents of bacterial necromass carbon (BNC) by 29.1–55.3 %, fungal necromass carbon (FNC) by 35.5–49.8 %, and MNC by 33.4–51.6 %, but compared to the CK treatment, only the S100 treatment significantly increased the proportions of BNC, FNC, and MNC contributing to soil organic carbon (SOC). Compared to the CK treatment, the S100 treatment also significantly increased the abundance of r-strategist bacterivores by 163.4 %, bacterial biomass by 21.7 %, and the ratio of gram-positive (G+) bacteria to gram-negative (G-) bacteria by 9.3 %. Further correlation and aggregated boosted trees (ABT) analyses indicated that r-strategy bacterivores promoted BNC formation by influencing bacterial biomass and the ratio of G+ to G-. Moreover, the carbon use efficiency (CUE) of bacterivores was significantly positively correlated with the BNC and the ratios of BNC and MNC to SOC. Compared to the S30 and S50 treatments, the S100 treatment significantly increased the content of BNC, which was attributed to the elevated CUE of bacterivores in the S100 soil. Additionally, although straw return also significantly increased the abundance of fungivores, ABT analysis indicated that the effect of bacterivores on FNC was stronger than that of fungivores. Overall, 14 years of continuous straw return in a maize-wheat rotation system can increase the MNC content and its ratio to SOC by influencing the abundance of microbivorous nematodes and CUE, with the most pronounced effects observed under the S100 treatment.

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土壤食性线虫在全秸秆还田条件下促进微生物坏死团碳的形成

土壤微生物线虫（食菌和食真菌）通过捕食驱动微生物生物量和群落组成的变化来调节微生物坏死物碳（MNC）的形成，秸秆还林通过增加微生物线虫的丰度放大了这些影响。然而，在秸秆还田条件下，食微生物线虫如何影响MNC的形成仍不清楚。在中国西南地区进行了为期14年的田间试验，研究了土壤微生物食性线虫丰度、微生物生物量和MNC含量，以及秸秆还田4个水平(对照（0 %还田，CK）、低还田（30 %还田，S30）、中还田（50 %,S50）和全还田（100 %,S100）之间的关系。与CK处理相比，所有秸秆还田处理均显著提高了细菌坏死块碳（BNC）含量29.1 ~ 55.3% %，真菌坏死块碳（FNC）含量35.5% ~ 49.8% %，MNC含量33.4 ~ 51.6 %，但与CK处理相比，只有S100处理显著提高了BNC、FNC和MNC对土壤有机碳（SOC）的贡献比例。与CK处理相比，S100处理也显著提高了r-战略细菌的丰度163.4 %，细菌生物量21.7 %，革兰氏阳性（G+）细菌与革兰氏阴性（G-）细菌的比例9.3 %。进一步的相关分析和聚合增强树（ABT）分析表明，r策略的细菌捕食者通过影响细菌生物量和G+ 与G-的比例来促进BNC的形成。此外，细菌捕食者的碳利用效率（CUE）与BNC、BNC和MNC与SOC的比值呈显著正相关。与S30和S50处理相比，S100处理显著提高了土壤BNC含量，这是由于S100处理提高了土壤中细菌的CUE含量。此外，尽管秸秆还田也显著增加了食真菌动物的丰度，但ABT分析表明，食细菌动物对FNC的影响强于食真菌动物。总体而言，连续14年秸秆还田可以通过影响食微生物线虫和CUE的丰度来提高MNC含量及其与土壤有机碳之比，其中以S100处理效果最为显著。

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来源期刊

Agriculture, Ecosystems & Environment 环境科学-环境科学

CiteScore

11.70

自引率

9.10%

发文量

392

审稿时长

26 days

期刊介绍： Agriculture, Ecosystems and Environment publishes scientific articles dealing with the interface between agroecosystems and the natural environment, specifically how agriculture influences the environment and how changes in that environment impact agroecosystems. Preference is given to papers from experimental and observational research at the field, system or landscape level, from studies that enhance our understanding of processes using data-based biophysical modelling, and papers that bridge scientific disciplines and integrate knowledge. All papers should be placed in an international or wide comparative context.