Fungal and bacterial necromass: Opposite drivers of mineral-associated organic carbon gains and losses

IF 6.1 1区农林科学 Q1 SOIL SCIENCE

Soil & Tillage Research Pub Date : 2025-05-12 DOI:10.1016/j.still.2025.106634

Zihuan Fu , Yuxuan Zhang , Weiwen Qiu , Waqas Mohy-Ud-Din , Zhifeng Yan , Yakov Kuzyakov

{"title":"Fungal and bacterial necromass: Opposite drivers of mineral-associated organic carbon gains and losses","authors":"Zihuan Fu , Yuxuan Zhang , Weiwen Qiu , Waqas Mohy-Ud-Din , Zhifeng Yan , Yakov Kuzyakov","doi":"10.1016/j.still.2025.106634","DOIUrl":null,"url":null,"abstract":"<div><div>Microbial necromass is a major contributor to mineral-associated organic carbon (MAOC), widely recognized as the primary and stable carbon (C) pool in soils. Nevertheless, long-term land use changes modify MAOC content and composition, including its fungal and bacterial contributions, which depend on soil types, particularly its hydraulic properties. Here, the impacts of over 30 years of land use, encompassing dryland pasture (DryPast), irrigated-pasture (IrrPast) and cropland (IrrCrop), on MAOC were evaluated across three representative soils with varying drainage characteristics: well-drained Lismore soil (LIS), moderately drained Templeton soil (TEM), and poorly drained Waterton/Temuka soil (WAT). Soil organic carbon (SOC) content and MAOC content decreased in order of IrrPast > DryPast > IrrCrop. MAOC determined the total SOC gains and losses after DryPast conversion to IrrPast and IrrCrop, respectively. Land use change had varying impacts on MAOC, which were influenced by the specific soil types. The well-drained LIS soil showed the highest MAOC increase, rising by 26 % following the conversion from DryPast to IrrPast. In contrast, the poorly drained WAT soil experienced the most significant MAOC reduction, decreasing by 22 % after the conversion to IrrCrop. Fungal necromass dominated MAOC gains, while bacterial necromass drove MAOC losses. Furthermore, the response of MAOC to land uses was primarily affected by labile C as the major source of microbial activity and binding agents. The stabilized fungal necromass is primarily protected within micropores of 0.2–3 µm. In contrast, bacterial necromass is largely constrained by the availability of labile nitrogen. Overall, the increase in fungal necromass and the decrease in bacterial necromass, driven by the interplay between specific management (e.g., irrigation or cultivation) and soil type (e.g., hydraulic properties), are important to interpret MAOC responses to changes in land use.</div></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":"253 ","pages":"Article 106634"},"PeriodicalIF":6.1000,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Soil & Tillage Research","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0167198725001886","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"SOIL SCIENCE","Score":null,"Total":0}

引用次数: 0

Abstract

Microbial necromass is a major contributor to mineral-associated organic carbon (MAOC), widely recognized as the primary and stable carbon (C) pool in soils. Nevertheless, long-term land use changes modify MAOC content and composition, including its fungal and bacterial contributions, which depend on soil types, particularly its hydraulic properties. Here, the impacts of over 30 years of land use, encompassing dryland pasture (DryPast), irrigated-pasture (IrrPast) and cropland (IrrCrop), on MAOC were evaluated across three representative soils with varying drainage characteristics: well-drained Lismore soil (LIS), moderately drained Templeton soil (TEM), and poorly drained Waterton/Temuka soil (WAT). Soil organic carbon (SOC) content and MAOC content decreased in order of IrrPast > DryPast > IrrCrop. MAOC determined the total SOC gains and losses after DryPast conversion to IrrPast and IrrCrop, respectively. Land use change had varying impacts on MAOC, which were influenced by the specific soil types. The well-drained LIS soil showed the highest MAOC increase, rising by 26 % following the conversion from DryPast to IrrPast. In contrast, the poorly drained WAT soil experienced the most significant MAOC reduction, decreasing by 22 % after the conversion to IrrCrop. Fungal necromass dominated MAOC gains, while bacterial necromass drove MAOC losses. Furthermore, the response of MAOC to land uses was primarily affected by labile C as the major source of microbial activity and binding agents. The stabilized fungal necromass is primarily protected within micropores of 0.2–3 µm. In contrast, bacterial necromass is largely constrained by the availability of labile nitrogen. Overall, the increase in fungal necromass and the decrease in bacterial necromass, driven by the interplay between specific management (e.g., irrigation or cultivation) and soil type (e.g., hydraulic properties), are important to interpret MAOC responses to changes in land use.

查看原文本刊更多论文

真菌和细菌坏死块：矿物相关有机碳收益和损失的相反驱动因素

微生物坏死团块是矿物伴生有机碳（MAOC）的主要贡献者，被广泛认为是土壤中主要和稳定的碳库。然而，长期的土地利用变化会改变MAOC的含量和组成，包括其真菌和细菌的贡献，这取决于土壤类型，特别是其水力特性。在这里，30多年的土地利用，包括旱地牧场（DryPast），灌溉牧场（IrrPast）和农田（IrrCrop），对MAOC的影响进行了评估，包括3种具有不同排水特征的代表性土壤：排水良好的Lismore土壤（LIS），中等排水的Templeton土壤（TEM）和排水差的Waterton/Temuka土壤（WAT）。土壤有机碳（SOC）含量和MAOC含量依次为IrrPast >； DryPast >； IrrCrop。MAOC分别测定了DryPast转化为IrrPast和IrrCrop后的总SOC增益和损失。土地利用变化对MAOC有不同程度的影响，受土壤类型的影响。排水良好的LIS土壤的MAOC增幅最大，从DryPast转化为IrrPast后，MAOC增幅为26% %。相比之下，排水不良的WAT土壤的MAOC减少最为显著，转换为IrrCrop后减少了22% %。真菌坏死团主导了MAOC的增加，而细菌坏死团则导致了MAOC的损失。此外，土壤中微生物活性和结合剂的主要来源是活性碳，这主要影响了MAOC对土地利用的响应。稳定的真菌坏死块主要被保护在0.2-3 µm的微孔内。相反，细菌坏死团很大程度上受不稳定氮的可用性的限制。总体而言，真菌坏死块的增加和细菌坏死块的减少是由特定管理（如灌溉或耕作）和土壤类型（如水力性质）之间的相互作用驱动的，这对于解释MAOC对土地利用变化的响应是重要的。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Soil & Tillage Research 农林科学-土壤科学

CiteScore

13.00

自引率

6.20%

发文量

266

审稿时长

5 months

期刊介绍： Soil & Tillage Research examines the physical, chemical and biological changes in the soil caused by tillage and field traffic. Manuscripts will be considered on aspects of soil science, physics, technology, mechanization and applied engineering for a sustainable balance among productivity, environmental quality and profitability. The following are examples of suitable topics within the scope of the journal of Soil and Tillage Research: The agricultural and biosystems engineering associated with tillage (including no-tillage, reduced-tillage and direct drilling), irrigation and drainage, crops and crop rotations, fertilization, rehabilitation of mine spoils and processes used to modify soils. Soil change effects on establishment and yield of crops, growth of plants and roots, structure and erosion of soil, cycling of carbon and nutrients, greenhouse gas emissions, leaching, runoff and other processes that affect environmental quality. Characterization or modeling of tillage and field traffic responses, soil, climate, or topographic effects, soil deformation processes, tillage tools, traction devices, energy requirements, economics, surface and subsurface water quality effects, tillage effects on weed, pest and disease control, and their interactions.