Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization

Introducing legumes into grasslands can enhance soil organic carbon (SOC) storage, but high phosphorus (P) requirement of legume nitrogen (N) fixation may accelerate soil P depletion. As a result, P fertilizers are often applied to improve legume performance. However, the effects of legume introduct...

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Main Authors: Meiqi Guo, Tongtian Guo, Gaowen Yang, Nan Liu, Jiqiong Zhou, Yingjun Zhang
Format: Article
Language:English
Published: Elsevier 2025-04-01
Series:Geoderma
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Online Access:http://www.sciencedirect.com/science/article/pii/S0016706125001004
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author Meiqi Guo
Tongtian Guo
Gaowen Yang
Nan Liu
Jiqiong Zhou
Yingjun Zhang
author_facet Meiqi Guo
Tongtian Guo
Gaowen Yang
Nan Liu
Jiqiong Zhou
Yingjun Zhang
author_sort Meiqi Guo
collection DOAJ
description Introducing legumes into grasslands can enhance soil organic carbon (SOC) storage, but high phosphorus (P) requirement of legume nitrogen (N) fixation may accelerate soil P depletion. As a result, P fertilizers are often applied to improve legume performance. However, the effects of legume introduction and P availability on SOC storage in grasslands remain poorly understood. In this study, we investigated how legume introduction and P fertilization influence SOC physical fractions and associated microbial metabolic activities, based on a ten-year field experiment. Our results showed that legume introduction increased mineral-associated organic carbon (MAOC) by 7.4 % and total SOC by 5.7 % compared to grasslands without legume introduction. This enhancement can be attributed to the improved soil substrate quality (lower carbon to nitrogen ratio) and enhanced microbial carbon (C) limitation (relative microbial nutrient limitation calculated using vector analysis based on ecoenzymatic stoichiometric theory models), which led to higher microbial carbon use efficiency (CUE) and lower microbial metabolic quotient (qCO2). Phosphorus fertilization reduced microbial biomass and qCO2 by increasing microbial C limitation, thereby leading to a 9.3 % increase in particulate organic carbon (POC); however, it did not affect SOC compared to no P fertilization. Moreover, the positive effect of P on POC was observed only when legume was not introduced, indicating legume introduction weakened this positive effect. In conclusion, introducing legumes to natural grasslands can enhance long-term SOC stabilization and storage by stimulating microbial metabolic activity, offering a sustainable strategy to improve soil fertility and agricultural productivity without the need for P fertilization.
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spelling doaj-art-b10c4697890a4d6b9ef6f53636febabd2025-08-20T03:08:35ZengElsevierGeoderma1872-62592025-04-0145611726210.1016/j.geoderma.2025.117262Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilizationMeiqi Guo0Tongtian Guo1Gaowen Yang2Nan Liu3Jiqiong Zhou4Yingjun Zhang5College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China; Key Laboratory of Grassland Management and Rational Utilization, Ministry of Agriculture and Rural Affairs, Beijing 100193, ChinaCollege of Grassland Science and Technology, China Agricultural University, Beijing 100193, China; Key Laboratory of Grassland Management and Rational Utilization, Ministry of Agriculture and Rural Affairs, Beijing 100193, ChinaCollege of Grassland Science and Technology, China Agricultural University, Beijing 100193, China; Key Laboratory of Grassland Management and Rational Utilization, Ministry of Agriculture and Rural Affairs, Beijing 100193, ChinaCollege of Grassland Science and Technology, China Agricultural University, Beijing 100193, China; Key Laboratory of Grassland Management and Rational Utilization, Ministry of Agriculture and Rural Affairs, Beijing 100193, ChinaDepartment of Grassland Science, College of Grassland Science & Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, ChinaCollege of Grassland Science and Technology, China Agricultural University, Beijing 100193, China; Key Laboratory of Grassland Management and Rational Utilization, Ministry of Agriculture and Rural Affairs, Beijing 100193, China; Corresponding author at: College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.Introducing legumes into grasslands can enhance soil organic carbon (SOC) storage, but high phosphorus (P) requirement of legume nitrogen (N) fixation may accelerate soil P depletion. As a result, P fertilizers are often applied to improve legume performance. However, the effects of legume introduction and P availability on SOC storage in grasslands remain poorly understood. In this study, we investigated how legume introduction and P fertilization influence SOC physical fractions and associated microbial metabolic activities, based on a ten-year field experiment. Our results showed that legume introduction increased mineral-associated organic carbon (MAOC) by 7.4 % and total SOC by 5.7 % compared to grasslands without legume introduction. This enhancement can be attributed to the improved soil substrate quality (lower carbon to nitrogen ratio) and enhanced microbial carbon (C) limitation (relative microbial nutrient limitation calculated using vector analysis based on ecoenzymatic stoichiometric theory models), which led to higher microbial carbon use efficiency (CUE) and lower microbial metabolic quotient (qCO2). Phosphorus fertilization reduced microbial biomass and qCO2 by increasing microbial C limitation, thereby leading to a 9.3 % increase in particulate organic carbon (POC); however, it did not affect SOC compared to no P fertilization. Moreover, the positive effect of P on POC was observed only when legume was not introduced, indicating legume introduction weakened this positive effect. In conclusion, introducing legumes to natural grasslands can enhance long-term SOC stabilization and storage by stimulating microbial metabolic activity, offering a sustainable strategy to improve soil fertility and agricultural productivity without the need for P fertilization.http://www.sciencedirect.com/science/article/pii/S0016706125001004Carbon physical fractionsEnzymatic stoichiometryMicrobial community compositionMicrobial metabolic efficiencyMicrobial resource acquisition strategies
spellingShingle Meiqi Guo
Tongtian Guo
Gaowen Yang
Nan Liu
Jiqiong Zhou
Yingjun Zhang
Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
Geoderma
Carbon physical fractions
Enzymatic stoichiometry
Microbial community composition
Microbial metabolic efficiency
Microbial resource acquisition strategies
title Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
title_full Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
title_fullStr Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
title_full_unstemmed Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
title_short Legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
title_sort legume introduction increases soil organic carbon in grassland via regulation of microbial metabolism regardless of phosphorus fertilization
topic Carbon physical fractions
Enzymatic stoichiometry
Microbial community composition
Microbial metabolic efficiency
Microbial resource acquisition strategies
url http://www.sciencedirect.com/science/article/pii/S0016706125001004
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AT gaowenyang legumeintroductionincreasessoilorganiccarboningrasslandviaregulationofmicrobialmetabolismregardlessofphosphorusfertilization
AT nanliu legumeintroductionincreasessoilorganiccarboningrasslandviaregulationofmicrobialmetabolismregardlessofphosphorusfertilization
AT jiqiongzhou legumeintroductionincreasessoilorganiccarboningrasslandviaregulationofmicrobialmetabolismregardlessofphosphorusfertilization
AT yingjunzhang legumeintroductionincreasessoilorganiccarboningrasslandviaregulationofmicrobialmetabolismregardlessofphosphorusfertilization