Divergent contribution of particulate and mineral-associated organic matter to soil carbon in grassland

Jiaojiao Liao; Xuan Yang; Yanxing Dou; Baorong Wang; Zhijing Xue; Hui Sun; Yang Yang; Shaoshan An

doi:10.1016/j.jenvman.2023.118536

Divergent contribution of particulate and mineral-associated organic matter to soil carbon in grassland

J Environ Manage. 2023 Oct 15:344:118536. doi: 10.1016/j.jenvman.2023.118536. Epub 2023 Jun 29.

Authors

Jiaojiao Liao¹, Xuan Yang², Yanxing Dou³, Baorong Wang⁴, Zhijing Xue⁵, Hui Sun⁶, Yang Yang⁷, Shaoshan An⁸

Affiliations

¹ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Ministry of Water Resources, CAS, Yangling, 712100, China; College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China. Electronic address: Jiaojiao_liao@163.com.
² College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China. Electronic address: 447676624@qq.com.
³ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Ministry of Water Resources, CAS, Yangling, 712100, China. Electronic address: douyanxing@nwafu.edu.cn.
⁴ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Ministry of Water Resources, CAS, Yangling, 712100, China. Electronic address: wangbaorong92@163.com.
⁵ College of Geography and Tourism, Shaanxi Normal University, Xi 'an, 710119, China. Electronic address: xue1986@snnu.edu.cn.
⁶ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; National Observation and Research Station of Earth Critical Zone on the Loess Plateau, Xi'an, Shaanxi, 710061, China. Electronic address: sunhuisxau@qq.com.
⁷ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Ministry of Water Resources, CAS, Yangling, 712100, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; National Observation and Research Station of Earth Critical Zone on the Loess Plateau, Xi'an, Shaanxi, 710061, China. Electronic address: yangyang@ieecas.cn.
⁸ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Ministry of Water Resources, CAS, Yangling, 712100, China; College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China. Electronic address: shan@ms.iswc.ac.cn.

PMID: 37392693
DOI: 10.1016/j.jenvman.2023.118536

Abstract

Sequestration of soil organic carbon (SOC) is an effective means to draw atmospheric CO₂. Grassland restoration is one of the fastest methods to increase soil C stocks, and particulate-associated C and mineral-associated C play critical roles in soil C stocks during restoration. Herein, we developed a conceptual mechanistic frame regarding the contributions made by mineral-associated organic matter to soil C during the restoration of temperate grasslands. Compared to 1-year grassland restoration, 30-year restoration increased mineral-associated organic C (MAOC) by 41% and particulate organic C (POC) by 47%. The SOC changed from microbial MAOC predominance to plant-derived POC predominance, as the POC was more sensitive to grassland restoration. The POC increased with plant biomass (mainly litter and root biomass), while the increase in MAOC was mainly caused by the combined effects of increasing microbial necromass and leaching of the base cations (Ca-bound C). Plant biomass accounted for 75% of the increase in POC, whereas bacterial and fungal necromass contributed to 58% of the variance in MAOC. POC and MAOC contributed to 54% and 46% of the increase in SOC, respectively. Consequently, the accumulation of the fast (POC) and slow (MAOC) pools of organic matter are important for the sequestration of SOC during grassland restoration. Overall, simultaneous tracing of POC and MAOC helps further understand the mechanisms and predict soil C dynamics combined with the input of plant C, microbial properties, and availability of soil nutrients during grassland restoration.

Keywords: Carbon input; Grassland; Microbial biomass; Mineral-associated organic C; Particulate organic C.

MeSH terms

Biomass
Carbon Sequestration
Carbon*
Dust
Grassland
Minerals
Soil Microbiology
Soil*

Substances

Carbon
Soil
Dust
Minerals