Different drivers of soil C accumulation in aggregates in response to altered precipitation in a semiarid grassland

Hua Chai; Jie Li; Raúl Ochoa-Hueso; Xuechen Yang; Junqin Li; Bo Meng; Wenzheng Song; Xiaoyue Zhong; Jianying Ma; Wei Sun

doi:10.1016/j.scitotenv.2022.154760

Different drivers of soil C accumulation in aggregates in response to altered precipitation in a semiarid grassland

Sci Total Environ. 2022 Jul 15:830:154760. doi: 10.1016/j.scitotenv.2022.154760. Epub 2022 Mar 24.

Authors

Hua Chai¹, Jie Li², Raúl Ochoa-Hueso³, Xuechen Yang⁴, Junqin Li², Bo Meng⁵, Wenzheng Song⁶, Xiaoyue Zhong², Jianying Ma⁷, Wei Sun⁸

Affiliations

¹ Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, Jilin 130024, China; Center for Ecosystem Sciences and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001, United States of America.
² Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, Jilin 130024, China.
³ Department of Biology, IVAGRO, University of Cádiz, Campus de Excelencia Internacional Agroalimentario (ceiA3), Campus del Rio San Pedro, Puerto Real, Cádiz 11510, Spain.
⁴ Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, Jilin 130024, China; Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, Heilongjiang 150081, China.
⁵ Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, Jilin 130024, China; Institute of Ecology, College of Urban and Environmental Science, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China.
⁶ Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, Jilin 130024, China; Department of Biology, IVAGRO, University of Cádiz, Campus de Excelencia Internacional Agroalimentario (ceiA3), Campus del Rio San Pedro, Puerto Real, Cádiz 11510, Spain.
⁷ Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, Jilin 130024, China.
⁸ Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, Jilin 130024, China. Electronic address: sunwei@nenu.edu.cn.

PMID: 35341864
DOI: 10.1016/j.scitotenv.2022.154760

Abstract

Soil carbon (C) stabilization partially depends on its distribution within soil structural aggregates, and on the physicochemical processes of C within these aggregates. Changes in precipitation can alter the size distribution of aggregate classes within soils, and C input and output processes within these aggregates, which have potential consequences for soil C storage. However, the mechanisms underlying C accumulation within different aggregates under various precipitation regimes remain unclear. In this study, we conducted a 3-year field manipulation experiment to test the effects of a gradient of altered precipitation (-70%, -50%, -30%, 0%, +30%, and +50% amounts compared with ambient rainfall) on soil aggregate distribution and C accumulation in aggregates (53-250 μm, microaggregates; < 53 μm, silt and clay fractions) in a meadow steppe of northeastern China. Our results revealed that the distribution of soil microaggregates decreased along the precipitation gradient, with no detectable discrepant responses with respect to soil C accumulation within the microaggregates to precipitation treatments. In contrast, higher precipitation amounts coupled with a greater proportion of silt and clay fractions enhanced the accumulation of soil C. Importantly, structural equation models revealed that the pathways by which changes in precipitation control the accumulation of soil C varied across aggregate size fractions. Plant biomass was the main direct factor controlling the accumulation of C within soil microaggregates, whereas soil aggregate distribution and enzyme activities strongly interacted with soil C accumulation in the silt and clay fractions. Our findings imply that identifying how plant and soil aggregate properties respond to precipitation changes and drive C accumulation among soil particles will enhance the ability to predict responses of ecosystem processes to future global change.

Keywords: Alteration precipitation; Climate change; Extracellular enzyme activity; Semiarid grassland; Soil aggregate; Soil carbon.

MeSH terms

Carbon / analysis
China
Clay
Ecosystem
Grassland*
Soil* / chemistry

Substances

Soil
Carbon
Clay