Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland
Grasslands store 20–30% of global soil organic carbon (SOC) but a majority of grasslands are suffering degradation accompanied by SOC loss. SOC stock is determined by the balance between C input from plants and C output from microbial decomposition, but the relative importance of these factors in co...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-01-01
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| Series: | Ecological Indicators |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1470160X21011729 |
| _version_ | 1819175898986840064 |
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| author | Yuan Yao Junda Chen Fei Li Mingwei Sun Xuechen Yang Gui Wang Jianying Ma Wei Sun |
| author_facet | Yuan Yao Junda Chen Fei Li Mingwei Sun Xuechen Yang Gui Wang Jianying Ma Wei Sun |
| author_sort | Yuan Yao |
| collection | DOAJ |
| description | Grasslands store 20–30% of global soil organic carbon (SOC) but a majority of grasslands are suffering degradation accompanied by SOC loss. SOC stock is determined by the balance between C input from plants and C output from microbial decomposition, but the relative importance of these factors in controlling SOC and the stabilization mechanisms of SOC are poorly understood. Here, we investigated the main factors influencing SOC loss along a grassland degradation gradient in the Horqin grassland, including non-degraded (ND), lightly degraded (LD), moderately degraded (MD), and severely degraded (SD) grasslands. The contents of SOC, TN and TP at the ND and LD sites were significantly higher than those at the MD and SD sites. Plant aboveground, belowground and litter biomass significantly decreased with the intensification of degradation. Compared to the ND site, the mean weight diameter of soil aggregates decreased by 8.70%, 17.39% and 26.1% at the LD, MD and SD sites, respectively. Exchangeable Ca2+ and Mg2+ contents also decreased along the degradation gradient. Moreover, the results of structural equation modeling indicated that grassland degradation reduced plant biomass, resulting in an increase in soil available phosphorus content, thus causing less energy losses for microbes through their deployment of extracellular enzymes, eventually leading to an increase in microbial carbon use efficiency. Correlation analysis also confirmed that microbial carbon use efficiency was positively correlated with the ratio of G+/G-. The results of boosted regression tree model suggested that exchangeable Ca2+ and mean weight diameter were the two most influential factors on SOC among the 13 studied variables. Stabilization mechanisms linked to chemical stabilization by polyvalent cations and soil aggregation were the most important controlling factors on SOC content during grassland degradation. In summary, although microorganisms mitigated soil carbon loss to some extent by decreasing their total biomass and increasing their carbon use efficiency, the weakened physical protection of SOC resulted in SOC loss during grassland degradation. |
| first_indexed | 2024-12-22T21:02:11Z |
| format | Article |
| id | doaj.art-d1757678e7d04b11a593a1ad64fa6b30 |
| institution | Directory Open Access Journal |
| issn | 1470-160X |
| language | English |
| last_indexed | 2024-12-22T21:02:11Z |
| publishDate | 2022-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Ecological Indicators |
| spelling | doaj.art-d1757678e7d04b11a593a1ad64fa6b302022-12-21T18:12:49ZengElsevierEcological Indicators1470-160X2022-01-01134108507Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grasslandYuan Yao0Junda Chen1Fei Li2Mingwei Sun3Xuechen Yang4Gui Wang5Jianying Ma6Wei Sun7Institute 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 130024, China; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, ChinaInstitute 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 130024, ChinaInstitute 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 130024, ChinaInstitute 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 130024, ChinaInstitute 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 130024, China; Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, ChinaInstitute 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 130024, China; College of Life Sciences, Changchun Normal University, Changchun 130032, ChinaKey Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, Jilin 130024, China; Corresponding authors.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 130024, China; Corresponding authors.Grasslands store 20–30% of global soil organic carbon (SOC) but a majority of grasslands are suffering degradation accompanied by SOC loss. SOC stock is determined by the balance between C input from plants and C output from microbial decomposition, but the relative importance of these factors in controlling SOC and the stabilization mechanisms of SOC are poorly understood. Here, we investigated the main factors influencing SOC loss along a grassland degradation gradient in the Horqin grassland, including non-degraded (ND), lightly degraded (LD), moderately degraded (MD), and severely degraded (SD) grasslands. The contents of SOC, TN and TP at the ND and LD sites were significantly higher than those at the MD and SD sites. Plant aboveground, belowground and litter biomass significantly decreased with the intensification of degradation. Compared to the ND site, the mean weight diameter of soil aggregates decreased by 8.70%, 17.39% and 26.1% at the LD, MD and SD sites, respectively. Exchangeable Ca2+ and Mg2+ contents also decreased along the degradation gradient. Moreover, the results of structural equation modeling indicated that grassland degradation reduced plant biomass, resulting in an increase in soil available phosphorus content, thus causing less energy losses for microbes through their deployment of extracellular enzymes, eventually leading to an increase in microbial carbon use efficiency. Correlation analysis also confirmed that microbial carbon use efficiency was positively correlated with the ratio of G+/G-. The results of boosted regression tree model suggested that exchangeable Ca2+ and mean weight diameter were the two most influential factors on SOC among the 13 studied variables. Stabilization mechanisms linked to chemical stabilization by polyvalent cations and soil aggregation were the most important controlling factors on SOC content during grassland degradation. In summary, although microorganisms mitigated soil carbon loss to some extent by decreasing their total biomass and increasing their carbon use efficiency, the weakened physical protection of SOC resulted in SOC loss during grassland degradation.http://www.sciencedirect.com/science/article/pii/S1470160X21011729Grassland degradationSoil aggregateSoil organic carbonMicrobial carbon use efficiencyPolyvalent cations |
| spellingShingle | Yuan Yao Junda Chen Fei Li Mingwei Sun Xuechen Yang Gui Wang Jianying Ma Wei Sun Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland Ecological Indicators Grassland degradation Soil aggregate Soil organic carbon Microbial carbon use efficiency Polyvalent cations |
| title | Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland |
| title_full | Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland |
| title_fullStr | Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland |
| title_full_unstemmed | Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland |
| title_short | Exchangeable Ca2+ content and soil aggregate stability control the soil organic carbon content in degraded Horqin grassland |
| title_sort | exchangeable ca2 content and soil aggregate stability control the soil organic carbon content in degraded horqin grassland |
| topic | Grassland degradation Soil aggregate Soil organic carbon Microbial carbon use efficiency Polyvalent cations |
| url | http://www.sciencedirect.com/science/article/pii/S1470160X21011729 |
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