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Long-term overgrazing reduces glomalin-related soil protein in alpine grassland
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  • Qian Li,
  • Guangyue Zhao,
  • Dawen Qian,
  • Yangong Du,
  • Xiaowei Guo,
  • Bo Fan,
  • Guangmin Cao
Qian Li
Northwest Institute of Plateau Biology Chinese Academy of Sciences
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Guangyue Zhao
Technology Center, Xining Customs District of China
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Dawen Qian
Northwest Institute of Plateau Biology Chinese Academy of Sciences

Corresponding Author:[email protected]

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Yangong Du
Northwest Institute of Plateau Biology
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Xiaowei Guo
Northwest Institute of Plateau Biology Chinese Academy of Sciences
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Bo Fan
Northwest Institute of Plateau Biology Chinese Academy of Sciences
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Guangmin Cao
Northwest Institute of Plateau Biology Chinese Academy of Sciences
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Abstract

Glomalin-related soil protein (GRSP) is a recalcitrant glycoprotein mainly produced by arbuscular mycorrhizal fungi and contributes to soil carbon sequestration. Human activities (grazing, fertilization, etc.) can change plant productivity, soil carbon pool, and microbial community in an alpine grassland ecosystem. However, no study has reported on the effect of human activities on GRSP. Besides, the effect of the interaction between environmental factors and human activities on GRSP is unknown. This study assessed GRSP response to grazing intensity gradients and fertilization in an alpine grassland (Qinghai-Tibet Plateau). The result showed that livestock grazing changed GRSP stability in alpine grassland. Moreover, the content of total GRSP and easily extractable GRSP were gradually decreased with increasing grazing intensities in both surface and subsurface soils. GRSP was highly positively correlated with soil organic carbon (SOC), total nitrogen (TN), and available phosphorus (AP) but negatively correlated with the soil inorganic carbon (SIC) and PH (P<0.001). GRSP promoted SOC by 3.7-14.18%. In contrast, N and P addition for five years did not affect SOC and GRSP contents. Therefore, GRSP is a stable organic carbon essential for SOC fixation. Short-term distractions cannot affect GRSP stability, while long-term overgrazing can gradually reduce GRSP stability. This study provides new insights into soil carbon pool and ecological stoichiometry in the grassland succession process on the Qinghai-Tibet plateau.