Effects of different land use methods on inert soil carbon
[Objective]Investigating the effects of different land uses on soil inert carbon in grassland is of great significance for objectively understanding the role of grassland in mitigating atmospheric carbon dioxide emissions,de-veloping strategies for carbon sequestration in grassland,and rational utilization of grassland resources.[Method]The total organic carbon and inert carbon of soil at Haibei Alpine Meadow Ecosystem Research Station of the Chi-nese Academy of Sciences were studied under three different land use methods(i.e.,free grazing in winter(winter grazing),grazing exclosure(grazing exclosure),and cultivated annual oats(oats)).[Result]1)Soil organic carbon content in the 0～10 cm soil layer was the highest under winter grazing(95.15 g/kg),followed by grazing exclosure(70.56 g/kg),and cultivated annual oats(54.44 g/kg),The content of soil inert carbon under winter grazing was 27.77%higher than that under grazing exclosure,and 32.54%higher than that under cultivated annual oats.2)Com-pared with winter grazing,soil organic carbon in the 0～10 cm layer decreased by 25.84%after 16 years of grazing ex-closure,and soil organic carbon in the 0～10 cm layer decreased by 42.79%after 30 years of cultivation,Compared to free grazing,the organic carbon in the 0～30 cm soil layer decreased by 10.89%after 16 years of grazing exclosure,and by 9.48%in the 0～30 cm soil layer after 30 years of cultivation,The average inert carbon content in the 0～30 cm soil layer was 22.67%higher under winter grazing than under grazing exclosure,and 3.60%higher under winter grazing than under annual oats,Compared with cultivation,grazing exclosure reduced the inert carbon by 19.78%.3)There was a significant correlation between soil physical and chemical properties and soil carbon pool composition un-der different land use methods,and the change in soil physical and chemical properties was an important reason for the change in soil carbon pool composition under different grassland use methods.[Conclusion]The decrease of soil inert carbon content after grazing prohibition is greater than that after reclamation,and winter grazing is beneficial to the ac-cumulation of soil inert carbon;after prohibition of soil grazing,soil inert carbon content is reduced and the stability of soil organic carbon is weakened,Different land use methods mainly affect soil organic carbon and inert carbon content by affecting soil physical and chemical properties and nutrient content,Therefore,by improving grazing management,the organic carbon storage and the stability of soil organic carbon can be maintained or further increased,and the prohi-bition of grazing in healthy grassland is not conducive to the accumulation of soil organic carbon.
alpine meadowdifferent land use methodssoil organic carboninert carbon
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