摘要
To explore the optimal land-use for soil carbon （C） sequestration in Inner Mongolian grasslands, we investigated C and nitrogen （N） storage in soil and soil fractions in 8 floristi- cally and topographically similar sites which subjected to different lancl-use types （free-grazing, grazing exclusion, mowing, winter grazing, and reclamation）. Compared with free-grazing grasslands, C and N storage in the 0-50 cm layer increased by 18.3% （15.5 Mg C ha-1） and 9.3% （0.8 Mg N ha-1） after 10-yr of grazing exclusion, respectively, and 21.9% （18.5 Mg C ha-1） and 11.5% （0.9 Mg N ha-1） after 30-yr grazing exclusion, respectively. Similarly, soil C and N storage increased by 15.3% （12.9 Mg C ha-1） and 10.2% （0.8 Mg N ha-1） after 10-yr mowing, respectively, and 19.2% （16.2 Mg C ha-1） and 7.1% （0.6 Mg N ha-1） after 26-yr mowing, respectively. In contrast, soil C and N storage declined by 10.6% （9.0 Mg C ha-1） and 11.4% （0.9 Mg N ha-1） after 49-yr reclamation, respectively. Moreover, increases in C and N storage mainly occurred in sand and silt fractions in the 0-10 cm soil layer with grazing exclusion and mowing. Our findings provided evidence that Inner Mongolian grassslands have the capacity to sequester C and N in soil with improved management practices, which were in the order： grazing exclusion 〉 mowing 〉 winter grazing 〉 reclamation.
To explore the optimal land-use for soil carbon （C） sequestration in Inner Mongolian grasslands, we investigated C and nitrogen （N） storage in soil and soil fractions in 8 floristi- cally and topographically similar sites which subjected to different lancl-use types （free-grazing, grazing exclusion, mowing, winter grazing, and reclamation）. Compared with free-grazing grasslands, C and N storage in the 0-50 cm layer increased by 18.3% （15.5 Mg C ha-1） and 9.3% （0.8 Mg N ha-1） after 10-yr of grazing exclusion, respectively, and 21.9% （18.5 Mg C ha-1） and 11.5% （0.9 Mg N ha-1） after 30-yr grazing exclusion, respectively. Similarly, soil C and N storage increased by 15.3% （12.9 Mg C ha-1） and 10.2% （0.8 Mg N ha-1） after 10-yr mowing, respectively, and 19.2% （16.2 Mg C ha-1） and 7.1% （0.6 Mg N ha-1） after 26-yr mowing, respectively. In contrast, soil C and N storage declined by 10.6% （9.0 Mg C ha-1） and 11.4% （0.9 Mg N ha-1） after 49-yr reclamation, respectively. Moreover, increases in C and N storage mainly occurred in sand and silt fractions in the 0-10 cm soil layer with grazing exclusion and mowing. Our findings provided evidence that Inner Mongolian grassslands have the capacity to sequester C and N in soil with improved management practices, which were in the order： grazing exclusion 〉 mowing 〉 winter grazing 〉 reclamation.
基金
National Natural Science Foundation of China, No31070431
No.40803024
Strategic Priority Research Program--Climate Change： Carbon Budget and Related Issues of the Chinese Academy of Sciences, No.XDA05050602
