Ecosystem carbon sequestration of Zanthoxylum bungeanum plantations under the farmland conversion in the arid valley of the upper reaches of Yangtze River, China

Aims Vegetation restoration has been widely implemented to achieve carbon (C) sequestration and prevent land degradation, and this study aims to evaluate the ecosystem C pools and C sequestration effectiveness of different land-use types. Methods In this study, the plant biomass C stock, litter C stock, soil organic C (SOC) stock and ecosystem C sequestration in Zanthoxylum bungeanum plantations (with stand ages of 28, 20, 15 and 8 years, abbreviated as ZB28, ZB20, ZB15 and ZB8, respectively), abandoned land (AL) and farmland (FL) were estimated. Results (1) the plant biomass and biomass C stock of above-and below-ground increased after farmlandconversion, and all of them ranked as ZB28 > ZB20 > ZB15 > AL > ZB8 > FL; (2) the litter stock and C stock, and SOC concentration and stock of different land-use types ranked as AL > Z. bungeanum plantations > FL, and these indices increased with the stand age; (3) the C stock of the ecosystem in FL was 115.4 Mg Cha(- 1), and the C stock of the ecosystem increased by 8.9-66.6 Mg Cha(- 1) and 52.4 Mg Cha(- 1) after the conversion of FL to Z. bungeanum plantations and AL, respectively; (4) and soil C sequestration accounts for 55.6-83.6% of ecosystem C sequestration after farmland conversion. Conclusions This implies that the conversion of farmland to Z. bungeanum plantations was the best approach in the arid valley area when the ecosystem C sequestration and economic benefits were considered.

Automated summary

This study evaluates the ecosystem carbon pools and carbon sequestration effectiveness of different land-use types, and concludes that the conversion of farmland to Zanthoxylum bungeanum plantations is the best approach in the arid valley area when considering ecosystem carbon sequestration and economic benefits.