Effects of the reclamation of degraded semi-arid grassland into alfalfa field on soil inorganic carbon
To explore the effects of the reclamation of degraded grassland on soil inorganic carbon(SIC)stocks and identify the mechanisms of SIC accumulation in a semi-arid region of China,we compared the SIC stock in a reclaimed farmland(alfalfa field),with that of an adjacent control site(degraded grassland desert).We used carbon stable isotope measurements to calculate the stock of SIC,pedogenic inorganic carbon(PIC),and lithogenic inorganic carbon(LIC)in 0-300 cm soil profiles at both sites.Our results showed that,in the alfalfa field soil,the total SIC and PIC were enriched by 88.42 and 105.71 Mg·hm-2,respectively,while the total LIC stock was depleted by 17.29 Mg·hm-2 compared with the degraded grassland.The reclamation of the degraded grassland promoted the accumulation of SIC,which was mainly caused by the accumulation of PIC in deep soil.Our findings indicate that,in semi-arid areas,reclamation can enhance the soil's carbon sequestration capacity,and that the net accumulation of SIC is mainly driven by the increase in PIC.
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