In sub-Saharan Africa, efforts have been made to increase soil carbon (C) content in agricultural ecosystems, due to severe soil degradation. The use of organic materials is one of the realistic methods to recover soil C. However, the impacts of organic amendments on soil microbial community and C cycles under limited soil C conditions are still unknown. We conducted field experiments using organic amendments in two sites with contrasting C content in Zambia. At both sites, temporal changes of

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... oil carbon dioxide (CO2) emissions, bacterial and archaeal community structures were monitored during crop growing season (126 days). The organic amendments increased CO2 emissions with increased bacterial and archaeal abundance in the Kabwe site, while no impacts were shown in the Lusaka site. We also observed larger temporal variability in soil microbial community structure in Kabwe than in Lusaka. These contrasting results between the two soils might be due to the gap in microbial community stability. However, organic amendments have a significant potential to enhance microbial abundance and consequently sequester soil C in the Kabwe site. Site-specific strategies are needed to deal with the issues of soil C depletion in drylands.