Effect of Exogenous Nutrient Addition on Soil Organic Carbon Mineralization and Stabilization

Abstract

Soil organic carbon (SOC) pools have the potential to attain sustainable agriculture goals under climate change. External organic and inorganic nutrient inputs considerably affect SOC mineralization and SOC pools. Therefore, a laboratory-based, three-factor soil incubation experiment was conducted to investigate the impact of different exogenous nutrient additions on the mineralization and stability of SOC. The study investigated the effects of three fertilizer types (inorganic, organic, and a combination of inorganic and organic) and three rates of fertilizer addition (low, medium, and high) while considering two temperature levels (15 °C and 25 °C). At 25 °C, the application of fertilizer at a high rate significantly increased the SOC mineralization (2.84–19.97%) compared to fertilizer applied at a low rate, while, at 15 °C, different fertilizer types had no significant impact. Overall, fertilization resulted in an increase in the total potential mineralizable carbon (7.87–84.50%), while the rate of decomposition was decreased. The priming effect of inorganic fertilizer decreased over time, with the main effect observed during the initial 14 days. The addition of organic fertilizer resulted in a lesser increment in the soil activity index while simultaneously yielding a higher Q10 compared to inorganic fertilizer. Overall, the mixed application of organic and inorganic fertilizers was suggested to improve SOC stabilization and promote sustainable agricultural development.