Evaluating land use and climate change effects on soil organic carbon. A simulation study in coconut and pineapple systems in west coast India

Abstract

Global climate projections highlight the severe impact of changing rainfall patterns and temperature variations on ecosystems in Asia. This study investigates how land use conversion and climate change affect soil health and carbon storage, emphasizing the need for climate-smart agricultural practices to achieve sustainable production and mitigate climate change. Specifically, we aim to assess the soil organic carbon (SOC) storage potential of different agricultural systems in Southwestern India, including monocultures of pineapple and coconut, a coconut + pineapple intercropping system, and a natural forest as a control. The study evaluated SOC storage across these land use types using field measurements and the RothC simulation model. We also examined the long-term effects of these cropping systems on SOC dynamics under two climate change scenarios: RCP4.5 and RCP8.5. These scenarios differ in projected CO₂ emissions, temperature increases, and rainfall patterns, with RCP8.5 representing a more extreme climate scenario. The results indicate that SOC stock was highest in the natural forest soil (81.1 Mg C/ha) and lowest in the pineapple monoculture (36.7 Mg C/ha), indicating significant SOC loss due to forest conversion to pineapple plantations. Under climate change scenarios, pineapple plantations are predicted to experience a substantial decrease in SOC compared to natural forests, whereas coconut systems maintained steady-state conditions. Notably, the coconut + pineapple intercropping system showed an increasing trend in SOC stocks. Changes in SOC were more pronounced under the RCP4.5 scenario, due to the combined effects of increased temperatures and rainfall in the mid-term (2060 s) and long-term (2080 s). Our findings suggest that integrating coconut land use systems with tree components and pastures can enhance regional carbon budgets and provide a viable strategy for climate change adaptation and mitigation. Promoting such climate-smart agricultural practices will be crucial in maintaining SOC storage and improving soil health under future climate conditions.