Simulating changes in soil carbon stocks for Quercus forests and upland rice fields under climate change scenarios in Manipur (India)

Assessing soil organic carbon (SOC) stocks under different land uses and future climate change (CC) conditions is important to provide better land use planning strategies. In South and Southeast Asia, Quercus forests are widely distributed but are exploited as a source of raw materials and shifting cultivation. Rice is a major staple food grain crop, often cultivated with terracing as upland rice. However, few studies on SOC stocks and simulated SOC dynamics under climate change conditions are available in these regions for these important land uses. Here, we present a case study related to Manipur state in North East region (NER) of India. We used the RothC model to evaluate the short-term changes of SOC stocks in Quercus forests and nearby upland rice fields and the effects of CC on SOC stocks, based on two General Circulation Models (GCMs) and two CO2 Representative Concentration Pathways (RCPs) during three 20-year time periods. Under CC conditions (2019–2078), results differed among land uses, GCMs, RCPs, and time periods, and Quercus forests were more sensitive to climate change than upland rice. For Quercus forests, as average of all GCMs and RCPs, SOC decreased by 0.42 t C ha−1 year−1 in the first time period and by 0.17 t C ha−1 year−1 as sixty years average. In upland rice, SOC decreased by 0.20 t C ha−1 year−1 in the first time period and by 0.12 t C ha−1 year−1 as sixty years average. Results indicated that management strategies for Quercus forests and upland rice are needed for CC mitigation and adaptation particularly in very close CC scenarios.