Effect analysis of long-term fertilization on summer corn yield and soil organic carbon in purple soil areas under climate change based on DNDC model

The dynamic changes in soil organic carbon (SOC) storage in farmland are closely related to fertilization strategies and climate change. In order to explore fertilization strategies for increasing yield and sequestering carbon under climate change, this study takes summer corn farmland in purple soil areas as the research object. The DNDC model is calibrated and validated using long-term positioning monitoring experiments, and the calibrated DNDC model is combined with future climate data from CMIP6 model to study the effects of different fertilization measures on summer corn yield and SOC under three future scenarios (baseline scenario, SSP2-4.5 scenario, and SSP5-8.5 scenario). The results shows that in both SSP scenarios, the decrease in rainfall and temperature in the study area showed an upward trend with increasing age, and SSP5-8.5 scenario showed a greater upward trend in rainfall and temperature; The calibrated DNDC model has good simulation performance and can be applied to simulate summer corn yield and SOC in purple soil areas. Under T1 treatment, there was no significant difference in SOC storage under various future scenarios, and climate change had a relatively small impact on the yield and SOC storage of organic fertilizer application; Compared with the baseline scenario, SSP2-4.5 and SSP5-8.5 scenarios can significantly increase the yield of summer corn without fertilization treatment, but significantly reduce the yield of summer corn treated with chemical fertilizer alone; Under CK, T2, and T3 treatments, the SOC reserves of each scenario showed a decreasing trend with age, while under T1 treatment, the organic carbon reserves of each scenario showed an increasing trend with age. By 2100, the SOC reserves of each treatment showed a trend of T1>T3≈T2>CK; Under different fertilization measures, the SOC loss in SSP5-8.5 scenario by 2100 is higher than that in SSP2-4.5 scenario, and high emission scenario will lead to more SOC loss. Research has found that under future climate change, although conventional fertilization methods can ensure stable crop yields, they are not conducive to carbon sequestration in farmland. The combination of organic and chemical fertilizers is a more suitable fertilization management mode for achieving carbon sequestration and yield increase in purple soil farmland.