APSIM-based insights for enhancing rice productivity and climate change adaptation in the north-eastern hilly regions of India

Rising temperatures and increasing extreme climate events are expected to significantly affect crop yields, including rice production in India. Understanding the responses of different rice genotypes to these climate changes is critical for climate-resilient agriculture. This study assessed the performance of two rice varieties, Shahsarang and Mendri, under varying Soil Organic Carbon (SOC) levels, nutrient management practices and projected climate scenarios. The Shahsarang variety, under baseline conditions, achieved a mean grain yield of 4930 kg/ha in high SOC soils when nursery was sown in early May, while medium and low SOC soils produced 4644 kg/ha and 4212 kg/ha, respectively. By the mid-century (2050), intermediate emission scenarios projected yield reductions of 3 %, 9 % and 12 % for low, medium and high SOC soils, respectively, relative to the respective baselines. In contrast, the Mendri variety demonstrated a yield advantage of 417-1318 kg/ha in high SOC soils under mid- and late-century scenarios. Additionally, following Integrated Nutrient Management (INM) using FYM resulted in increased SOC compared to conventional farmers’ practices. In the present study, C1 (low SOC) soil, the impact of 33-year continuous rice monocropping revealed that applying FYM @ 10 t/ha led to SOC accumulation under 75 % RDN in Shahsarang. While in the Mendri variety, three treatments exhibited positive trends ranging from 0.86 to 2.36 %. However, soils with high carbon content showed limited response to additional inputs. Hence, our study suggests the importance of evaluating genotype-specific responses and soil interactions to develop climate-resilient rice production strategies.