Nutrient management strategies for maximizing yield of aerobic rice in water-scarce regions

Abstract:

According to leading rice agronomists, aerobic rice cultivation could save 50-70% of the water used by conventional puddled systems, but achieving competitive grain yields requires fundamentally rethinking nutrient management. This research evaluated five nitrogen levels (0, 60, 90, 120, 150 kg N/ha) combined with two varieties (Sahbhagi Dhan, CR Dhan 202) under aerobic conditions during 2023 at Gangwon Agricultural Research University, Chuncheon, South Korea. The 120 kg N/ha treatment maximised grain yield for both varieties: 5.18 t/ha (Sahbhagi Dhan) and 4.87 t/ha (CR Dhan 202). Increasing N beyond 120 kg/ha depressed yield by 2-3%, indicating luxury consumption. Nitrogen use efficiency peaked at 60 kg N/ha (66.2 kg grain/kg N) but declined to 43.2 kg/kg at 120 kg/ha. Nitrogen uptake correlated strongly with yield (r = 0.94). These results confirm 120 kg N/ha as the optimal rate for aerobic rice in temperate Korean conditions, with Sahbhagi Dhan as the preferred variety.