Nutrient management in calcareous soil improves rice–maize sustainable yield index, performance indicators

Abstract

Rice-maize is an emerging cropping system in South Asia that plays significant role in terms of achieving food security in the region. However, achievement of attainable yield in these two crops is often a constrain due to imbalanced and inadequate use of essential plant nutrients. Understanding the contribution of different nutrients (N, P, K, S and Zn) toward yields of hybrid rice—hybrid maize cropping system in calcareous soil is a need for large number of smallholder farming systems. A four seasons study was conducted with an objective to develop further knowledge on crop productivity and nutrient performance indicators in this newly adapted emerging farming system. Replicated nutrient omission trials were conducted at Bihar, India. At the calcareous soil, omission of the nutrients reduced yields, and N was the most limiting nutrient followed by P and K. Omission of Zn impacted crop yields more than S omission, effect was more prominent in hybrid maize. Nutrient uptake in the cropping system was declined by 58%, 37%, 34%, 31% and 25% for N, P, K, S, and Zn, respectively, when these nutrients were systematically removed from fertilization schedule. Sustainable Yield Index (SYI) for cropping system was highest in the ample balanced fertilizer treatment. Post-harvest soil nutrient availability declined in the nutrient omission plots as compared to the initial soil status. We included additional treatments of ample balanced nutrient application and unfertilized check where hybrid cultivars were replaced by inbred varieties of rice and maize. Cropping system productivity highlighted the synergistic effect of seed and nutrients. The unfertilized checks reduced yield by 9 t/ha and 5 t/ha for the hybrid and inbred cropping systems, respectively. Results from present study conclude that adoption of hybrids in rice-maize system and balanced nutrient management are the best management practices for sustainable food production.