Productivity impacts and nutrient balances of an intensive potato-mungbean-rice crop rotation in multiple environments of Bangladesh

Bangladesh needs to produce more food on less land to assure future food security for an increasing population. The two techniques that need to be adopted more frequently are an increase in cropping intensity by producing two or more crops on the same piece of land, and an increase in the productivity of individual crops, particularly their ability to utilize basic or limiting resources such as water and nutrients. In this context, the present study was carried out to assess the most suitable crop rotation based on the dose of organic and inorganic fertilizers as a source of plant nutrients. The potato-mungbean-T. (transplanted) Aman rice (P-M-R) crop rotation was applied to three agro-ecological zones (AEZs) of Bangladesh (Bogra, AEZ-25; Joydebpur, AEZ-28; Jessore, AEZ-11). The results from a two-year experiment indicate that the yield of P-M-R was influenced by the nutrient management applied. Except for potato, higher yield was obtained in the second year. The yield of potato and T. Aman rice was highest when crop residues were incorporated. In all locations, N (nitrogen) and K (potassium) were depleted in both years, but P (phosphorus), S (sulphur), Zn (zinc) and B (boron) showed a positive balance. Even after completing two cropping cycles and incorporating crop residues with different levels of nutrients, there was little change in soil pH, organic matter (%), total N (%), P, K, S, Zn and B. However, in all three locations, organic matter (%), total N (%), P, K, S, Zn and B increased in plots into which crop residues had been incorporated. The soil test-based nutrient management choice that incorporated crop residues gave a higher net return (3506 US$ ha−1) than other nutrient management combinations (3351-3483 US$ ha−1). These results indicate that soil test-based nutrient management and an integrated plant nutrient system that incorporates crop residues are suitable for the potato-mungbean-T. Aman rice crop rotation in multiple environments of Bangladesh.