Productivity and economic benefits of integrated nutrient management in three major cropping systems in the mid-hills of Nepal

Combined applications of manure and inorganic fertilizer (integrated nutrient management) may allow sustainable cropping with higher productivity and larger economic benefits than applications of either one alone. This is being examined in three of the major crop rotations in the mid-hills of Nepal. These are rice-wheat on irrigated khet land, millet, either relayed or grown sequentially after maize, on rain-fed bari land, and blackgram grown after upland rice on ancient river terraces, tar land. At each of the six sites seven different nutrient treatments were applied either to a single crop (maize and upland rice) or to both crops (rice and wheat) in the rotation. Manure or inorganic fertilizer, or equal parts of both, were applied at a high rate and at half that rate. A treatment with no additions was also included. Crops of millet and blackgram were unfertilized. Grain yields of maize, upland rice, wheat, and rice were greater at the higher rate of N, as were straw yields. Grain and straw yields were greatest following application of fertilizer alone, except for maize at Pakhribas and wheat at Kholitar, and rice grain yields at Kholitar. For most crops, labor costs exceeded the market value of the yields from the zero-input treatment. Partial budget analysis showed that margins were generally negative when manure was applied either alone or in combination with fertilizer, but positive with applications of fertilizer. Results imply that applications of fertilizer are advantageous in the short-term.