Using competition ratios and total revenue parameters to assess millet and legume intercropping under conservation agriculture production systems in Nepal
Intercropping ratios such as land equivalency ratio (LER), competition ratio (CR), monetary advantage index (MAI) and total revenue from millet+legume intercrop under different conservation agriculture production systems (CAPS) designed for maize-based hill farming system of Nepal were compared using general linear model ANOVA. The data was collected through on-farm experimental plots from 28 farming households in central mid-hill of Nepal for two years. Maize was the only crop in first season (March-June), which was followed by four treatments, i.e. millet sole by conventional tillage (CT), legume sole by CT, millet+legume with CT and millet+legume with strip tillage (ST). Cowpea was planted as legume crop in first year, while was replaced by black gram in second year. The initial trend indicated ST had negative effect on yield of following season maize crop. The average LER of intercropping treatments was significantly higher than the sole crops indicating advantage of intercropping, but strip tillage was found to reduce the derived advantage. Although, LER of millet+legume intercrop increased from 1.16 to 1.31 in ST and 1.27 to 1.39 in CT in second year, total revenue decreased because of reduced contribution of high value legume to total LER. Millet+black gram intercrop in second year was found to have higher LER and monetary advantage index (MAI) than millet+cowpea intercrop in first year. It was found that there is economic incentive to farmers for adopting intercropping but there is no incentive adopt conservation tillage in short term. Considering the long-term sustainability and ecosystem benefits of conservation tillage, farmers need to be provided with initial supports for adoption of conservation agriculture.