Alternative cropping and feeding options to enhance sustainability of mixed crop-livestock farms in Bangladesh

We investigated alternative cropping and feeding options for large (>10 cows), medium (5-10 cows) and small (<= 4 cows) mixed crop - livestock farm types, to enhance economic and environmental performance in Jhenaidha and Meherpur districts - locations with increasing dairy production - in south western Bangladesh. Following focus group discussions with farmers on constraints and opportunities, we collected baseline data from one representative farm from each farm size class per district (six in total) to parameterize the whole-farm model FarmDESIGN. The six modelled farms were subjected to Pareto-based multi-objective (differential evolution algorithm) optimization to generate alternative dairy farm and fodder configurations. The objectives were to maximize farm profit, soil organic matter balance, and feed self-reliance, in addition to minimizing feed costs and soil nitrogen losses as indicators of sustainability. The cropped areas of the six baseline farms ranged from 0.6 to 4.0 ha and milk production per cow was between 1,640 and 3,560 kg year(-1). Feed self-reliance was low (17%-57%) and soil N losses were high (74-342 kg ha(-1) year(-1)). Subsequent trade-off analysis showed that increasing profit and soil organic matter balance was associated with higher risks of N losses. However, we found opportunities to improve economic and environmental performance simultaneously. Feed self-reliance could be increased by intensifying cropping and substituting fallow periods with appropriate fodder crops. For the farm type with the largest opportunity space and room to manoeuvre, we identified four strategies. Three strategies could be economically and environmentally benign, showing different opportunities for farm development with locally available resources.