Options for increasing Boro rice production in the saline coastal zone of Bangladesh

•We evaluated options for increasing Boro rice production at Satkhira, Bangladesh.•Earlier sowing offers higher grain yields with increased cropping area due to better utilisation of fresh river water.•Increases in Boro rice production of up to 4x are possible.•Constraints with late-maturing monsoon rice crops and ineffective sluice gate management must be solved.•Potential problems associated with increased salinization of polder soils need to be investigated. Increasing Boro (irrigated dry season) rice production in the saline coastal zone (CZ) is part of the Bangladesh Government strategy for meeting its Sustainable Development Goals (SDG’s). However salinity and fresh water shortages during the Rabi (dry) season result in large areas of land remaining uncropped and under-utilised in the CZ, with crop yields below potential. We evaluated a range of options for increasing Boro rice production and farmer profit in this region. These included changes to sowing dates in combination with different polder sluice-gate management strategies aimed at increasing irrigation water supply and cropping area. We employed a case-study approach, using a combination of field experimentation, APSIM cropping systems modelling, and economic analysis, focussing on Satkhira District, Khulna Division. We found the most profitable strategies were to establish Boro rice crops in mid-November, around a month earlier than current farmer practice, on larger portions of land irrigated using river water supplied via the polder canal network. This offers significant increases in both farmer profit and regional production (up to 4x). The reasons for the gains are dual – (1) potential rice yields are higher; and (2) early sowing unleashes the potential of extensive fresh-water availability to greatly increase cropping area, because at that time river salinity levels are low and unlimited amounts of suitable irrigation water are available. Under current practices with later sowing dates (around mid-December), these early-season water resources are hardly used. To achieve the advantages of early-sowing, certain system changes are necessary. Firstly, farmers must adopt early-maturing transplanted Aman (T. Aman) rice cultivars in the monsoon season. Secondly, they must synchronise agronomic timings with fellow farmers in polder sluice-gate management zones to allow efficient gate operation and timely drainage of stagnant monsoon waters from fields in October, followed by early-season establ