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 establishment of Boro rice crops. The applicability of our findings will vary geographically in the CZ, as a function of prevailing dynamics of river salinity, water tables, soils and climate. To understand the economics at a national scale, our analysis should be extended on a regional basis to estimate regional production gains possible, as well as to assess environmental health risks – particularly related to increased salinization of polder soils. Our analysis suggests that substantial investment in further research and achieving the required social and agronomic changes may be warranted.

盐碱沿海地区（CZ）增加Boro（旱季）水稻产量是孟加拉国政府实现其可持续发展目标（SDG's）战略的一部分。然而，在拉比（干旱）季节，盐碱化和淡水短缺导致CZ地区大片土地仍未被种植和利用不足，作物单产低于潜在水平。我们评估了增加该地区Boro水稻产量和农民利润的一系列选择。这些措施包括改变播种日期，并结合旨在增加灌溉水供应和种植面积的不同田水闸管理策略。我们采用了案例研究的方法，结合了田间试验，APSIM种植系统建模和经济分析，重点是库尔纳分部的Satkhira区。我们发现，最有利可图的策略是在11月中旬（比目前的农民耕作提前一个月左右）在大部分地区使用Bo田运河网络提供的河水灌溉土地上种植Boro水稻。这可以显着提高农民的利润和区域产量（最高4倍）。收益增加的原因是双重的-（1）水稻的潜在单产较高；（2）早期播种释放出大量淡水可利用的潜力，从而大大增加了播种面积，因为那时河盐度水平很低，并且可用的灌溉水数量有限。根据目前的播种日期较晚的做法（大约在12月中旬左右），几乎不使用这些早季水资源。为了获得早播的优势，必须对系统进行某些更改。首先，农民必须在季风季节采用早熟移植的阿曼（T. Aman）水稻品种。其次，他们必须与田水闸管理区的农户同步进行农艺时间安排，以便有效地进行闸门操作，并在十月及时排干田间停滞的季风水，然后早季种植波罗稻米作物。根据河流盐度，地下水位，土壤和气候的主要动态，我们研究结果的适用范围在捷克共和国各地会有所不同。为了了解全国范围内的经济状况，我们的分析应在区域范围内进行扩展，以估计可能的区域生产收益，并评估环境健康风险，尤其是与田土壤盐渍化增加有关的风险。