Water management to address salinity in agriculture in Bangladesh : Research document

Samenvatting

Global food security faces significant challenges due to limited freshwater availability and increasing salinity intrusion. The increasing of water and soil salinity is a complex issue, with expectations that it further increases in the future, negatively impacting food security. The factors that influence these challenges include climate change, population growth, and human activities.
Bangladesh is among the most vulnerable countries due to climate change and development challenges (geographic position, poverty levels and high population density). Effective water management and agricultural practices are important in increasing food security in this context. However climate change together with salinization of the coastal region add to the complexity of ensuring food security. The complexity also lies in that existing salinity is not constant throughout the year. Salinity levels in Bangladesh are dynamic; the levels peak in May/June, just before monsoon rains and increased river discharges and heavy rainfall mitigate them significantly. However, practices such as groundwater over-extraction during the dry season, saline aquaculture, and the reduced inflow of fresh water, increase soil and water salinity in coastal areas.
Local farmers are applying strategies to deal with these saline conditions, using methods such as the raised beds (sarjan system), using salt-tolerant seed varieties, and mulching to limit evapotranspiration and the salinity increase in the root zone. Nevertheless, high salinity levels decrease agricultural yields and reduce arable land availability, particularly in coastal Bangladesh where water scarcity is a primary constraint on farming.
In this region, home to over 139 polders, managing saline water intrusion into these polders is critical. This is achieved through the careful operation of control structures within the polder embankments, a key measure in maintaining agricultural productivity in the face of salinity challenges.
This study elaborates on the Coastal Opportunities and Agriculture Solutions to Tackle Salinity in Bangladesh (COASTS) approach, and provides a reflection on how water management aspects could be addressed when tackling salinity in agriculture, using spatial scale (field to regional) and temporal scale (now to future) to map innovations.