Exploring community-based adaptive approaches in agriculture and water management to address salinity impacts in coastal Bangladesh

The coastal region of Bangladesh is greatly impacted by high soil and water salinity levels, worsened by tropical cyclones and rising sea levels. Understanding the extent of salinity and its challenges is vital for sustainable agriculture and safe drinking water. This study employed both quantitative methods, focusing on soil and water parameters, as well as qualitative approaches such as focus group discussions (FGDs) and key informant interviews (KIIs). The objectives of this research were to assess soil and water salinity, and soil nutrient content, and to investigate adaptive practices and challenges in agriculture and drinking water management in six sub-districts in the southwestern coastal region of Bangladesh. Qualitative information obtained from 18 FGDs and 16 KIIs was assessed by thematic and content analysis to evaluate the community-based adaptive techniques and challenges in sustainable agriculture and water management in the salinization-affected region. Using a one-way ANOVA and post hoc Tukey tests, the soil and water parameters of the collected 165 soil samples (croplands), and 132 water samples (ponds and canals) were analyzed to assess the soil nutrients (nitrogen, phosphorus, and potassium) and soil and water salinity in six sub-districts.

The soil nitrogen, phosphorus, and potassium contents exhibited significant variations, whereas there was no notable difference in soil salinity content across the studied sub-districts. Upon examination of pond water salinity levels, significant variations were observed among the six sub-districts. The salinity levels (ds cm^-1) in pond water ranged between 13 and 14 ds cm^-1 in these sub-districts. Among them, Shyamnagar recorded the highest level of pond water salinity (13.99), followed by Assasuni (13.96), Dacope (13.91), Koyra (13.58), Morrelganj (13.33), and Mongla (13.19) sub-districts. Pairwise comparisons of salinity levels in pond and canal water show that the salinity level in most water samples varied significantly among sub-districts.

Respondents in FGDs and KIIs consistently identified salinity as a major challenge in agriculture and drinking water in the studied sub-districts. Additionally, climate-induced stresses, such as untimely precipitation, and pest outbreaks during droughts were recognized as significant issues impacting sustainable agriculture. In terms of adaptive practices, this research emphasizes the feasibility of rainwater harvesting as an effective technique for managing drinking water and mitigating water and soil salinity. This approach offers a viable solution for addressing water scarcity and salinity issues in the coastal region. One notable finding in agriculture from the research is the positive impact of organic fertilizer (vermicompost) in reducing soil salinity levels. This finding highlights the potential of utilizing organic fertilizer as a nature-based solution to mitigate salinity in the affected regions of Bangladesh and globally. By adopting such adaptive strategies, the region can promote resilient agricultural systems and ensure sustainable water management.

In summary, the study highlights the prevalence of soil and water salinity in the coastal region of Bangladesh and the associated challenges it poses for agriculture and drinking water management. The research emphasizes the significance of adaptive practices, specifically rainwater harvesting and organic fertilizer, as a practical solution to address water scarcity and salinity issues in the region.