Impact of climate change and management strategies on water and salt balance of the polders and islands in the Ganges delta

Abstract

Enhancing crop production, particularly by growing a crop in the typically-fallow dry season is a key strategy for alleviating poverty in the Ganges delta region. We used a polder water and salt balance model to examine the impact of several crop management, salt management and climate change scenarios on salinity and crop evapotranspiration at Dacope and Amtali in Bangladesh and Gosaba in India. A key (and unsurprising) finding is that salt management is very important, particularly at the two drier sites, Dacope and Gosaba. Good salt management lowers salinity in the shallow groundwater, soil and water storage ponds, and leads to more irrigation. Climate change is projected to alter rainfall, and this in turn leads to modelled increases or decreases in runoff from the polders, and thence affect salt concentrations in the soil and ponds and canals. Thus, the main impacts of climate change are through the indirect impacts on salt concentrations, rather than the direct impacts of the amount of water supplied as rainfall. Management practices to remove salt from polders are therefore likely to be effective in combatting the impacts of projected climate change particularly at Dacope and Gosaba.

CeO2 Nanoparticles Seed Priming Increases Salicylic Acid Level and ROS Scavenging Ability to Improve Rapeseed Salt Tolerance

“…[ 1 ] Due to factors such as poor irrigation management, human activities, and climate change, the trend of soil salinization is increasing. [ 2 , 3 ] Plants are known to respond to salt stress in two phases: 1) high salinity induced osmotic stress, and 2) the over‐accumulation of ions such as sodium and chloride caused ionic toxicity. [ 4 , 5 ] Besides osmotic stress and ion toxicity of salinity on plants, the accumulation of reactive oxygen species (ROS) such as superoxide ( • O 2 − ), hydrogen peroxide (H 2 O 2 ), hydroxyl radical (OH • ), and singlet oxygen ( 1 O 2 ) could lead to oxidative stress.…”

Cropping system intensification for smallholder farmers in coastal zone of West Bengal, India: A socio-economic evaluation

“…cultivated but most of the land in rabi (winter/dry) season remained fallow due to a shortage of good quality irrigation water and therefore targeted by the policy planners to achieve higher cropping system intensification (Aravindakshan et al, 2018;Mainuddin et al, 2019;Yadav et al, 2020). Therefore, enhancing crop production, particularly by growing a crop in the typically-fallow dry season is a key strategy that has a direct positive impact on alleviating poverty in the Ganges delta region (Mainuddin et al, 2021b), and productivity in the coastal zone can be increased by several folds (Bhattacharya et al, 2015;Ritu et al, 2015;Saha et al, 2015). Key challenges for achieving higher cropping intensifications are: excess water in kharif season causing a waterlogged situation; availability of less water (good quality) during rabi season (dry) resulting in salinity building up on the soil surface that limits the number of choices of crops (Mandal et al, 2011a;Humphreys et al, 2015); the trade-off between off-farm and on-farm income often becomes unfavorable to agriculture due to low return; in coastal saline conditions, particularly in rabi season cropping becomes more risky and uncertain that leads to large areas under fallow land.…”

Growth and yield responses of sunflower to drainage in waterlogged saline soil are caused by changes in plant-water relations and ion concentrations in leaves

“…The coastal zone of the Ganges Delta covers more than 30% of the total cultivable lands of Bangladesh, and around 40% of this area is affected by various degrees of soil salinity (SRDI 2010). This zone is also subject to waterlogging following heavy rainfall in the monsoon (aman) season, river flooding and the development of a shallow water-table (Mainuddin et al 2021). In the dry (rabi season) crops can be subject to a wide range of climate risks.…”