The Water and Salt Balance of Polders / Islands in the Ganges Delta
![](/public/icon/gor.png)
![](/public/icon/pdf.png)
Keywords:
Drainage, Model, Polder salt and water balance, SalinityAbstract
We present a conceptual understanding of the polder salt and water balance processes with a simple model that encapsulates the understanding. The model simulates reasonably well the dynamics of water and salt measured in field experiments at three sites. A feature of both the field measurements and the model is the increase of salinity in the soil and surface water bodies during dry season, despite rainfall exceeding potential evapotranspiration by 0.5 to 1.3 m annually amongst the experimental sites, which should flush salt out of the canals and ponds fairly and quickly. The observed salt in the canals and ponds presumably results from continual re-supply of salt. Capillary rise from a salty groundwater table could supply some salt that would cycle through the soil and into the surface drainage system to the canals and ponds; this behaviour is shown in the model. To remove salt from the polder, canal drainage must be managed effectively. Drainage is also likely to be important at the crop or field level. Irrigation will involve the addition of salt as well as water to the soil surface; the amount will depend on the salt concentration in the water supply. Without adequate field drainage, some of the added salt is likely to be leached downward to the water table in the wet season, only to be brought back again to the surface by capillary rise in the next dry season; over several years, this would lead to high salt concentrations that could limit crop growth. Field drainage should therefore be used in polder cropping systems.Downloads
Downloads
Submitted
Published
Issue
Section
License
Copyright (c) 2019 Indian Society of Coastal Agricultural Research (ISCAR)
![Creative Commons License](http://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png)
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
The copyright of the articles published in the Journal of the Indian Society of Coastal Agricultural Research lies with the Indian Society of Coastal Agricultural Research (ISCAR), who has the right to enter into any agreement with any organization in India or abroad engaged in reprography, photocopying, storage and dissemination of information contained in the journal. However, ISCAR supports open access and there is no restriction in the use, distribution and reproduction in any medium provided that it is not being used for commercial purposes and due credit is given to ISCAR.