Increasing cropping intensity through irrigation from shallow tubewells in coastal saline belt of West Bengal

Abstract

The scarcity of good quality water in coastal saline belt in West Bengal is one of the major limitation for growing crops in the rabi/summer season. Despite of excavating many farm ponds covering a considerable area, the stored water in them during the rainy season vanishes within a short duration after the monsoon. This stored surface runoff water is also quantitatively insufficient to meet the irrigation demand for large scale rabi/summer crops. Therefore, the farmers have started exploiting the ground water through shallow tubewells since a few years back. Because of the salinity constraint, somewhere they are suitable for irrigation and somewhere not. The water quality varies from aquifer to aquifer. Five shallow tubewells in Chandkhali village were considered for the study. The shallow tubewell of least depth (240 ft) yielded more saline water than the others having depth 360 to 380 ft. The design details, aquifer positions, their utilization for rabi/summer crop, crop grown and the implications in salinity etc. were studied. The water quality (EC) in the tubewells of more than 350 ft were found suitable for irrigation in the rabi/summer period though the discharge rate generally reduces towards the late summer. As the ground water potential in this region is very high, if the water quality is suitable, then the ground water can be used for increasing the cropping intensity. However, over-exploitation should be avoided to prevent deepening of the water table and saline water intrusion.