Problem and prospects of micro-irrigation in coastal salt affected soils of West Bengal

Abstract

The coastal lands in West Bengal are flat with little or no slope and often suffer from inadequate drainage and waterlogging during the rainy season; and water scarcity and salinity in the post monsoon period. Number of experiments were carried out at ICAR-CSSRI, RRS, Canning Town farm in the years 2001-04 and 2012-15 utilizing the modern irrigation techniques such as micro-sprinkler and drip irrigation systems using electric, gravity and solar power. These systems were used during the post monsoon period for conducting experiments on vegetable crops. Irrigations were scheduled based on cumulative pan evaporation data. Measurements were made to evaluate the salinity in the root zone and crop performance in terms of yield and return. In the gravity drip irrigation system, four crops such as okra, red beet, basella and cow pea were taken for the experimentation. Cow pea suffered most and okra crop performed best among the vegetables if there is flash flood in the field. The wind which occurs frequently in the non-monsoon period affects the uniformity of water application in micro-sprinkler irrigation and cause more evaporation loss. Among the seven types of crops such as Tomato, Beet, Knol-khol, Cabbage, Cauliflower, Chilli and Okra, the return was highest in tomato crop in comparison to cabbage, cauliflower, red beet, knoll-khol, and chilli during the rabi season having good market price and regular market demand. The soil salinity in the rootzone was less than 3 dS/m at the staring of the season. Later the soil salinity decreased due to the drip irrigation and increased at the non-irrigated soil at the upper depths. In the solar drip irrigation system experiment, the solar energy was amply available in the rabi/summer season and there was 60 % saving of labour and 40 to 50 % saving of water in comparison to traditional manual irrigation with 20 to 30 percent increase in yield.The productivity of coastal lands can be improved by efficiently utilizing the limited available water.