Solar-Powered drip Irrigation

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Transforming Agriculture in a Remote Village of the Sundarbans

The Gosaba Island situated in the Sunderbans region of West Bengal in India is surrounded by tidal rivers connected with the Bay of Bengal, bringing water of high salinity (more than 30 dS/m), which is not suitable for irrigation in agriculture. Good- quality groundwater is also unavailable for irrigation due to various technical reasons. Due to these diffi ulties, farmers in this village are unable to grow Rabi crops. Farm ponds, which harvest the rainwater during monsoon, are the only source of water for irrigation in the post-monsoon period.

Success of Solar Powered Drip Irrigation Technology

To increase the cropped area, solar- powered drip irrigation technology has been introduced in the island under the CSI4CZ project. Analysis of monthly weather data available at Canning Town shows that the average bright sunshine hours (BSH) during the Rabi season is 7–9 hours a day, which is sufficient to harness the solar energy for use in agriculture. Under this technology, solar panels were installed near the pond and a nano pump (0.1 hp) was used for lifting after from the farm pond to a tank (1,000 liter capacity) placed at 2.5 m height on a platform. During day time, water is lifted to the tank and the stored water is applied to high-value vegetable crops through drip irrigation system by gravity method. The drip discharge rate was 2.4 litres per hour. The field was divided into different plots, each plot was controlled by a valve, which facilitated crop diversification.

Effectiveness At Ground zero

The solar drip system was installed in the farm of Mr Nitai Hari Mandal in 2017. He cultivated crops, such as cucumber, bitter gourd, and okra during the Kharif season by providing supplemental irrigation during deficit rainfall period. The system effectiveness was enhanced through different mulching materials, such as paddy straw, black plastic, and white plastic, for controlling the weeds and conserving the soil moisture. The yield of vegetables was very promising under black plastic mulching and the crop was free from weed infestation. Since October 2017, he has grown chilli, knol-khol, and okra. Knol-khol and okra were harvested in January 2018. Chili crop continued up to May 2018 which provided regular income to Mr Nitai Hari Mandal as he sold green as well as dry chilies. After the harvest of knol- khol and okra he started growing bitter gourd. Thus, he is able to grow vegetables round the year by this technology. There was 20%–30% more yield; savings of 40%–60% irrigation water; 40% saving of labour, and an increase in the cropping intensity by up to 300% as compared to traditional practices.

The economics of the cultivation under solar drip system (Table 2) for an area of 725 m2 indicated that the system is quite profitable in terms of gross return (`2,5679), net return (`13,876) and output-input ratio (2.2). The profitability of the system can be further increased by increasing the area under operation as well as availing the subsidy from the government schemes.

This initiative was supported by the Australian Centre for International Agricultural Research (ACIAR) and has funded a project, ‘Cropping System Intensification in the Salt-affected Coastal Zones of Bangladesh and West Bengal, India.

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