POST TIME: 17 June, 2019 11:41:50 AM
Effective technology to cope with scarcity of irrigation water
Lifting of underground water must be reduced to the minimum as future of agriculture depends on availability of water amid a formidable threat of climate change when there is alternative to keeping food production rate increasing
Prof. Sarwar Md. Saifullah Khaled

Effective technology to cope with scarcity of irrigation water

Bangladesh is predominantly a lush green agricultural country. It has about 80 percent of its people who are living in the countryside. They are directly or indirectly connected with this primary industry. They need water in the dry season to grow different types of crops in the fields. The Bangladeshi farmers cater the need of not only the rural but also that of the urban people. So agriculture is very important for all classes of people living in both the rural and urban areas of the country. For cultivation the much-needed irrigation process is difficult for the country as rivers and canals are dried up because of the unilateral withdrawal of water by the upstream country. As a result, Bangladesh has to depend on alternative sources of water in the dry season for irrigation as irrigation is a prime necessity for cultivation to grow almost all types of crops that the Bangladeshi farmers usually grow.

But unfortunate enough for us, as has been mentioned above, the country is irrigation water scarce one in the absence of necessary and sufficient surface water for the purpose. In consequence, countrywide the farmers are to depend increasingly on underground water irrigation method. But excessive use of underground water for irrigation purposes has proved ruinous for the ecological balance of the country. Under the circumstances, of late, a new technology termed Adoption of Alternate Drying and Wetting (AWD) irrigation technology to save huge amount of underground water that is used for irrigation purposes has been invented. Minimum 30 percent of irrigation water during Boro rice farming could be saved by substantially reducing pressure on underground water through the AWD irrigation technology. To cope with the scarcity of irrigation water, experts suggested for large-scale adoption of this simplest and effective technology.

The farmers generally use 3,000 to 4,000 litres of irrigated underground water to produce one kilogramme of Boro rice, whereas it needs only 1,500 to 2,000 litres when the AWD irrigation technology is used. The AWD irrigation method determines irrigation times in growing Boro rice in the fields. And it requires only a 7 to 10 centimetres diameter and 25 centimetres long PVC pipe or hollow bamboo pieces or waste bottles of cold drinks for the purpose. Fifteen centimetres on one side of the pipe is perforated for horizontal movement of water. And it is to be installed vertically with its perforated portion under the ground level and the soil within it is to be scooped out to make the soil at the pipe's lower end visible.

The farmers should irrigate Boro fields in such a way that water does not overtop the imperforated portion, watch leaching down of water through the pipe and irrigate when soil at bottom of the pipe is visible with no water standing on soil hat. The horticulture specialists said that in recent years the AWD irrigation technology has been becoming popular among farmers in all the five districts under Rangpur agriculture region. In the year 2018, some 46,216 farmers of the region used the AWD irrigation technology in cultivating Boro rice on their 3,297 hectares of land to increase rice output at lower costs reducing use of irrigation water substantially. Experts are of the opinion that the farmers could largely be benefited by using AWD technology for reduced irrigation frequencies, improved water use efficiency, less use of diesel, electricity and increased rice yield, thus reducing cost of production and saving underground water. Thus the farmers have already started reaping benefits of the AWD technology following its dissemination to them by different agriculture related organizations. Lifting of underground water must be reduced to the minimum as future of agriculture depends on availability of water amid a formidable threat of climate change when there is alternative to keeping food production rate increasing. If the AWD method was adopted for farming Boro rice on 4.8 million hectares of land in the country, 2.4 million tonnes additional paddy worth Taka 64.0 billion would be produced annually along with saving Taka 8.0 billion for less use of diesel and electricity. 

In addition to bringing uncountable benefits, to the farmers in particular and the country in general, the production of 500 kilogrammes of more Boro rice per hectare, the adoption of the simplest and effective AWD technology can reduce 5 numbers of irrigation, save minimum 30 percent underground water, 30 litres diesel and electricity for irrigation. The country’s agriculture sector is facing severe threat due to changing climate. As a result, the experts also favoured for crop zoning to cultivate more irrigation water consuming crops in the southern zones and less water consuming crops in the drought-prone northern zones of the country.

The writer is a retired Professor of Economics, BCS General Education Cadre