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Short and sweet

The Kazibachha River looks like a gift to the rice farmers of Kismat Fultola as it flows past this village 10 kilometres south of the district capital of Khulna, in southwest Bangladesh. Every day, the river swells as the tide pushes in from the Bay of Bengal 100 kilometres away. The water climbs embankments built in the 1960s to 2-3 metres above ground level, permitting gravity irrigation year round. The irony is that the river runs sweet mostly in the rainy season, when fields rarely need irrigation, and turns saline for most of the dry season, when irrigation is essential.

Farmers customarily grow a single rainfed crop of traditional long-duration rice from June to December. In the dry season, 40 per cent of them cultivate a problematic cash crop of sesame, which depends on residual soil moisture and is often spoiled by unpredictable early rain in April or May.

"In 2001, driven by the need for more rice, some farmers in the study area tested growing rice in the dry season," recalls Dr. Manoranjan Mondal of the Irrigation and Water Management Division of the Bangladesh Rice Research Institute. "They transplanted the dry-season rice in February and used river water for irrigation, without anticipating that the water was too saline for rice. This resulted in total crop failure."

The sluice gate through which freshwater was impounded to tide rice fields over between river salinisation and the harvest (Manoranjan Mondal)
The sluice gate through which freshwater was impounded to tide rice fields over between river salinisation and the harvest
Manoranjan Mondal

Early the next year, researchers from the institute and its partners* discussed the failure with farmers and local officials. Twenty-nine farmers agreed to join participatory testing of an innovative cropping system. A three-day training programme instructed farmers how to cultivate modern rice varieties. These would produce a higher-yielding rainy-season crop than traditional varieties, but the crux of the plan was to choose varieties that matured quickly enough for planting twice a year.

Second crop

As they had in the past, participating farmers established seedlings in June and transplanted them in July. By this time, rainfall had leached salinity from the soil, and strong flows of sweet river water meant supplemental irrigation was available when drought made it necessary. The difference was that the new varieties were ready to harvest in October or early November, a month and a half earlier than farmers' traditional varieties. This allowed them to establish a second crop in November, the first month of the dry season, and irrigate it with continued flows of freshwater that entered the 3.5 hectare site at high tide through a one-way flash gate at its northern end.

So far so good. But the river water would turn too saline for rice by mid February, or a month and a half before the dry-season crop matured. The experimenters considered filling the gap with groundwater, which was just fresh enough to use for irrigation at the test site. However, groundwater only half a kilometre away tested 2-3 times more saline. A system that depended on groundwater would thus be a risky venture, all the more so because of the danger that extracting water from the aquifer could draw in saltwater from the river. Instead, the experimenters stocked up on freshwater from the river while it lasted. In the first half of February, they opened the sluice gate at the southern end of the site to fill the sluice canal system. With a low-lift pump, they drew down this supply to irrigate the crop up to the end of March, harvesting in early April.

The result was a doubling or tripling of the annual harvest (factoring in the rice equivalent of the sesame crop) and an improvement of farmers' profit by 50-100 per cent. The system has also reduced soil salinity, halving the spike that occurred during the dry-season fallow. No adverse environmental consequences have been observed, and wild animals benefit from having more freshwater to drink.

Participatory approach

The project's highly participatory approach, including a farmer-run workshop late in the dry season of 2003, has meant quick adoption by farmers in the surrounding area. Carefully nurtured relations with local officials have helped ensure government support for the new cropping system, including a commitment to dredge canals to boost their holding capacity. Mondal and his collaborators have called for more farmer control of canals and sluice gates without compromising the interests of those who live by fishing.

Rice farmers on workshop field day (Manoranjan Mondal)
Rice farmers on workshop field day
Manoranjan Mondal

Meanwhile, they consider how to improve their method of making good the promise of the Kazibachha River. Mondal points out that shortening the cropping turnaround by about two weeks in November would reduce the amount of irrigation water farmers need to impound in February. Another option is to use pumps in February to draw water from the river at low tide, which is acceptably fresh two weeks after the high tide becomes too salty.

"This of course would entail more investment," he says. "A cost-benefit analysis and social acceptance have to be studied carefully."

*International Rice Research Institute (IRRI), Khulna University, Bangladesh Department of Agricultural Extension, and the national NGOs Proshika Manobik Unnayan Kendra and HEED Bangladesh

Date published: May 2005

 

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