A Chinese study has confirmed the findings of Kenya's Yala Swamp rice farmers, with evidence that cultivating rice and fish together stops disease, ups yields, and cuts the need for both fertilisers and pesticides.
The Yala Swamp farmers, near Lake Victoria, have for decades grown fish and rice in the same flooded paddy fields, and have discovered they never require fertilisers to grow their rice, which is also rarely attacked by common rice diseases such as rice sheath blast - responsible for some 40 per cent of rice losses in the country.
Farmers in other rice growing areas of the world like Bangladesh have been reporting the same impressive results. Now science has found a logical explanation to this. A six-year long study conducted in China found that when fish were introduced into flooded paddy fields, farmers were able to grow the same amount of grain as in conventional rice monocultures, but with more than two-thirds less pesticide and a quarter less fertiliser. Farmers could therefore make large savings on fertilisers and pesticides, which typically represent 60–70 per cent of the total cost of rice production.
Scientists now say the rice-fish technique is good for both the fish and the rice. Safely hidden from birds, the fish thrive in the dense rice plants, while they in turn provide a source of fertiliser with their droppings, eat insect pests and help to circulate oxygen around the rice field. Farmers also claim that keeping fish in rice fields can increase rice yields by up to 10per cent – plus they have the additional supplies of fish.
Tony Odero, a 40-year-old father of two whose father was among the pioneers of the fish rice cultivation, says it began as a result of lack of farming space to rear both the fish and prepare rice paddies, and has since become common place, but no one really questioned why the rice did so well even with little or no fertilizer. “We just thought the gods were good to us, although other crops planted in the farms required lots of fertilizer. We just thought rice in this area was the crop that had been blessed by the gods,” he said.
During planting, Odero build dykes that are around 60cm high on the outskirts of the rice fields, which aids in keeping the fish in the rice fields and enabling vegetable cultivation around the field. He then digs a ditch for the fish to live in during the dry season and plant sthe rice in rows that are roughly 35cm apart, before half-filling of the ditch with water. The water is purified with a small quantity of lime and he also adds a little organic fertiliser. When the rice starts to shoot, the water level across the field is increased to 12–15cm, and small fish or ‘fingerlings’ are released into the ditch. As soon as they have acclimatised to the rice field water, Odero releases them into the field and raises the water level as both the fish and rice grow.
Harvesting happens after 4-5 months. He harvests the rice first, and then drains the rice field to collect the fish into the ditch where they can easily be caught. Odero and fellow farmers report rice yields that are 10 per cent higher and achieve enough fish to provide regular, high-protein meals for their families.
“It hasn't been as easy as it sounds. There were times when the fish would choke, because we didn't know how to tend to them or how to ensure timely harvest so that we can harvest as much as possible in both rice and fish,” he said.
But now the scientific backing of this integrated farming could see it trialled in the predominantly rice growing area of Mwea District in Central Kenya, which has been grappling with perennial rice diseases and spending millions in pesticides. In 2008, half of the rice in Mwea was destroyed by the rice sheath blast. Mwea supplies 80 per cent of Kenyan rice mainly as Basmati and pishori rice. “You can imagine if we would have scaled this fish and rice cultivation, we would have saved the country such a huge loss, but there is no turning back on this one,” said Mwendwa Kitti from the Ministry of Agriculture.