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Economy

Farmers adopt new method to grow more rice with less water

A farmer prepares land to grow rice through the paddy system in Nyando District. This method requires continuous flooding unlike the SRI, which only needs sufficiently moist soils or alternate wetting and drying, sharply reducing water use. JACOB OWITI
A farmer prepares land to grow rice through the paddy system in Nyando District. This method requires continuous flooding unlike the SRI, which only needs sufficiently moist soils or alternate wetting and drying, sharply reducing water use. JACOB OWITI 

Kenyan rice farmers are switching to a new technology that is set to double production and help bridge supply deficit for the country’s domestic consumption.

More than 1,800 farmers have adopted the system which improves yields, grain quality, size and aroma, and uses up to 50 per cent less water than the conventional system.

The System for Rice Intensification (SRI) developed by the Jomo Kenyatta University of Agriculture and Technology is expected to improve production by more than 50 per cent while saving on increasingly scarce water.

Rice consumption in Kenya is estimated at 300,000 metric tonnes compared to a consumption of 45,000 to 80,000 metric tonnes. The deficit is met by imports mainly from Asia which were valued at Sh7 billion by 2008.

Consumption rate

The country’s consumption rate is increasing at a rate of 12 per cent annually compared to four per cent for wheat and maize (one per cent)

“Rice is becoming quite an important crop due to urbanisation and changing trends,” said Ms Esther Kahangi JKUAT’s Deputy Vice-Chancellor in charge of research, production and extension.

This has created the need to improve production through increased yields and better utilisation of resources.

The main rice growing schemes of Mwea, Ahero, Hola, Bura, Perkera, West Kano and Bunyala use paddy irrigation. The paddy system requires continuous flooding through large volumes of water. SRI grown rice, however, only requires sufficiently moist soils or alternate wetting and drying, drastically reducing water use.

“It had been previously believed that rice can only be grown under continuous flooding but SRI is changing that perception,” said Ms Kahangi.

The new system saves water by about 25 per cent to 50 per cent, allowing for the saved water to be used to expand the production area.
Water scarcity has been affecting most rice-growing schemes with frequent rationing affecting production. The situation is expected to worsen with increasing population and climate change.

Rather than planting a group of seeds together, the new method uses only one seedling per hole with a wider spacing of 25 cm by 25 cm.

This saves on inputs as farmers use 25 per cent of seeds used in the conventional paddy system and less fertiliser.

With wider spacing, rice plants get more sunlight, air and nutrients, allowing faster growth of roots and canopies, producing stronger stalks and more tillers.

Intermittent flooding of paddies enables the soil to hold more air, allowing plant roots to grow more profusely leading to effective nutrient uptake, healthier plants and better grains.

Irrigation is initially done on a cycle of three days under flooding and seven days without water, keeping the soil moist and at the same time allowing air to get into the soil.

When panicles start to appear, continuous irrigation is carried out with a layer of water 1cm to 2cm in depth being retained which is then stopped one to two weeks before harvesting to allow the field to dry and maximise nutrient uptake into the grains. Rather than manual weeding, JKUAT has also developed rotary weeding tools that mechanically mix the weeds into the soil. “We have come up with rotary weeders which are even drawing men into the weeding which was formerly done by women only,” said Ms Kahangi.

Farmers are encouraged to use organic fertilisers rather than chemical ones to enrich the soil. This further reduces input costs.

Increased yields

Use of less water is also expected to reduce water- borne diseases along with Malaria and Bilharzia.

One of the disadvantages of the new system, however, is that it requires more weeding since weeds tend to grow more rapidly under un-flooded conditions.

But the extra effort is compensated by increased yields of one to two tonnes per hectare.

By July this year, more than 1,800 farmers had been trained on the new system in the Mwea rice scheme through an initiative by JKUAT, the National Irrigation Board, and the World Bank.

JKUAT’s research team is also expected to release new improved rice varieties in the market following several years of research.
Since the original rice varieties such as Pishori and Basmati were introduced into the country, there have been no concerted efforts to improve them through breeding.

Current varieties grow very tall and fall with the wind leading to loss of grains. The new varieties being developed are expected to have stronger, shorter stalks with increased yields.

The new varieties are also expected to be resistant to rice blast which has in the past wiped out whole fields.

Available varieties are only grown in one season annually since they cannot produce seeds during the cold season.

Using cold tolerant varieties from Japan, JKUAT is breeding varieties that will grow during the cold season, increasing the rice growing seasons to two annually, doubling the country’s production.

“We are now in the 8th or 9th generation and they will be ready in less than two years,” said Ms Kahangi.

Along with the SRI system, the new varieties are expected to meet the supply deficit for local consumption and provide surplus for export.

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