Using minimum water to grow rice

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Kenya produces only 12 per cent of the annual rice consumption with the deficit being filled through imports. Whereas the country is capable of producing surplus, water shortage remains the major hindrance. A new technology that saves water could offer the ultimate solution.

Rice production is set to increase, with the use of a new method of growing paddy that is already boosting yields, reducing water usage and bolstering profits at the Mwea Tebere Irrigation Scheme in Kirinyaga County, the main rice farming region.

The Water Saving Rice Culture (WSRC) consists of five technologies that include the use of healthy seedlings, hand leveling, line planting, improved weeding and intermittent irrigation. “Water shortage is one of the biggest challenges in Mwea. Rice farmers are required to save water for irrigation and domestic use,” says Mr. Daniel Mwithia, an agronomist with the Japan International Cooperation Agency (Jica)-funded Rice-based Market-oriented Agriculture Promotion Project (Rice MAPP). The new technology is expected to change the way rice is grown to enhance productivity and profitability.

“Manual leveling after rotavation or animal traction in the field is critical at the land preparation stage. It ensures uniform water distribution to all seedlings.

It also results in successful transplanting and easy water management,” says Mr. Mwithia.

Seedlings: The WSRC also recommends use of healthy seedlings. The seeds are pre-germinated by soaking in water for 24 hours followed by incubation for another 48 hours to attain higher even germination.“Pre-germinated seeds are then sown at 100g per square metre. In the conventional method, seeds are sown at a high rate of up to 300g per square metre, which leads to elongated and weaker seedlings, with a higher incidence of disease,” he explains. Transplanting the seedlings should be done at three weeks, as this leads to higher yields.

Line planting: Another departure from conventional rice growing is line planting. With a spacing of 30cm by 15cm, an appropriate plant population is obtained unlike in random planting. Gapping should be done to maintain optimum population to maximize yields.

Weeding: Push-weeders should be used in weed control between the rows, according to experts. Two people can work on an acre of land using the weeder, says Mr. Mwithia.

Intermittent irrigation: This is the revolutionary part of WSRC. The ‘Alternate Wetting and Drying (AWD)’ involves three days of flooding up to 2cm in depth, followed by four days of draining or drying. The practice starts 10 days after transplanting and repeated for the next month. “Leveling is a key factor of intermittent irrigation because the method requires the water to spread evenly. Drained fields under this watering regime enable oxygen to get into the soil and saves water usage by more than 20 per cent,” says the agronomist.

First introduced in the main growing season of 2014, WSRC increased average yields per acre by 13 per cent from 23 bags to 26 bags. During the ration-second growth cycle, the yield per acre rose from nine to 12 bags. Equally, profitability in the main season rose from Ksh84, 000 ($ 840) per acre to Ksh92, 000 ($ 920). The technology comes at a time when the country is seeking better ways of improving rice production, as demand soars with a rising population. Available statistics indicate that the annual growth in rice consumption in Kenya is around 12 per cent. Overall, annual production is around 50,000 tons against a demand of 300,000 tones, forcing the country to import 88 per cent to cover the deficit. Most of the imports come from the Far East, mainly Pakistan. Kenya has the potential to produce over 540,000 tones with better farming methods and increased acreage. Located south of Mt Kenya in Central Kenya, Mwea Irrigation Scheme has 16,000 acres under paddy rice production. It has 4,000 acres of out-growers also under paddy production, according to the National Irrigation Board (NIB). The region accounts for 88 per cent of total Kenyan rice production. The scheme derives water from two main rivers – Nyamindi and Thiba, which flows by gravity from fixed intake weirs. It is then conveyed and distributed through open channels. The NIB concurs that water shortage is one of the biggest challenges due to increased demand by out growers. The project also calls for increased mechanization of farm operations to reduce overall labour costs. The project has received an assortment of equipment including 15 combine harvesters, 80 HP tractors for rotavation, and 30 levelers, Rice researchers say increased investment in research and development, price stabilization and adoption of the New Rice for Africa (NERICA) variety can also help boost production. Jica has been funding rice projects for decades in Mwea, Bunyala, Ahero and Bura irrigation schemes.

Kisumu County received $ 2 million grant in tractors and other farming equipment partly funded by Jica to help farmers in West Kano and Ahero irrigation schemes to revitalize and commercialize their rice production. Other partners in the project include the Government and farmers, who will contribute $600,000. “With mechanization, the overall cost of production will go down, improving farmers’ earnings. We want to boost rice production and create employment in the irrigation schemes,” said Mr. Jack Ranguma, the Kisumu County Governor, during the handing over of the equipment at the lakeside town recently. The tractors are also expected to curb rampant use of child labor working in the fields instead of attending school.