Farmers embrace no-tillage system to improve yields

Agricultural experts are lauding the steps Kenyan farmers are making in adopting a no-tillage system of farming that increases yields, but warn that failure to implement it quickly could lead to chronic land degradation and soil erosion that will ultimately threaten food production.

The no-tillage system entails planting crops into soil that has remained unploughed after the harvest of the previous crop.

Such cultivation has proven to have the potential, if carried out in conjunction with other appropriate farming practices, to improve food production, cut down labour cost in the farm by up to 20 per cent and stabilise threatened rural livelihoods.

Constant tillage threatens the health of the topsoil, which is paramount for better crop yield since it provides a habitat for organisms, including billions of beneficial microbes, nitrogen-fixing fungi, nutrients and earthworms whose digestive tracts transform the fine grains of sterile rock and plant waste into fertile soil.

On average, the earth is covered with little more than three feet of topsoil. Estimates from the Food and Agriculture Organisation have indicated that the world loses about one per cent of its topsoil every year to erosion, mostly caused by agriculture.

With scientists insisting that the topsoil cannot be made overnight since it is regenerated at a very slow rate of an inch or two over hundreds of years, farmers are being urged to adopt the no tilling method as a means of protecting the topsoil and improving food production.

Some Kenyan farmers plant seed directly into unprepared land immediately after the onset of rains, regarding it as a coping mechanism. Scientists are warning that failure to take up the no-tillage system could have serious repercussions for Kenyan agriculture.

“When a farmer tills, it means they are removing weeds, mixing in soil amendments like fertilisers, and shaping the soil into rows for crop plants and furrows for irrigation,” says Dr Kaheria Muriuki, a scientist from the Tegemeo Institute of Agriculture who is actively involved in pushing for no-tillage farming. “This results in adverse effects like soil compaction and death or disruption of soil microbes and other organisms, while washing or blowing away topsoil through erosion.”

“No-till farming avoids these effects by excluding the use of tillage. This way organic amenities and crop residues are retained on the surface of the soil and sowing is done with minimum soil disturbance,” he says.

The zero tillage system has become a success story in countries where it is practiced by farmers en masse. In Bangladesh, India and Pakistan, for example, zero tillage has reduced the demand for water in rice and wheat farming on almost a million hectares of land. While rice and wheat are important for southern Asia’s food security, yields had been stagnating and soil quality deteriorating.

But a ‘rice–wheat’ farming system, which has a summer ‘wet’ crop of rice — during the monsoon season — and a winter ‘dry’ crop of wheat, gave scientists the leeway to introduce no-tillage farming there in 2009.

The wheat seeds germinate in residual water left by the rice crop, saving up to a million litres of water per hectare. This farming technique has been widely hailed for cutting down land degradation by 50 per cent.

All scientists agree that the only problem with the zero tillage system is the over reliance on herbicides, as farmers try to clear weeds in otherwise untilled land, which may affect the quality of the crop.

“You see even if you tell farmers to go weed out manually, it is almost impractical for farmers to do it all in their big pieces of land,” says Zipporah Ndeti, another scientist pushing for the adoption of no-tillage in Kenya. “We are still looking for innovative and less laborious ways of doing away with weeds. We crack that and zero tillage farming will define farming in Kenya.”