Farming technologies to grow crops with less water, no pesticides

Agriculture sector is the backbone of Kenya’s economy, employing 70 percent of the rural population and accounting for 65 per cent of export earnings. However, agriculture’s share of national income is declining because of climate change. Nearly 98 percent of crop production is rainfed, and almost 50 per cent of animal production occurs in arid areas. The increased incidence of drought and unreliable rainfall are expected to significantly affect the sector. Kenya government is advising farmers to plant crops that need little water in dry areas.

The Government of Kenya was one of the exhibitors at Agritec Africa 2022 on 15-17 June at Kenyatta International Conventional Centre, Nairobi. Ministry of Agriculture showed how it is helping farmers start productive farming by growing crops that would survive the changing climate. This also helps growing crops in dry areas.

The government is seeking to improve productivity by encouraging farmers to use good agricultural practices. Such practices are conservation agriculture and water conservation.

Mr James Gitonga, sub-county agricultural officer, Kitui Rural Sub-County, Kitui County, spoke to Water Tower at the show. He said that the agriculture ministry encourages farmers to use two farming techniques. They are push and pull, and conservation agriculture.

Push and pull method

International Centre of Insect Physiology and Ecology (Icipe) with its partners created push and pull technology. This is an alternative to using chemical pesticides to kill pests. The technology cuts problem of insect pests like stemborers. Push and pull method also help to keep the soil healthy.

Stemborer moths lay eggs on maize or sorghum plants. Eggs hatch into larvae (caterpillars) that eat maize or sorghum leaves and burrow into the stem as they grow. The stemborer caterpillars hence eat the food the maize or sorghum would use to fill the grains.

Under this farming method, farmers use drought tolerant brachiaria grass and desmodium legume to cut these pests in their maize or sorghum fields.

Under push and pull strategy, three rows of brachiaria are planted around land under maize or sorghum. At the same time, one line of desmodium is planted after every three rows of maize or sorghum.

Desmodium produces a smell that stemborer moths don’t like, Mr Gitonga said. The smell from desmodium ‘pushes’ away the stemborer moths from the maize or sorghum crop. As result, the stemborer moths are ‘pulled’ by brachiaria, which is more attractive to them. The stemborer moths lay their eggs on brachiaria.

However, brachiaria grass does not allow stemborer larvae to develop on it because it lacks nutrients for the stemborer larvae. So very few stemborer larvae survive.

Mr Gitonga said push and pull farming increases farmers’ incomes by improving soil fertility, and maize production. It also gives farmers animal fodder throughout the year.

“Push and pull strategy increases production of maize [or sorghum] and improve soil fertility,” Mr Gitonga said. “Desmodium and brachiaria grass are high quality animal fodder plants leading to high milk production.”

What if a farmer is unable to get desmodium and brachiaria?

Mr Gitonga from Agriculture ministry says desmodium grows well in areas with enough rainfall. But brachiaria grows well in both high and low rainfall areas.

There are other plants farmers may use if they lack desmodium and brachiaria.

Mr Gitonga said farmers may plant dolichos instead of desmodium. Dolichos is a flowering plant in legume family. In Kenya, dolichos is known by many names, like njahi, nchaabi, and mbumbu.

“Dolichos is appropriate in dry areas because it’s drought resistant,” Mr Gitonga said.

Farmers may plant Napier grass when they are unable to get brachiaria. Napier grass works as brachiaria by pulling stemborers moths from sorghum and maize farms eventually reducing the pests’ population.

Napier grass is grown along boundaries of maize or sorghum crops.

In addition, Napier grass is mainly used as animal feed. It is fed directly to cattle or made into silage or hay. It can be harvested multiple times in a year.

Napier grass is best grown in warm, and tropical regions. It performs very well at temperature ranging from 25C to 40C.

Push and pull method kill striga weed, too

Striga is a parasitic weed which lives on maize, millet, sorghum, sugarcane, rice, legumes, and a range of weedy grasses. Striga weed requires a living host to germinate although it can then survive on its own.

Striga weed greatly cuts harvest for maize, sorghum, millet, and rice. It attaches itself to the roots of the crop thus robbing it of nutrients. An individual striga plant produces many thousands of tiny seeds that can remain viable in the soil for 15–20 years.

Scientists at Icipe were looking for ways to control striga weed. They found companion crops containing certain chemicals that naturally suppress striga, as well as having other economic uses for farmers.

Desmodium has a unique capacity to suppress striga growth and reduce the seed bank in the soil. Desmodium is planted in rows between rows of cereal crops.

Desmodium covers the surface of the ground between the rows of maize or sorghum. It puts a chemical into the ground that stops striga weed from growing on maize and sorghum.

Push and pull method that controls both stemborers and striga weed. At the same time, desmodium gives farmers fodder throughout the year.

“So very few stemborer larvae survive, no striga grows and maize or sorghum is saved in the new push and pull strategy,” Mr Gitonga said.

Conservation agriculture

Mr Gitonga said the government encourages farmers to use conservation agriculture. This is a farming system that promotes minimum soil disturbance or no tillage, covering the soil, and rotating crops, he said.

This improves biodiversity and natural biological processes above and below the ground surface. Conservation agriculture helps to increase water and nutrient use and crop yield.

Mr Gitonga said conservation agriculture helps reduce adverse effect of climate change. He explained three principles of conservation agriculture that Agriculture ministry advising farmers to use.

United Nations’ Food and Agriculture Organisation (FAO) advises farmers to grow diversified species in varied sequence. FAO says that if crop rotation is done well, it helps farmers have good soil structure with diverse types of soil organisms. It also helps prevent pests and diseases.

United Nations’ Food and Agriculture Organization (FAO) says conservation agriculture uses between 20 to 50 percent less labour. It thus contributes to reducing greenhouse gas emissions through lower energy inputs and improved nutrient use efficiency.

At the same time, conservation agriculture stabilises and protects soil from breaking down and releasing carbon to the atmosphere.

Conservation agriculture principles

1. Minimum tillage or minimum soil disturbance. Instead of ploughing the land, Mr Gitonga advises farmers to rip their land. In ripping, the farmer cuts a deep cut only where seeds would be planted. Other parts of the land where no seeds would be planted are left unbroken. Mr Gitonga said that after some time the undisturbed land between rows of plants becomes hard, thus unable to absorb water. So, the rainwater falling on this hard soil will be channelled to the ripped lines where plants are growing.“The major advantage of ripping is that the land left undisturbed between the rows acts as a roof,” he said. “So, rainwater collected on the undisturbed land is channelled to the ripped line where plants are planted.”
2. Maximum soil cover. Mr Gitonga said farmers must cover their soil with crop residues or crop covers. He told farmers to be leaving some crop remains on the farm after harvesting. “For example, when harvesting maize, don’t cut the stalks at the ground,” Mr Gitonga said. “Cut at least one foot above ground.”Farmers also could use live crops as soil covers. For example, by intercropping maize with beans, and maize with potatoes, Mr Gitonga said. He said that keeping a protective layer of vegetation on the soil surface suppresses weed. It also protects the soil from extreme weather and helps to preserve soil moisture.
3. Crop rotation. This is changing the type of crop from one season to the next. Mr Gitonga advises farmers to plant cereals in one season followed by legumes or pulses (beans) the next season. “This means that the next season’s crops will use the unused nutrients from previous season,” he said.Mr Gitonga told farmers to rotate deep rooted crops with shallow rooted crops. “Deep rooted crops will bring up deep nutrients to be used by shallow rooted crops,” he said. “This renews nutrients in the soil.”

Collecting rainwater

Mr Gitonga said farmers must also collect and store rainwater. For farmers whose farms are on a slope, he advised them to build terraces to reduce soil erosion.

In addition, he advised farmers who to dig ponds to collect rainwater. “If you can, build a pond in your farm to collect rainwater runoff for supplementing irrigation,” Mr Gitonga said.