ICRAF scientists launch a major project in western Kenya

The famine and atrocities in the Sudanese region of Darfur are in the news headlines every day, but a few hundred kilometres to the south another massive human disaster is unfolding. Last year, the lack of good rains caused major crop failures all over Kenya and an estimated 3 million people are facing the threat of starvation.

This no surprise in a country with such an extremely stressed ecosystem” says Lou Verchot, Lead Scientist for Climate Change and Soil Fertility with the World Agroforestry Centre (ICRAF). “There have always been droughts, but over-cropping on marginally productive land and other unsustainable farming practices make farmers very vulnerable to such natural variations as a lack of rain.”

The situation in western Kenya is aggravated by a number of other problems like overpopulation – with as many as 1600 people/km2 the density is comparable to that of an average city. Inappropriate farming practices have created large areas of degraded land where erosion has stripped away fertile soil. The Katuk–Odeyo gully scarring the landscape to a depth of up to 25 m for more than 45 km is one of the most daunting examples.

As Verchot states, “Soil erosion creates major problems. Small-scale farmers can no longer successfully grow certain food crops and are forced to change their farming practices, but lack the knowledge and resources to do so. Compelled by necessity they continue growing the wrong crops in the wrong places causing even more damage and degraded land.”

Further downstream the soil erosion creates a different problem for the fishermen of Lake Victoria. Millions of tonnes of fertile soil wash into the lake causing an explosion of water hyacinth that clogs
ports. Eutrophication of the lake has destroyed the local fishing industry.

“To solve these problems, farmers in western Kenya must change their farming practices to more sustainable ways of land use” says Lou Verchot: “It’s the maize that keeps farmers in poverty: the people are not starving, but it’s a vicious cycle. The farmers make no money so they cannot invest in their land. The land degrades and productivity decreases, so they get poorer. We have to find more sustainable ways for subsistence farmers to make a living, and this is what our research is addressing.”

The Western Kenya Integrated Ecosystem Management Project, led by the Kenya Agricultural Research Institute (KARI) is looking at ways to rehabilitate large areas of degraded and abandoned land. Verchot and his team have combined field surveys and satellite imagery with advanced analytical techniques developed by two ICRAF scientists, Markus Walsh and Keith Shepherd to create maps of degraded land in the river basins of western Kenya. These maps are used to stratify the landscape into: intact, moderate, or highly degraded land in lowland, mid- or upland portions of each river basin and to help select research sites.

The research team has identified nine large 100 km2 blocks of land, spread out across the landscape of western Kenya. In each block 20 focus areas each of 64 ha have been randomly selected. Activities will be carried out within each focus area. Overall the project will work with an estimated 8,000 – 12,000 households. Lessons learned from the research will be applied to other areas with severe soil erosion problems.

With an initial grant of US$4.5 million from the Global Environment Facility (GEF) and the World Bank, the project will promote tree planting and more sustainable agricultural practices to regenerate the scarred landscape.

The sheer size and scale of the project are impressive and project leader Lou Verchot argues there is a good reason for this: “You solve largescale problems with largescale solutions. In the past we often focused on fieldscale problems, found viable solutions for one specific location and then sought out where these solutions could be applied elsewhere in the landscape. For example, we introduced a specific type of fertilizer tree and studied whether it would improve soil fertility, but this is not the solution for complex problems on a landscape level.

Take the example of the Nyando River basin where farming practices on the upper slopes impact farmers in lower areas. You cannot address this kind of problem with one simple solution. The project we are working on therefore starts at the landscape level, applying landscape diagnosis tools that ICRAF scientists have developed over the past 7 years.” After identifying the intervention areas the scientists will work with local farming communities to experiment with alternatives to unsustainable agriculture practices.

At the moment, most farmers grow a number of annual crops like maize, millet and beans. Severe soil erosion causes crops yields to be lower every year, and in severely eroded areas yields have declined by up to twothirds. More sustainable forms of agriculture – including tree-based enterprises such as orchards and fodder plantations for livestock – are more promising in the long term. They can halt soil degradation, rehabilitate degraded areas, and thereby raise crop yields.

Trees will also contribute to reducing global warming through carbon sequestration. Trees absorb carbon as they grow and thereby reduce the amount of carbon dioxide (CO2) in the atmosphere. One of the innovations of this project is that the scientists will explore the opportunities for farmers to sell carbon credits to countries that need to meet their national CO2 reduction targets agreed to under the Kyoto Protocol of the Climate Change Convention.

An aerial view of farms in western Kenya Photo by Andrew Pinney

Despite the promise of the tree-based production systems, Verchot does acknowledge that it will be difficult to change long-term farming practices overnight: “We will create demonstration sites where we will invite farmers to find out about the opportunities available. Experiences in the past have taught us that farmers understand the importance of trees and when you give them tree seedlings they will plant them. I am convinced that when we experiment directly with farmers we can jointly bring about the necessary changes. Through the diversification of regional agricultural production into fruits, fodder, timber and the selling of carbon credits we expect to see an increase in the income of farmers.”

Periodic drought is part of the natural situation in many parts of Africa, as the current situation in the region starkly reminds us, and tree-based production systems may be less vulnerable to such climate extremes.

Trees have an important advantage in that that they improve not only soil fertility, but also soil structure and the waterholding capacity of soils. Improving overall soil quality will play an important role in maintaining the productivity of crops and fruits in dry years.

“That’s the value of this new approach,” emphasises Verchot enthusiastically. “We are restoring the ecosystem and increasing the income of subsistence farmers simultaneously. Farmers will be much better prepared for future droughts.” Although he also warns not to be overoptimistic, “The problem of degraded lands in western Kenya was created over decades, and is probably going to take decades to solve.”