Because we are just completing the model, it is premature to evaluate the impact of the project. However, our findings on why farmers are reluctant to invest in fertilizer has attracted attention from several foundations and other groups interested in increasing the productivity of African farming systems. Our findings on the rapidity with which soil fertility can be reduced has been presented both to farmers and to people working with non-governmental organizations and the extension services. We also have presented data on what is required to restore soil productivity.
impact statement issue
Over half of the population with which we work in the Kenyan highlands earns less than $1 per day and most of these people derive most of their livelihoods from agriculture. Because of high fertilizer prices, soil amendments are sparingly used, resulting in severe soil degradation. A consequence of soil nutrient depletion is markedly reduced crop yields which further reduce household income. The goal of this project is to understand why many Africans are trapped in poverty and how environmental degradation affects household livelihoods.
impact statement response
A team of economists, sociologists and agricultural scientists (crop, soil and animal sciences) have worked together to understand the economic and biophysical functioning of the smallholder farming system in the highlands of Kenya. In addition to collecting empirical research on household incomes, agricultural decision-making and on crop and livestock productivity, we have developed a dynamic, non-linear model to predict behavior of the system after different agricultural and economic interventions. We have worked with more than 300 farmers in Central and Western Kenya on this project and with Kenyan and international organizations.
impact statement summary
Through integration of the social and biological sciences, this research has contributed to our understanding of how smallholder farmers in the densely populated Kenyan highlands decide to invest in their natural resource base. By using a chronosequence of land converted from forest to agriculture at eight different times from 100 to three years ago, we have enhanced our understanding of soil degradation and repletion in the East African highlands where soil depletion is common. Within approximately 20 years, continuous cropping sharply reduced the nitrogen and organic matter content of soils. Restoring soil fertility is difficult because the levels of fertilizer that farmers can afford to apply do not pay for themselves in terms of increased maize yields making the investment unprofitable.
