Towards Sustainable Land Use in Vertisols in Kenya: Challenges and Opportunities

Abstract

Vertisols are heavy clay soils with 30 to over 70% clay dominated by smectite mineralogy. They are the most widely distributed soils worldwide located mainly in tropical and sub-tropical regions. In Africa, they occupy about 3.5% or 99 million hectares of the landmass located mainly in eastern Africa. In Kenya, they occupy about 5% or 2.8 million hectares of the landmass and occur mainly in arid and semi-arid areas (ASALs). They are potentially very productive soils because of their high cation exchange capacity and water retention, moderate soil fertility and low salinity/alkalinity problem. However, their poor infiltration and internal drainage result in severe management problems. Traditionally, the Vertisols in Kenya were and still are used largely for extensive livestock grazing, however, due to increased population pressure and emigration of people from humid high potential areas to the ASALs; they are being converted to arable cropping. Vertisols cropping in Kenya is, however, a new utility system being embraced enthusiastically in spite of the serious management constraints observed. The major constraints include water logging and tillage difficulties, which pose serious challenges to their utilization for cropping in the country. In this chapter, problems and challenges associated with the ecosystem, population pressure and traditional and current land use including livestock grazing and arable cropping in the Vertisols are considered in relation to sustainable land use and management. In conclusion, views on the way forward towards sustainable land use and management of the Vertisols including proposals E.C. Ikitoo ( ) Department of Soil Science, Moi University, Eldoret, Kenya e-mail: ikitoo.caleb@gmail.com on stocking rates and cropping systems for maintaining the soil fertility and productivity while minimizing soil erosion and land degradation are given. Use of the drainage landforms (DLs) increased maize and sunflower grain yields by 5-57% and above-ground total biomass significantly.