Soils and irrigation of three areas in the Lower Tana Region, Kenya : a comparative study of soil conditions and irrigation suitability

The soils and soil conditions of three areas situated in different physiographic positions in the Lower Tana Region of Kenya were investigated in respect of their suitability for irrigated agriculture. The soils vary widely in both physical and chemical properties. Most of the soils have an alkaline soil reaction. Salinity and sodicity vary widely from soil to soil and within the same soil. The soils are characterised by low to moderate infiltration rates and slow hydraulic conductivity. Possibilities for deep subsurface drainage vary In the three study areas. The soils behave differently under the same irrigation practices and management. The bulk of the soils are marginally suitable to not suitable for irrigated agriculture. The most limiting factors are salinity, sodicity, drainability, effective rooting depth, availability of oxygen for root growth and workability of the soils.