Farm water use efficiency assessment for smallholder pumped irrigation systems in the arid and semi-arid areas of Kenya

Abstract

Water use efficiency for irrigated agriculture still remains low.  This presents a risky trend in the near future due to diminishing water resources as well as rising population demanding increased food supplies.  The objective of the study was to investigate pumped irrigation methods used by smallholder farmers in the arid and semi-arid land environments as well as assess the water use efficiency during crop production under usual farmer management.  The study was carried out in Mitubiri location of Kakuzi division and Kithimani sub location of Yatta division, Kenya.  Observational study during the field transect walks in the study sites identified methods of irrigation used by the smallholder farmers, water conveyance as well as application methods and the soil physical properties.  Questionnaires were developed and administered to 80 farmers in order to find out the socio-economic status of the people and the agricultural practices carried out.  A detailed study was carried out in 10 experimental plots set in the study areas.  Water losses during conveyance and application were assessed in the experimental plots.  Of the five farms where water conveyance was through secondary canals, the mean water conveyance efficiency was found to be 81.4%.  Water application efficiency in the ten blocks under different crops grown i.e. baby corns (Zea mays L.), French beans (Phaseolus vulgaris L), tomatoes (Lycopersicon esculentum L) and water melon (citrullus lanatus) in the months of April to July 2009 was assessed.  On average, water application efficiency ranged from 19.5% to 30 % for the crops assessed which was far below the recommended range of 65% for surface irrigation methods.  The study hence shows that there is a need to improve water use efficiency in smallholder irrigated agriculture in order to conserve water and ensure no shortages of water during the times of high water demand.