Irrigation & Drainage Systems Engineering

Using Drip Irrigation to Mitigate the Effects of Drought in Food Production: A Case Study of Production of Beans during Dry Spells in Uasin Gishu County, Kenya

Abstract

Rioba DO*, Kosgei JR and Kipkorir EC

Over 80 percent of Kenya’s freshwater withdrawals are utilized in agricultural production. The increase in human population means that even more water will be channeled towards food production. Improving water productivity is the most appropriate strategy for increasing food production for a fast growing population due to its consideration of the sustainability of water resources. Kenya predominantly depends on rain-fed agriculture for its food production, and this exposes the country to acute food shortages during droughts. Beans (Phaseolus vulgaris L.) are the primary source of protein for most households in Kenya. Despite this fact, there is a supply deficit during dry spells. An irrigation project was carried out at Moi University with an objective to study the effect of deficit irrigation as a mitigation measure to curb the shortage of beans during dry spells while ensuring sustainable use of water resources. This was carried out through modelling of water productivity (WP) and yield (Y) of beans using the FAO AquaCrop model. Field experiments were set up in a Randomized Complete Block Design (RCBD) arranged in split plots and replicated three times. Two water treatment strategies were employed (deficit irrigation, full irrigation). In the full irrigation supply, the crop was kept at 100% of irrigation requirement (T100) and data collected from these plots was used in Aqua Crop model calibration. There were three levels of deficit irrigation used: 80%, 60%, and 50% of irrigation requirement (T80, T60, T50), these were used in model validation. The highest WP, as well as the lowest yield reduction of 2.4%, was observed in the T80 treatment, this signifies water savings of up to 20%, which translates to 750 m³/ha. The highest yield reduction of 59.8% was obtained in T50 treatment, coupled with a drop in WP. Deficit irrigation results in yield reduction as observed in this study, but the amount of water saved can be used to irrigate more land or be utilized elsewhere. Consequently, it is necessary for Kenya to adopt deficit irrigation to ensure food security during dry spells while at the same time ensure sustainable water use.