Analysis of Soil Texture, Furrow Geometry, and Infiltration Rate for Improving Water Application Efficiency

Soil texture, furrow geometry, and infiltration rate are the main characteristics for improving water application efficiency. Substantial amounts of diverted irrigation water are often lost because of poor water control, inefficient irrigation conveyance systems, poor on-farm water management, or poor application practices. Field experiments were conducted on three farm plots within the command area for water availability and accessibility under the Melka Hida small-scale irrigation scheme in the West Guji Zone of Oromia Region, Ethiopia. The physical characteristics of soil, including depth, particle distribution, textural classification, bulk density, field capacity, and permanent wilting point, were studied and the results are presented. Furrow parameters including slope, width, length, and shape geometry were measured. The cumulative infiltration and infiltration rates were also recorded. The results show that irrigation application efficiency ranged from 57 to 64% with an average of 61%, indicating that about 40% of the applied water was not used by crops. The storage efficiency ranged from 79.6 to 81.6% with an average of 80%. Soil moisture measurements showed that crops were water stressed during the experimental period. Application efficiency decreased with increasingly steep slopes and cutoff times, greater applied depth, and high inflow rate in the study area. Unavailability of irrigation water control structure, weakness of water users’ associations, and maintenance of furrows and steep slopes were observed as the major causes of inefficient water management in the Melka Hida irrigation scheme.