Abstract:

The presence of excessive salts/sodicity in soils, particularly in moisture-stressed areas, can have detrimental effects on agricultural outputs, having in depth knowledge on the salinity/sodicity of the soil and water is essential for managing agricultural fields for sustainable production and productivity of the limited lands. Accordingly, the assessment was conducted to characterize and map the status of soil and water salinity of selected small-scale irrigation schemes in Borana zone and to design appropriate its management systems. The study was conducted at six irrigation schemes including Qadalle, Arganne, Sabba, Sabboqqo, Jirarsa, and Bule Koloba which found at Yabello, Moyale, Miyo, Dillo, Teletelle and Elawayya districts, respectively. Surface soil samples were collected from surface using auger,as well as from opened pits at different depth interval and important parameters such as pH, EC, Na+, ESP, SAR, Ca2+, Mg2+, K+, and CEC were analyzed using different methods. The results obtained were classified in to different soil and water salinity classes depending on the standards set by FAO. As a result, 37% of the studied schemes were characterized as saline with very strong salinity contents in opened profile pits. Laboratory results of irrigation water quality of the study area indicated that 36.11% and 27.79% of samples were classified high to very highly saline, whereas, 55.6% was very highly sodic, which confirmed that this water is unsuitable for irrigation purposes. Arganne irrigation scheme is characterized as moderately and slightly sodic respectively. Particularly, very high sodicity was recorded at Qadalle irrigation scheme in Yabello district. Therefore, it is very important to immediately take action to amend and improve them according to their level of severity by various methods.