Characterization and Mapping of Soil Salinity Status at Small-Scale Irrigation Farm: The Case of Fantale Irrigation Project Sites

Abstract

Agricultural production and productivity can be adversely affected by the presence of excessive salts in soils particularly in semi-arid and arid areas. Knowledge of the salinity/sodicity of the soil and the quality of the irrigation water is essential for managing agricultural fields effectively and increasing the output and productivity of the lands. This research was initiated with the objectives of characterizing and Mapping of soil salinity status at small scale irrigated areas of Fantale district and identifying the most affected irrigation scheme so as to design appropriate soil salinity management. The study was conducted at Fentale district of Galcha, Gola and Dire Sade irrigation schemes. Soil samples were collected from the surface using augur, and from pits at different depth interval and analyzed for pH, EC, Na+, ESP, SAR, Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup>, and CEC. The result was compared with the standards set by FAO system to classify soil and water salinity. Accordingly, it was identified that Galcha irrigation scheme was characterized as sodic due to very strong sodium concentration with average ESP of 53.2% and EC 3.95 mmhoms/cm and pH about 9.25. On the other hand, Gola and Dire Sade Irrigation schemes were characterized as moderately and slightly sodic respectively. Sodium was the dominant soluble cation, followed by calcium, magnesium, and potassium in all soil depths and schemes. Beside primary Salinization of natural processes such as physical or chemical weathering parent material, and discharge Basaka Lake to the downstream, was the main source of salt build-up in the upper layers of the soil at Galcha irrigation scheme. On the other hand, irrigation water analysis indicated that water used for irrigation at all irrigation schemes were slightly sodic. Therefore, the study underscores the need for a scientific reclamation of sodic soils primarily at Galcha Irrigation scheme where sodium concentration in the soil was very strong.