ACIDITY STATUS AND LIME REQUIREMENT OF SOILS OF AMEYA DISTRICT, SOUTHWEST SHOWA, ETHIOPIA

Abstract

Soil acidity is one of the main factors that limit agricultural productivity in many parts of the world. Study was conducted at Southwest showa Ameya District on acidic soils collected from dominant crop fields of the four selected kebeles in South Westshowa Zone, Ameya District to determine the status, and extents of acidity, and determination of lime requirements to neutralize the acidity effects. The selected kebeles were Gulti Bola, Bero Salen, Dire Aroji, and Kechema Jiran. Field observation, and surveys of the study areas were carried out. Representative composite soil samples were collected from dominant crops field at (0-20cm) depth. Soil physicochemical (Texture, BD, pH, organic carbon, TN, Available P, CEC,PBS, exchangeable acidity, and bases) were analyzed following the standard procedures. Lime incubation study was carried out to determine amount of lime required to neutralize acidity of the soil to the targeted pH. Results of the study revealed that soil pH (H2O) ranged from 4.97 to 5.44 which rated as very strongly acidic to strongly acidic in reactions, and the values of soil textural class of the study areas were Sandy clay loam, and the bulk density of soils of all the study areas were in medium range. The values of CEC, PBS, AP, OM, and TN of the study areas were low, due to the low additions of organic matters or litters deposition in the agricultural croplands, and Continuous removal of basic cations by crops, intensive cultivation that enhanced leaching of basic cations, and washed away of exchangeable bases by rill, and sheet erosion .The results showed that incubation of soil using lime/ CaCo3 completely changed soil pH from very strongly acidic (4.97) to near optimum (pH of 6 to 6.5), and suitable for crop production. Based on results of incubation study, 9.16 t ha-1, of lime was required for soil of Gulti Bola, 9.47 t/ha for soil of Bero Salen, 9.53 t/ha for soil of Dire Aroji, and 9.75 t/ha of lime for soil of Kechema Jiren kebeles required to be applied to raise soil pH to the target pH values of 6 to 6.5.