Assessment of Soil Acidity and Determination of Lime Requirement under Different Land Uses in Gumer District, Southern Ethiopia

Abstract

The study was initiated to assess the level of soil acidity and lime requirement of four types of land uses (forest lands, grazing lands, cultivated lands, and Eucalyptus tree plantation) and in replications from 0-20 cm soil depth. Lime requirement was evaluated by exchangeable acidity and buffer solution methods.  The data were analyzed by SAS software, version 9.1.  The study revealed that soils of cultivated and Eucalyptus lands were very strongly acidic with mean of pH 4.8 and 5.0, whereas soils of grazing lands were strongly acidic with pH 5.5 and forest lands were moderately acidic with pH 5.7and 5.6 in both kebeles, respectively. Meaningfully higher pH, OM, TN, CEC, exchangeable Ca²⁺, and Mg²⁺ were noted under forest lands as compared to the remaining land uses. However, meaningfully lower exchangeable acidity (EA) (1.06) and percentage acid saturation (PAS) (5.18) were obtained in the forest lands than in the other land uses. Significantly higher available P (2.54) was noted in the grazing land, followed by natural forest (1.77) land for Berchernamocheya kebele, and higher available P was recorded under forest (2.50), followed by grazing land (2.37) for Badnayegor kebele. Significantly higher exchangeable K⁺ (1.29) and Na⁺ (0.63) were observed in grazing land for Badnayegor and Berchernamocheya Kebeles, respectively. The results of the lime requirement revealed that using the SMP buffer solution method recorded 4.1-11.3 t/ha while using the exchangeable acidity method recorded 1.3-6.7 t/ha across the land uses for both kebeles. Based on lime requirement determination methods, the amount of lime required highly varies among the land uses. The investigation showed that soil acidification is a serious problem in the study areas.  Thus, integrated land management needs to be practiced to overcome the problem of soil acidification and achieve sustainable agricultural production.