DEGREE OF ACIDITY RELATED SOIL CHEMICAL PROPERTIES AND EFFECT OF LIME RATES ON P-ADSORPTION CHARACTERISTICS OF WAYU TUKA DISTRICT, WESTERN OROMIA, ETHIOPIA

Abstract

ABSTRACT

Soil acidification and Phosphorus deficiency are major challenges to acid sensitive crop production in most of the highlands of Oromia. Study was initiated to evaluate degree of acidity related soil chemical properties and impact of lime (0, 3, 5, 7 and 9 t ha^-1) rates on P sorption characteristics of acidic soil. Analysis of soil chemical properties (pH, exchangeable acidity, Aluminum saturation, available and total P, soil P-sorption characteristics and 90 days Greenhouse incubation were employed using standard laboratory procedures to evaluate effect of lime rates on acidity related chemical properties, P-sorption characteristics and percent increment of available p before and after incubation.  Result of soil pH, revealed that all soils from studied sties fallen in very strongly acidic (4.63-4.89) media. Values of soil exchangeable acidity, percent acid saturation and Al saturation of soils ranged from 1.43-2.49cmol (+) kg^-1 soil, 5.36-9.37% and 3.57-6.28%, respectively. Available P before liming varied from 7.07-8.02 ppm and qualifying low range. However, due to application of lime, there was decrease of average percent total p- sorption of soils and ranged from 93% in the control to 57% at 9 t ha-¹ lime rates. Moreover, percent increment of average available P ranges from 7.2% in the control to 43.6% for 9 t ha^-1 lime. The positive values of R² values of Langmuir regression equation indicated, there was strong positive relationship of increment of P availability with lime rates incubated soils. Therefore, attention shall be given to restore continuous cultivation of acidic soils of study sites using reclamation options.