EVALUATION OF AVAILABLE POTASSIUM DETERMINATION METHOS FOR DIFFERENT TEXTURE SOILS

Abstract

Determination of available K conducted by different methods. In Iraq;ammonium acetate (1M) consider the most widely used methods while few othersprefer 0.5M CaCl2 method. Implementations of suitable assessment for available Kconsider an important task to evaluate the amount of K fertilizer that should applyto soil. Therefore both methods (NH4OAc and CaCl2) were investigated andcompared with third suggested method (1M NaOAc) which considers a suitabletechnique to evaluate the available K in some investigation.Capacity of soils to release K was investigated in laboratory experiment.characterized by different texture class collected from Aurafia , Yousifiya andJaderia. 100g of the same soils used in experiment were treated with differentconcentration of K (0 ,50 ,100 and 150 Kg.h-1) and subject to wetting – dryingcycles 45 days. Available K was extracted and determined for five successivetreatments using wet and dry soils by NH4OAc , CaCl2 and NaOAc methods. Dataobtained indicate a significant correlation between extractable amount of K andthe levels of applied K to soils. The extractable amount of K for differenttreatment increased in the following sequence : NaOAc > NH4OAc > CaCl2