EVALUATION OF AVAILABLE POTASSIUM DETERMINATION METHOS FOR DIFFERENT TEXTURE SOILS

Abstract

، اﻟﺰراﻋﻴﺔ ﻟﻠﻌﻠﻮم دﻳﺎﻟﻰ ﻣﺠﻠﺔ5)1: (91-104،2013اﻟﺴﻼمواﻟﻘﻴﺴﻲ 104 Sparks , D. L. 1980. Chemistry of soil potassium in Atlantic coastal plain soil. Soil Sci. and Plant Anal. 11:435-449. EVALUATION OF AVAILABLE POTASSIUM DETERMINATION METHOS FOR DIFFERENT TEXTURE SOILS Omar T. Al-Salam Shafiek C. AL-Kaysi *Dept. of Soil Sci. and Water Resources - College of Agri. - Univ. of Baghdad. ABSTRACT Determination of available K conducted by different methods. In Iraq; ammonium acetate (1M) consider the most widely used methods while few others prefer 0.5M CaCl 2 method. Implementations of suitable assessment for available K consider an important task to evaluate the amount of K fertilizer that should apply to soil. Therefore both methods (NH 4 OAc and CaCl2 ) were investigated and compared with third suggested method (1M NaOAc) which considers a suitable technique 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 and Jaderia. 100g of the same soils used in experiment were treated with different concentration of K (0 ,50 ,100 and 150 Kg.h -1 ) and subject to wetting – drying cycles 45 days. Available K was extracted and determined for five successive treatments using wet and dry soils by NH4 OAc , CaCl 2 and NaOAc methods. Data obtained indicate a significant correlation between extractable amount of K and the levels of applied K to soils. The extractable amount of K for different treatment increased in the following sequence : NaOAc > NH 4 OAc > CaCl 2 .