IJMIE Volume 3, Issue 11 ISSN: 2249-0558 __________________________________________________________ A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A. International Journal of Management, IT and Engineering http://www.ijmra.us 32 November 2013 COMPARATIVE STUDIES OF FOUR PARAMETRIC MODELS FOR POTASSIUM ADSORPTION IN SOILS OF NYAMIRA COUNTY, KENYA Kenyanya, O  Muthengia, J.M.* Mbuvi, H.M.* Omayo, E.K  ABSTRACT Potassium is the third major nutrient after nitrogen and phosphorus. However, soil test for potassium often fail to reveal the true fertilizer demand in the field resulting to unreliable and inefficient fertililizer application to crops. This necessitated this field experiment to be carried out in soils of Nyamira county Kenya with an objective of fitting the experimental data into four parametric adsorption models and ascertain the most suitable adsorption isotherm which best fitted and described the studied soils. For adsorption studies 2.50 g soil samples were shaken with 25 ml 0.01 M CaCl 2 containing K concentration of 0, 25, 50, 75, 100, 125, 150, 175, 200, 225 and 250 mg L -1 using potassium chloride for 24 hours at 25±1 °C to achieve equilibrium concentration. Langmuir, Freundlich, Temkin and Van Hauy adsorption models were applied to the data to check potassium adsorption in the soils. From the results, the physical-chemical properties of the soils revealed that the studied soils were acidic in nature with a mean pH of 5.19 . The soils were non-saline with electrical conductivity mean of 0.25 mmhos/cm. The cation exchange capacity of the soil was 21.25 cmol/kg. Basic nutrients were low (Available K was 60.2 mg/kg, available P (Olsen) was 9.71 mg/kg.and the organic carbon found to have a mean of 1.82 .) By application of the  Chemistry Department, Kenyatta University, Kenya  Chemistry Department, JKUAT, Kenya