Kinetics of potassium release and fxation in some soils of Ogun State, Southwestern, Nigeria as infuenced by organic manure

Abstract

Purpose The study investigated the efects of poultry and goat manures on the kinetics of potassium fxation and release in some sandy loam and loamy soils of Ogun State, Nigeria. Methods The treatments consisted of poultry and goat manures applied at 25 g and 100 g/5 kg soil set in completely randomized design with three replicates. Potassium fxation and release kinetics were computed from the analytical data. Results Experimental soils was sandy, slightly acidic, low in nutrients with 80% fxed potassium. However, manure application resulted in 74% reduction of the amount of K fxed by the soils. Elovich and power functions had the best ft for K released in soils treated with goat manure. The K release pattern in poultry manure-amended soil is best described by the parabolic difusion, Elovich, and power functions, while the frst-order equation described K release in soils treated with cattle manure. The potassium release rate constant correlated positively with K uptake. Conclusion The ability of the studied soils to fxed K was reduced with the application of organic manures. Potassium fxation decreased with increase in organic manure rates, 100 g/5 kg soil tends to be the optimum rate, and poultry manure had greater efect on the fxing and releasing power of K.