Potassium Fixation on Soils Formed from Diverse Parent Materials in Akwa Ibom State

Abstract

The study was conducted to determine the fixation capacity of potassium from soils formed from diverse parent materials (coastal plain sand, beach ridge sand and sandstone) in Akwa Ibom State. Composite surface soil samples were collected from three representative locations.  A treatment solution containing 0, 20, 40 and 80mg/l of K prepared from Potassium Chloride (KCL) were added to 20g of soil in cups and the cups were carefully covered and allowed to incubate for 1,7,14 and 21 days respectively. The design was 3×4 factorial experiment fitted into a completely randomized design (CRD).  Each of the treatments was replicated three (3) times. At a set day, the exchangeable and water soluble K were extracted with KCL and K not extracted was considered fixed in the soils. The results indicated that, the soils were dominated with sand fractions, acidic to slightly acidic with low nitrogen and electrical conductivity. Organic matter varied from low to moderate. The amount of K fixed in SS soil was higher in day 21 (29.55) > day 7 (22.55) > day 1 (15.65) > day 28 (7.89) and gradually decrease with length of incubation. The amount of K fixed in the soil increased with increased in the rate of K added.  The BRS had the highest fixing capacity at day 28 (17.55mg/kg^-1) while the coastal plain sand had the least K (4.49mg/kg^-1). To reduce the risk of K fixed in these soils, the use of organic manure and periodic evaluation of soil K is recommended.