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Pedogenic forms and distribution of potassium in soils along a complex toposequence within Forestry Research Institute of Nigeria, Ibadan

O.A. Fawole
R.O. Ojedokun
L.O. Asabia
H.O. Shaib-Rahim
A.I. Oluwaponle


The study was designed to examine the forms and pedogenic distribution of potassium in soils formed along a toposequence within Forestry Research Institute of Nigeria, Ibadan. Four (4) profile pits were established, described and sampled. Particle size, soil reaction and organic matter were determined in addition to exchangeable K, solution K and Fixed K which were determined using flameĀ  photometer. Results of particle size analysis showed that the silt content is low and varied randomly within the profiles possibly due to their location on the topography. The clay content was relatively high in the genetic B horizons. The exchangeable K, solution K, fixed K and total K varied randomly across the profiles, and this can also be attributed to the topographic positions. Results also showed that there is a high correlation between clay and exchangeable K and between total K and organic matter. This is an indication that soils with high clay content are likely to be rich in exchangeable K and where organic matter in the soil is high, the soil is likely to have a high value of total K

Key words: Toposequence, Pedogenic, Potassium