EVALUATING SOIL CONSTRAINTS ON THE GROWING OF OIL PALM (Elaeis guineensis) TREES IN AKWA IBOM STATE, SOUTHEAST NIGERIA
1Usuah, P. E. & N. M. John2
1Department of Soil Science and Land Resources Management, University of Uyo, Uyo
2Department of Soil Science, University of Calabar, Calabar
ABSTRACT
The study was carried out in 2016/2017 to evaluate soil constraints on the growing of oil palm (Elaeis guineensis Jacq) tress in Akwa Ibom State of Nigeria. Auger samples were taken from 21 oil palm growing locations at 0-25, 25-50, 50-75, 75-100 and 100-125cm depths, spread to cover much of the state. Each location was assessed on the basis of terrain, depth of soil, drainage, soil texture, and chemical properties such as pH, N, P, organic C, exchangeable Ca, Mg, K, and ECEC. The study showed that terrain at the locations ranged from “nearly level” (0-2%) to “strongly sloping” (4-7%). Soils were deep, with no impenetrable-layer within the 0-125cm depth. Drainage was good except at three locations with high water table. Soil texture was mostly loamy-sand (LS) to sandy loams (SL) down to the 125cm depths. Calcium and Mg ions dominated the exchange complex, creating undesirably wide Ca:K, K:Ca, K:Mg and Mg:K ratios and, thus, conditions for nutrient imbalances. Exchangeable K values were very low (0.05 -0.25 cmol kg-1 and 0.05-0.10 cmol kg-1 for the 0-25 cm and 25-50 cm depth respectively). Mean values of organic C were 25.08 g kg-1 and 20.06 g kg-1 for the 0-25 cm and 25-50 cm depths respectively. Mean values of available P were 15.31 mg kg-1 and 14.72 mg kg-1 for the 0-25 cm and 25-50 cm depth respectively. Total N levels were very low, with mean values of 1.11 g kg-1 and 0.91 g kg-1 for the 0-25 and 25-50 cm depth respectively. The study found that relatively very high levels of exchangeable Mg, very low levels of exchangeable K and very low levels of total N, along with poor drainage and steep slopes at some locations constitute serious constraints on the growing of oil palm trees in most of the state.
Keywords: Oil palm, soil constraints, soil management, Akwa Ibom State, Nigeria
