Abstract:
Oil palm is unrivalled in its ability to convert solar energy into dry matter and vegetable (palm) oil. This process requires a large amount of nutrients, which must be supplied through soil or fertilizers. Good nutrients management, which included a site - specific nutrient management plan, is important to achieve high yields response of palm oil.
Soils collected from thickly populated Oil palm plantation in each Local Government Area of Edo State, where oil palm strived well were investigated for their nutrients status and moisture retentive holding capacity within the range of 0 – 15 cm, 15 – 30 cm and 30 – 45 cm respectively. The pH was measured in ratio (1:1) soil-water using a pH meter. Organic carbon content was by wet oxidation Walkey Black method, Nitrogen was by macro Kjaldahl method, Exchangeable bases was by Neutral Ammonium acetate method, Exchange acidity was by Normal Potassium chloride method and particle size analysis by Hydrometer method.
The result obtained showed that the soils were sandy to clayey in the far Edo North, and well drain in soils of Edo Central and South, highly susceptible to leaching of nutrients and the soils were acidic to slightly acid. The calcium, magnesium, and potassium compared well with the (sufficiency threshold) critical level for soils of Edo North, but low to moderate for soils of Edo central and Edo south of Edo state.
Generally, the organic carbon, organic matter, total nitrogen, available phosphorus are far below the critical level for all the soils. The effective cation exchange capacity (ECEC) is fairly good in soils of the Edo North but very low in the soils of the Edo Central and South. The Carbon/Nitrogen ratio is fairly good (below 20) because it has the potential to release nitrogen to the crop.
The recommended sufficiency threshold requirement for oil palm production ranges are as follows:
Organic carbon - 1 - 5%
Organic Matter - 3 -15%
Total Nitrogen - 0.1 - 0.4%
Calcium - 2-10 meq/100g soil
Magnesium - 0.1 - 0.5 meq/100g soil
Na - 0.1-0.4 meq/100 soil
Potassium - 0.01 - 0.4 meq/100g soil
pH - 5.60 - 6.00
Available phosphorus - 8.00 to 15.00 mg/kg
ECEC - 10.00 - 20.00 meq/100g soil
Carbon/Nitrogen ratio - 10-20
The Data obtained for soil physioco-chemical properties needs to be ameliorated to improve the soil structure and the nutrient status.
