SOIL NUTRIENTS STATUS OF ORLU SERIES GROWN TO RAPHIA HOOKERI

ABSTRACT

The study was conducted at the Nigerian Institute for Oil Palm Research (NIFOR), Benin City, Edo State, Nigeria. The main objective of the study was to determine the physical and chemical properties and nutrients level in soils of upland (Orlu Series) grown to Raphia hookeri in NIFOR station Benin City. Soil samples were collected at two soil depths (0-30; 30-60) from three locations. The collected samples were air dried at room temperature and kept in bags after drying. Samples were taken for analysis to determine physical and chemical properties in the laboratory using standard methods. The results of the analysis indicate that the soil pH value of 0 -30 cm depth (top soil) is very strongly acidic while that of 30 – 60 cm (sub-soil) is extremely acidic with mean values of 4.64 and 4.32 respectively. Total nitrogen falls within the critical value recommended for crop growth while Organic Carbon was high at surface indicating more organic matter content compared. The mean of both depths showed available soil P was rated as high; the mean values of K, Ca, Mg, and Na and the study shows that all exchangeable bases reduced with increased in depths with mean values (0.3 cmol/kg, 0.69 cmol/kg, 0.32 cmol/kg and 0.15 cmol/kg) for top soil, and (0.25 cmol/kg, 0.66 cmol/kg, 2.27 cmol/kg and 0.13 cmol/kg) for sub soil respectively. Zinc and Copper decreased with increased soil depth while Manganese and Iron increased with increased soil depth. The soils of the study areas were dominated by the sand fractions and belong to the Sandy Loam textural class having a mean value of 860.66 and 849.85 % in depth 0-30 and 30-60 respectively. Clay increased significantly with increased depth in all slopes having higher clay content at depth 30-60 cm. Furthermore, this study revealed that there was generally low and inadequate macronutrient to sustain the full potential of the Raphia Hookeri. It also revealed that high micronutrient (Fe, Mn, Zn, and Cu) availability across the fields suggests that the nutrients are in abundance in the experimental area.