The micronutrient status of some soil supporting oil palm plantationin Nifor, Benin City, Benin
This study was conducted to assess the micronutrient status of soils under three different management practices at the Nigerian Institute for Oil Palm Research (NIFOR), Benin City, Edo State, Nigeria. Soil samples were collected from three different fields Research (NIFOR), Benin City, Edo with different management practices. The samples were air dried and analyzed for Fe, Zn, Cu, and Mn contents using standard method. Data was subjected to ANOVA and correlation studies. Result showed that soil micronutrient status was generally low as revealed by their estimated levels of availability: field 53 (Mn = 0.0333; Zn = 3.723; Cu = 2.04; Fe = 6.4), field 56 (Mn = 0.0367; Zn = 3.737; Cu = 1.12; Fe = 7.0939), field 71 (Mn = 0.0167; Zn = 3.860; Cu = 2.89; Fe = 7.243). Fe and Zn were above critical level for the 3 fields. Mn was below the critical level for the 3 fields and was significantly higher in field 56 (Orlu and Kulfo series) (p≤ 0.05). They were all similar. Fe was significantly different in field 53 (Kulfo and Alagba series) but similar in fields 56 and 71 (p≤ 0.05). Cu was significantly different in the 3 fields tested with field 71 (Orlu and Alagba series) higher than the critical level. Correlation studies showed that pH had a positive and significant correlation with Fe and Zn as observed in fields 71 and 56 (r = 0.9934, P≤ 0.05) and (r = 0.9997, P ≤ 0.05) respectively. Cu was the only micronutrient that has correlation with clay on each of the fields: 53, 56 and 71 (r = 0.9929, P≤0.05) (r = 0.9988, P≤ 0.05) and (r = 0.9967, P ≤ 0.05) respectively. Strong correlation existed between clay and Fe in field 53 (r = 1, P≤ 0.05). The concentration of the micronutrients (Fe, Mn,Zn Cu), in field 53 were not extreme (neither the highest nor lowest) when comparing the three fields indicating that BMP (Best Management Practice) may be the best for maintaining good micronutrient level in soils supporting oil palm. Fields 53 and 56 is adequate in Fe and Zn but not adequate in Mn and Cu while field 71 was adequate in Zn, Fe, and Cu but not in Mn. Based on the result of this experiment, adequate fertilizers of these micronutrients as their respective sulphates or impurities should be added to maintain proper micronutrient level.