Fertility Status of Biakpan Rubber (hevea Brasiliensis) Soils of Cross River State, Nigeria

A study was carried out at Biakpan rubber estate in Cross River State, Nigeria to evaluate the fertility status of the soils. Three profile pits at random points within the estate were sunk representing the crest, the middle slope, and the valley bot- tom. Five samples were collected from each profile at 0 – 25cm, 25 – 50cm, 50 – 75cm, 75 – 110cm and 110 – 170cm depth. Fifteen representative soil samples were bulked as composite for each depth and were analyzed using standard labor- atory procedures. The result of the study shows that sand, clay, and silt fractions ranged from 52.4% - 67.80%, 18.20% - 36.20%, and 10.00% - 15..40% with means of 57.76%, 28.20%, and 13.24% respectively, decreasing from the top to lower profile. Soil texture for the 0 – 50cm was sandy loam and 50 – 170cm was sandy clay loam. The soil's pH was strongly acid (5.18 – 5.60). Total N, available P, exch. Ca and Base Saturation was low, with a high Exch Acidity. OM was adequate at 0 – 50cm (fertility depth). Exch. K and Mg and ECEC were within adequate limits of rubber trees. With adequate depth and textures of the soils, adoption of agronomic practices with leguminous cover cropping and guided organic and calcium-based fertilizers can overcome the fertility limitations in Biakpan rubber plantation soils.