Continuous and coherent hard rock between 10.0 and 50.0cm of topsoil can considerably impede crop production. A field survey was conducted in 2006 to assess the physico-chemical properties, Fa and Pp of lithosols from six locations (Muvur, Digil, Vimtim, Gella, Lamorde, and Madanya) in Mubi area, Northeast Nigeria. Soils were sampled at 0-20, 20-50, and 50-100 cm depths in each of the six locations for the analyses of particle size distribution, bulk density, water holding capacity, pH, EC, OC, %N, avail P, K, CEC, TEB and land qualities including Fi and Pi indices. The soils were generally loam textured with low SOM levels, slightly acidic reactions and low soil nutrient amounts. The Fa index for the lithosols rated low (31.80 at Muvur and Vimtim) to good (51.5 at Digil) for rain-fed agriculture and excellent for orchard in all locations. The Pf index was rated good (55.4 at Gella) to excellent (90.50 at Madanya) for rainfed agriculture and excellent for orchard in all locations. The coefficient of improvement (Ci) for fertility index (Fi) for the soils showed that rain-fed agriculture can be improved by 1.54-2.54 times while orchard by 1.11 times only. The Fa index rated extremely low (2.31 at Gella) to moderate (51.12 at Vimtim) for rain-fed agriculture and low (11.25 at Gella) to moderate (58.32 at Madanya) for orchard. Accordingly, the soils can be classified varying from PII(S2) (good or moderate at Vimtim) to PV(N2) (extremely low or not suitable at Gella) for rain-fed agriculture and from PII(S2) (good or moderate at Madanya) to PIV(N 1) (low or presently not suitable at Gella) for orchard. The Pp index was rated low to excellent for rain-fed agriculture and average to excellent for orchard. Accordingly, the soils can be classified as varying from excellent (PI(S 1)) to low (PIV(N1)) for rain-fed agriculture and from excellent (PI(S1)) to average (PIII(S3)) for orchard. The Pp coefficient revealed that rain-fed agriculture can be improved by 2-6 times and orchard by only two-folds. In conclusion, the lithosols studied had medium natural Fa and Pp with land slope, poor drainage, stoniness (gravel), and low nutrient levels as limitations. The Fa and Pp of these lithosols for rain-fed agriculture and orchard can be improved from moderate to high, with appropriate soil fertilization and conservation measures.
