classification of upper slope soils of a toposequence for rainfed ...

Detai led soi I and land maps of an area approximately 32.592ha, along a representative
topographic location in the University of Agriculture, Abeokuta were produced for effective
land use planning.
The site is underlain by basement complex rock with quartz, schists, coarse grained and fined
grained and gneissis as parent material. Three (3) soil series were identified with soil
properties varying within short distance. Soil textural class ranges from sandyloam to sandy
clayloam with parent gravel ranging from 0.8 - 76.3
Soil reaction is slightly acidic to strong acid (PH 5.46 - 6.32) with moderate to high
phosphorus (10.41 - 57.77)mg/kg and high base saturation (77.95 - n94.34)%. The
coefficient of variability for soil properties ranging from (1.10 - 37.75%) with 18.71% foe
available phosphorus, 16.34 for Ca++ and 37.75 for % gravel, 9.07 % for %OC, 9.48% organic
matter, j.41
for % base saturation
Soil productivity indices for rainfed arable crops (yam, cassava and maize were developed for
the three (3) soil series (Alfisol) in the area. It involved ratings of relevant soil characteristics
and using the ratings to calculate soil productivity index and soil fertility index. Actual
productivity index (p) is the product of the rating for soil depth (d), texture (t), slopes (s), soil
fertility index (f) and annual rainfall (w). The soil fertility index (f) is the product of rating
for nutrients (Pn), organic matter ( I' ), base saturation (n), nature of clay minerals (e) and
mineral reserve (m). Potential productivity index (PI) is the product of soil depth (d), texture