Abstract

Nutrient deficiencies and imbalances are the main constraints of crop production in Nigeria and thus, assessing the suitability of the lands for agricultural production, especially in developing countries to boost crop yield is very urgent and timely. The study is aimed at examining the suitability assessment of soil for cassava production in Southern Cross River State, Nigeria. Soil samples were randomly collected from nine peasant cultivated cassava farms in each of 16 coastal and 16 hinterland areas. Four transects, each 7.0 km long, were established in the eastern, western, northern and southern directions due to break in slope and creeks of the land terrain. Nine soil profiles comprising two in each direction and the starting point were selected along the transect. For each of the profile, a sample of soil was collected at each master horizon and were analysed for physico-chemical properties. In addition, ten cassava plots of 10 m² were randomly selected from an area of 10,000 m² for cassava yield analysis. The cassava yield parameter was correlated with soil properties using Pearson’s moment correlation and multiple regression analysis. The suitability assessment of the soil was carried out by comparing the soil requirement for cassava production as outlined by Howler. The soil properties (top and subsoils) in the hinterland were sand (886 ± 3.8 and 819 ± 5.0), silt (46 ± 2.0 and 64 ± 2.0), clay (754 ± 4.6 and 117 ± 3.6), organic matter (130 ± 1.9 and 29 ± 3.6) and electrical conductivity (0.054 ± 0.02 dsm^-1 and 0.023 ± 0.02 dsm^-1). In the coastal area these were sand (337 ± 19.8 and 290 ± 15.3), silt (282 ± 7.0 and 329 ± 4.4), clay (381 ± 14.8 and 381 ± 12.6), organic matter (38 ± 0.6 and 29 ± 0.4) and electrical conductivity (15.4 ± 9.3 dsm^-1 and 18.7 ± 9.1 dsm^-1). The mean cassava yield in the hinterland (49.71 ton/ha) was significantly higher than in the coastal area (29.11 ton/ha) at (P<0.05). The results further revealed that the hinterland (Akpabuyo) site is very good for cassava production with a suitability index (S.I.) of 64.29% than the coastal (Bakassi) site with (S.I.) of 21.43%. In the hinterland area, 89% of changes in cassava tuber-yield was explained by soil properties and 54% of changes in cassava tuber-yield was influenced by the combination of soil properties in the coastal (Bakassi) site. An intervention is needed for appropriate management strategy to boost cassava production in the coastal area.

Key word: Suitability assessment, cassava yield, coastal and hinterland soils, soil properties.