SUITABILITY EVALUATION OF RAINFED RICE (ORYZA SATIVA) IN FLOOD PLAIN OF SOUTHERN GUINEA SAVANNAH ZONE OF NIGERIA

Abstract

The flood plain of Awe in Southern Guinea Savannah Zone of Nigeria was studied for rice production. The physical, morphological and chemical properties of the soils were matched with the requirements of the rice production and the overall suitability rating of the soils was obtained using limitation method. The soils were deep (101cm – 170cm) and well drained, poorly to very poorly drained. The soils were fine textured and strongly to moderately acidic and slightly alkaline in reaction (pH 5.10 – 7.15). The percentage sand fraction ranged from 44.8% to 83.1%; silt 5.4% to 9.4% and clay 9.4% to 46.7%. They had low to moderate organic carbon (0.41% to 3.52%); total N (0.04% to 0.11%); available P (1.64mglkg^-1 to 3.72mg/kg^-1), total exchangeable bases (2.85cmol/kg^-1 to 7.97cmol/kg^-1), CEC (4.10cmol/kg^-1 to 7.98cmol/kg^-1), base saturation (65% to 97.5%) and Fe²⁺ (1.10 to 2.11). Soils of the three flood levels (toeslope or deep swamp, medium or lower slope, levee or shallow swamp) were rated highly to suitable (S₁₎ because of the soils ability to retain water during the growth period with the favourable physical and chemical characteristics such as climate, slope, water levels, pH and texture. Management practices such as organic matter incorporation, liming to increase soil pH, fertilizer application and appropriate time of planting are hereby recommended for increased rice production in the mapping units that are not highly suitable for rice production in the study area.