THE EFFECT OF LIMING ON MAIZE YIELD AND SOIL PROPERTIES IN SOUTHERN NIGERIA

Effects of four rates of lime applications to maize grown in 12 strongly acidic soils of southern Nigeria belonging to Ultisol and Inceptisol orders were studied under greenhouse conditions. Five of these soils (Al saturation, 26%-33%; Ca saturation, 3%-16%) showed marked responses to lime with % relative yield (percentage of maximum yield) ranging from 5 to 73, 2 soils (Al saturation, 1% and 5%; Ca saturation, 52% and 59%) showed no response (about 95% relative yield) and the remaining 5 soils (Al saturation, 15%-28%; Ca saturation, 10%-31%) showed marginal responses (79% to 90% relative yield). Percent relative yield was highly correlated with initial soil values of % Al saturation (r = 0.923), 0.02M CaCl2 soluble Al (r = 0.906), % Ca saturation (r = 0.806) and exchangeable Ca (r = 0.729) and poorly correlated with soil pH (r = 0.559). Overall, Al saturation, soluble Al, Ca saturation and exchangeable Ca values corresponding to 90% relative yield were 27%, 13 mg/L, 21% and 0.7 cmol(+)kg, respectively. On an individual soil basis, near maximum yield was obtained when liming reduced the soil Al saturation to 25% and increased Ca saturation to 28%. No increase in yields was obtained by liming beyond pH 5.5.