Demand-Driven Technologies for Sustainable Maize ... - IITA

57Table 2. Soil characteristics of Nkoemvone, Cameroon, at the beginningof the field trials, 2003.Characteristic 0-20 cm 20-40 cm MeansPH (water)Ca cmol(+) /kgMg cmol(+) /kgK cmol(+) /kgNa cmol(+) /kgAl cmol(+) /kgMn cmol(+) /kgH + cmol(+) /kgCEC cmol(+) /kgT/SP (olsen)4.330.430.220.110.212.090.040.454.3122.2295.004.520.250.090.070.250.040.020.353.9916.6938.004.430.340.150.090.232.060.030.404.1518.4566.50Table 3. Mean values for grain yield, number of days to silking (DTS),anthesis-silking interval (ASI) and plant height for 105 F1 hybridsevaluated under acid soil (O) and non-acid soil (T) conditions inCameroon, 2003 and 2004.Year Grain yield(t/ha)DTS(days)ASI(days)Plant ht(cm)O T % R + O T O T O T20032004Mean1.441.301.374.173.073.6265.557.762.2697170636464455323132129131192184188+%R = Percent reduction of O relative to T.Results and DiscussionResults of Nkoemvone soil analysis at the beginning of the trials arepresented in Table 2. The pH of the soil was less than 5.0 (pH = 4.43)and Al 3+ was at toxic level. Therefore, the soil acidity was mainly dueto aluminium.Means for measured traits presented in Table 3 revealed that,relative to the non-acid soil, grain yield of the hybrids on acid soil wasreduced by about 62%, DTS was lengthened by 6 days, ASI increasedby 2 days and plant height decreased by 31%. These results confi rmearlier reports that soil acidity is a major constraint to maize production(Borrero et al. 1995; Duque Vargas et al. 1994).Under both soil conditions, but particularly under the non-acidsoil condition, grain yield was lower in 2004 than 2003. A dry spellof about 10 days that occurred during the 2004 cropping season