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

143Table 1. Grain yield of maize and soybean and fallow biomass in 2003.Crop Grain yield (kg ha -1 )TGx 1448-2E 1533Samsoy-2 1536Maize 2165Fallow 2877 ++Above-ground biomass.semi-micro Kjeldahl digestion (Bremner 1965). Exchangeable cationswere displaced with 1.0 M NH 4OAc. Exchangeable potassium (K) wasdetermined by fl ame photometry, and calcium (Ca) and magnesium(Mg) by atomic absorption spectrophotometry. Exchangeable aciditywas determined by extracting with 1.0 M KCl and titrating with 0.1M NaOH and the CEC of the soils were estimated by the summationof exchangeable cations and acidity (Rhoades 1986; Agbenin andGoladi 1997).Statistical analysesAll variables collected were subjected to analyses of variance (ANOVA)using the PROC GLM procedure (SAS 1989). Where there was asignifi cant effect of the treatments or their interactions, the LeastSignifi cant Difference (LSD) was used to establish differences betweenmeans at P = 0.05.Results and Discussion2003 ExperimentFallow biomass and grain yield of maize and soybean. The differencebetween the grain yield of Samsoy-2 and that of TGx 1448–2E wassmall and not statistically signifi cant (Table 1).Olufajo et al. (1988) reported that N application stimulates plantgrowth by supplying the seedling with N before initiation of nodulesand onset of fi xation especially if nodule development is delayed andboth seed and soil nitrogen cannot meet the plant’s N requirement.This initial increase in seedling vigour is often accompanied by anincrease in grain yield. Maize grain yield was 2165 kg ha -1 expressedon sun-dried basis while all fallow plots produced biomass of 2877 kgha -1 also expressed on sun-dried basis.2004 ExperimentSoil Chemical Properties. The F ratios from the analyses of variancefor soil chemical properties are presented in Table 2. Rotation and Nfertilizer had signifi cant effects on soil pH, organic carbon (OC), totalN, exchangeable Ca, Mg, K, CEC and of rotation × fertilizer interaction