Studies on the effect of N fertilisation on the growth of maize ( Zea mays L.) hybrids I. Dynamics of dry matter accumulation in whole plants and plant organs
Investigations on the process of dry matter accumulation over time could contribute to improvements in the N fertiliser utilisation of maize hybrids. In 2001 and 2002 the effect of four N fertiliser rates (0, 80, 160, 240 kg ha −1 ) on the growth and productivity of three maize hybrids with different vegetation periods [Mv TC 272 (FAO 280), Mv 355 SC (FAO 390) and Maraton SC (FAO 450)] was studied in an almost 50-year-old long-term experiment involving continuous maize, as a stress environment. The experiment was set up in Martonvásár on chernozem soil with forest residues in a split-plot design with four replications, with the N treatments in the main plots and the maize hybrids in the subplots. Plant samples for yield analysis were taken at 14-day intervals on 8 occasions a year. The dynamics of dry matter accumulation in the whole plants and in various plant organs (stalk, leaf, grain), and that of leaf area, differed significantly between N treatments and hybrids. The effect of mineral N fertilisation was significant from the 4–6-leaf stage and the differences between hybrids from the flowering stage. Both the dry matter yield and the leaf area were greatest in the N 160 treatment. The greatest difference in the pattern of N fertiliser reactions over time was detected between the pre-flowering and post-flowering stages. The maize grain yield was greatest in the N 160 treatment, exhibiting the following values (t ha −1 ) in the individual N treatments: N 0 : 4.907, N 80 : 7.872, N 160 : 8.921, N 240 : 8.770. The results indicate that the dynamics of dry matter accumulation in the whole maize plant and in various plant organs could further our understanding of the N fertiliser responses of maize hybrids.