Studies on the effect of N fertilisation on the growth of maize ( Zea mays L.) hybrids II. Plant growth analysis and growth parameters

Abstract

The use of growth analysis and growth parameters could make an important contribution to improving the utilisation of N fertiliser by 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 was studied in a long-term experiment involving continuous maize, representing a stress environment, set up in Martonvásár on chernozem soil with forest residues almost 50 years ago. Each year eight samples were taken at 14-day intervals for the destructive method of growth analysis. N fertiliser was found to have a significant effect on the growth parameters of individual plants (RGR, NAR, LAR) in both the vegetative and generative stages of growth, up to N rates of 80 and 160 kg ha −1 , respectively. The value of RGR increased until the N 160 treatment and that of NAR until N 80 , while LAR declined significantly in response to N fertilisation. RLGR was enhanced by N fertiliser up to a rate of N 80 , and all the N treatments reduced the extent of leaf withering. Among the growth parameters of the canopy, the values of CGR and HI rose significantly up to N 160 and that of LAI max up to N 80 . The cumulative values of LAD and BMD were highest in the N 160 treatment. All the growth parameters increased as the vegetation period of the hybrids lengthened, and all reflected the year effect. Compared to the highest N rate, N stress of 29–38% was calculated for the control treatment. On average, N fertilisation resulted in a 6–27% relative decline in LAI after flowering.