STUDIES ON THE EFFECT OF N FERTILISATION ON THE GROWTH OF MAIZE (Zea mays L.) HYBRIDS II. PLANT GROWTH ANALYSIS AND GROWTH PARAMETERS

摘要

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)) oil 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 Martonvasar 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, tip 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.