EFFECT OF SOWING DATE AND N FERTILISATION ON THE YIELD AND YIELD STABILITY OF MAIZE (Zea mays L.) HYBRIDS IN A LONG-TERM EXPERIMENT

摘要

The effect of sowing date, N fertilisation and genotype on the grain yield and yield stability of maize was studied between 1991 and 2006 in a long-term N fertilisation experiment set up on chernozem soil in Martonvasar, Hungary. The N treatments (0, 60, 120, 180 and 240 kg ha(-1)) represented the main plot of the three-factor, split-split-plot experiment, with the sowing date (early, optimum, late, very late) in the sub-plots and hybrids from different maturity groups in the sub-sub-plots. The highest yields were obtained for the early and optimum sowing dates (8.712 and 8.706 t ha(-1)). Compared with the optimum sowing date, a delay of ten or twenty days led to yield losses of 5% and 12.5%, respectively. In the late and very late sowings and in years with unfavourable weather conditions, yield increments were only observed up to an N rate of 60 kg ha(-1), while in the early and optimum sowings and in favourable years yield increments were significant up to 120 kg ha(-1) N. Yield stability was smallest in the early and very late sowings, in the control and for high N rates, and in the early and late maturity hybrids. It can be concluded that high yields and yield stability are not mutually exclusive.