Long-term effect of crop production factors on the yield and yield stability of maize (zea mays L.) in different years

Abstract

The effects of five crop production factors (tillage, fertilisation, plant density, variety, weed control) on the yield and yield stability of maize were examined in Martonvásár (HU) in a polyfactorial experiment and in separate long-term experiments on the effects of Nfertilisation, sowing date and plant density. In the polyfactorial experiment the five crop production factors contributed to the increase in maize yield in the following ratios (%): fertilisation 30.6, variety 32.6, plant density 20.2, weed control 14.2, soil cultivation 2.4. In the N fertilisation, sowing date and plant density experiments the effects of the treatments on the maize yield were examined separately for dry and wet years.Averaged over 40 years, the yields in the long-term N fertilisation experiment were 2.422 t ha−1 lower in the dry years than in the wet years (5.170 vs. 7.592 t ha−1). The optimum N rate was 160 kg ha−1. In the sowing date experiment the yield was 2.533 t ha−1 lower in the dry years than in the wet years (6.54 vs. 9.093 t ha−1), averaged over 19 years. In dry years the yield was highest for the early and optimum sowing dates, and in wet years for the optimum sowing date. Sowing at dates other than the optimum caused reductions in N fertiliser efficiency. Averaged over 22 years, the optimum plant density was 80,000 plants ha−1 in wet years and 50,000 plants ha−1 in dry years. The yield was most stable at a plant density of 60,000 plants ha−1. The clarification of year effects is particularly important in relation to the possible effects of climate change.