MAIZE GROWING UNDER REGULATED WATER DEFICIT IRRIGATION WITHOUT NITROGEN FERTILISATION

The aim of the experiment was to establish the grain productivity of maize grown in the region of Plovdiv (Bulgaria) without fertilisation under water deficit conditions. The experimental work was carried out on Mollic fluvisols (FAO-UNESCO) in the period 2004-2007. The variants set in the field experiment were: 100% of the irrigation rate, 75, 50 and 25% reduction of it and a control variant without irrigation. The yield from the non-irrigated maize was within the range of 4.8-11.8 t/ha (8.7 t/ha in average). The yield varied throughout the years of study, when the water regime got better and at the full irrigation rate it was within the range of 11.3-12.6 t/ha (11.9 t/ha in average). The yield after 25% reduced irrigation was practically the same (11.2-12.6 t/ha). The maize yields obtained under experimental conditions were high and the production itself - ecologically sound.