Transpiration and nitrogen uptake of maize varieties using Szlovak-type of weighing lysimeters

N-uptake was studied in weighing lysimeters in a 60 000 plants per hectare plant stand. Five maize hybrids were examined for transpiration, water utilization, N-uptake and its distribution in plants. After harvest the plant parts were separated and dried until constant weight was achieved. Though hybrid Pi RSC 3732 transpired most water, because of high dry matter yield, its water utilization was also the most favourable. Among plant parts the grain contained most N. Its values were between 1.7 and 4.13 g. The best physiological and agronomic efficiency was calculated for Pi RSC 3732. The hybrid Sabrina 3707 transpired the most water (20.19 kg) per I g of N absorbed. The amount of N -uptake calculated per 1 kg of transpired water was between 49.72 and 82.93 mg. There were no significant differences between the NIP ratios of the whole plants and grain. The lowest NIP ratios of the whole plants and grain were at hybrid Pi RSC 3732 (4.18 and 4.81) and the highest at hybrid Szentesi 212 (6.10 and 5.88).