Wpływ zróżnicowanego nawożenia azotem na wskaźnik powierzchni liści (LAI), średni kąt nachylenia liści (MTA) i plon wybranych odmian pszenicy jarej

The study was carried out in the years 2001–2003 in the fields of the Experimental Station, Institute of Cultivation, Fertilization and Soil Science at Jelcz-Laskowice. The experiments were set up on soil of very good rye complex with the split-block method in two replications. There were applied two doses of nitrogen fertilization. The first general dose was applied before sowing, while the additional one (40 kg N) at shooting stage. Leaf area index (LAI) and mean tip angle (MTA) were determined with use of a LAI-2000 meter (LI-COR, USA) at the beginning of the heading stage in four replications. The study aimed at assessing the influence of differentiated nitrogen fertilization on the yielding of crops and selected indices of canopy architecture (LAI, MTA) with five spring wheat cultivars. The cultivars belonged to three groups of technological value: selective, qualitative and bread. The yields of spring wheat were found to have been significantly influenced by weather conditions, particularly in the third year of the study. Long-lasting drought during the vegetation period brought about a decisive decrease in the yields after application of a higher nitrogen dose. The leaf area index was significantly differentiated according to cultivars, fertilization and years. The highest LAI index was noted in Opatka cultivar grown on an increased dose of nitrogen fertilization in the second year of the study. The largest mean tip angle (MTA) was observed in the Zebra cultivar in the first year of the study