THE DYNAMICS OF PHOTOSYNTHETIC PIGMENTS IN WINTER WHEAT LEAVES WHEN USING NITROGEN FERTILISERS

Abstract

The paper investigates the effect of nitrogen fertilisers on the amount of photosynthetic pigments in winter wheat leaves. The research was carried out in the period between 2012 and 2013 at the Experimental Station of Aleksandras Stulginskis University in carbonate shallow gleyic leached soil, (Calc(ar)i-Epihypogleyic Luvisol). The object of investigation: winter wheat cultivars ‘Zentos’ and ‘Ada’. Granular superphosphate (P60) and potassium chloride (K60) fertilisers were spread during sowing, while amonium nitrate (N60) was used in tillering time (BBCH 23–25), after the vegetative growth had resumed. Additionally, the plants were treated with foliar fertiliser urea solution: N30, N40 at booting stage (BBCH 34–36) and N15, N30 at milk ripening stage (BBCH 71–74). After the analysis of the data, it was established that additional fertilization with N30 and N40 fertiliser application rates at later stages of plant development stimulated the accumulation of photosynthetic pigments and prolonged the period of active photosynthesis. Irrespective of treatment with nitrogen fertilisers, genetic properties of the cultivar also had influence on the accumulation of the pigments. Wheat cultivar ‘Zentos’ tended to accumulate larger amounts of pigments. The highest amounts of pigments were found at the beginning of milk ripening stage before additional treatment with N15, N30 fertiliser application rates.