EFFECT OF FOLIAR APPLICATION OF AMINO ACIDS ON THE PHOTOSYNTHETIC INDICATORS AND YIELD OF WINTER WHEAT

Experiments involving a winter wheat (Triticum aestivum L.) variety 'Sirvinta 1' were conducted at the Experimental Station of the Aleksandras Stulginskis University during the period 2006-2009 in limnoglacional silty loam on morainne clay loam Cal(ca) ri-Endohypogleyic Luvisol. Winter crops were grown on the background of N150P90K90 mineral fertilization and were additionally foliar-fertilized with amide nitrogen fertilizer, containing different concentrations of amino acids (0.5 %-3.0 %), at a winter wheat booting, heading and milk maturity stages. Experimental evidence showed that solutions with different amino acids concentrations applied for winter wheat fertilization at booting, heading and milk maturity stages increased plant photosynthetic indicators. Chlorophyll a to b ratio in winter wheat leaves significantly increased having applied 0.5-2.5 % amino acids solutions at booting and at milk maturity stages. Plants fertilized with amino acids solutions at booting stage had a possibility to form larger assimilating leaf area. Winter wheat grain yield significantly increased (0.27-0.4 t ha(-1)) under the effect of amino acids. The highest yield increases were obtained having applied amino acids at booting and heading growth stages. The statistical data analysis (x(extr).) evidenced that the highest yield and its quality would be attained with foliar feeding of winter wheat with amino acids fertilizers: at booting stage with 2.4 %, at heading stage with 1.47 %, and milk maturity stage with 1.39 % amino acids solution.