The effect of amino acids on nitrogen, phosphorus and potassium changes in spring barley under the conditions of water deficit

Small plot experiments were conducted on an Endocalcaric Endohypogleyic Luvisol in Aleksandras Stulginskis University to determine the effect of different concentrations of amino acids on the dynamics of nitrogen, phosphorus and potassium in spring barley leaves and on grain productivity under the water deficit conditions. The following experimental design was used: factor A different concentrations of amino acid solutions: the control (unsprayed), sprayed with water, sprayed with 0.5, 1.0, 1.5, 1.5 % with microelements and 2.0% amino acid solutions; factor B - time of fertilization with the amino acids: BBCH 21-23 and 26-29 growth stages. Topsoil moisture content decreased from 14.5% to 8.7% during the BBCH 21-49 stages and thus it was considered as water deficiency conditions. The amino acid solutions of different concentrations, used for spring barley fertilization under the water deficiency conditions during the BBCH 21-23 or 26-29 stages, significantly increased the nitrogen, phosphorus and potassium content in the plants during the BBCH 26-29 and 32-35 stages in comparison to the control plants that were not sprayed with water. In many cases, the water spray stimulated nitrogen uptake to the same extent as amino acids application. Having analysed the effect of spring barley fertilization with the amino acids, it was found that the content of nitrogen did not reach the optimal level in the leaves of plants. However, the content of phosphorus reached the minimal limit of the optimal content at the BBCH 26-29 stage. A significant yield increase (0.15-0.47 t ha(-1)) was obtained when the spring barley had been fertilized with the 1.0% concentration of amino acids solution during the BBCH 21-23 stage.