THE INFLUENCE OF STRESS FACTORS ON SPRING BARLEY YIELD PUBLISHEDEva Candráková, Nora POLLÁKOVÁ, Eva HANÁČKOVÁ
Abstract: Spring barley malting varieties (Nitran, Ezer and Poprad) and their response to environmental conditions, year and fertilization were investigated in the field experiment of Slovak University of Agriculture enterprise in Oponice during years 2005 - 2007. Altitude of the area is 168 m above sea level, average annual precipitation is 607 mm, and temperature 9.5 °C. Main soil type was classified as Haplic Luvisol on loess with loamy texture. Treatments of fertilization were as follows: 1. control - without fertilization, 2. LAV (ammonium nitrate with limestone) 20 kg ha -1 of net nitrogen, 3. LAV for grain yield level of 5 t ha -1 applied at the end of shooting stage, 4. DAM 390 (ammonium nitrate with urea) in rate 20 kg ha -1 of net nutrient N applied at the end of shooting stage. Rates of fertilizers were calculated on the base of agrochemical soil analyses, which were done from samples collected before sowing and at the beginning of shooting stage from depth of 0.3 and 0.6 m. The effect of moisture and temperature on grain yield was expressed by the value of internal energy (ΔU). Changes of ∆U in the non-vegetation period and in the critical growth stages of spring barley, and the influence of observed parameters on the yield formation in years with Y max and Y min were evaluated for the analysis of the thermo dynamical characteristics. Negative value of internal energy expresses the dominant effect of temperature beyond moisture and acts positively on grain yield. Positive ∆U values act opposite. The highest grain yields (Y max 7.94 t ha -1 ) were achieved in year 2005 and the lowest in year 2007 (Y min 4.28 t ha -1 ), what demonstrated the statistically significant influence of year, varieties and fertilization. Despite the fertilization by nitrogen promoted increasing of grain yield, but the effect of year was stronger.
spring barley, varieties, fertilization, water, temperature, yield