Influence of temperature and moisture conditions of locality on the yield formation of sunflower (Helianthus annuus L.)

Abstract

Field polyfactorial experiments were realized on fields of the Agricultural Co-operative in Nitrianska Blatnica in years 2007-2009. Experimental field is located in the maize production area (climatic region: warm; climatic sub region dry; climatic zone: warm, dry with mild winter and long sunshine) in altitude 250 m above sea level, with brown soil. We observed the influence of both temperature and moisture conditions of experimental area on sunflower yield of achenes (conventional, medium-late hybrids: NK Brio, NK Armoni). Preceding crop of sunflower (Helianthus annuus L.) every experimental year was wheat (Triticum aestivum L.). Technological system of sunflower cultivation was realized in accordance with conventional technology of cultivation. The basic fertilization was made by balance method on the base of agrochemical soil analysis for expected yield 3 t.ha-1. The meteorological data were got out from agrometeorological station of the Central Controlling and Testing Institute in Agriculture in Vel'ke Ripňany. During every experimental year the change of inner energy (ΔU) was evaluated for thermodynamic characteristic analysis (security of the temperature and moisture) and the impact of changes on yield forming with maximal yield (Ymaxin 2008) and minimal yield (Ymin in 2009). Achieved value of yield from thermal and precipitation energy introduces concrete energy amount, which is available in given period for concrete height of yield. From the results follow, the sunflower has got critical thermodynamic phase in the period of months from July to August. For the yield formation is requirement, that input power of precipitation prevailed over the thermal during moths July to August. Achieved results confirmed statistically high significant dependence of the yield on weather conditions and for high annual variations in climatic characteristics the consideration is needed about potential changes some agrotechnological measures of technological system of sunflower cultivation.