Influence of the environmental conditions under hail nets on the irrigation and fertilization efficiency in ‘Golden Delicious’ apple trees on replant soils

Optimal irrigation and fertilization management are two of the objectives of precise agriculture. This study aims to analyze the irrigation and fertilization efficiency variability according to the environmental conditions in a young apple orchard. During 2015-2018, three-year-old trees of apple cultivar ‘Golden Delicious’ were grown as a modified slender spindle with regular hand thinning. The treatments – differently managed by drip irrigation and fertilization - were analyzed according to the use of grey hail nets andsites with replant soil. The change in environmental conditions, up to 14% lower light transmittance and 25% lower wind speed and higher soil water content combined with the use of hail nets may have caused alterations in the intensity of vegetative growth and fruit production modifying the water use efficiency and the fertilization management efficiency on replant soils. Appropriate irrigation and fertilizer doses proved to regulate the proportion between vegetative growth and fruit production in apple trees. With decreased intensity in the effect of apple replant disease (ARD), apple trees raise their tolerance to drought stress. It seems that the concentration of applied nutrients becomes more important for the fruit yield than the used irrigation or fertilizer dose alone.