Foliar fertilization with molybdenum in sunflower (Helianthus annuus L.)

The objective of the vegetation experiment established in 2008-2011 was to explore the effect of the time and dose of foliar molybdenum (Mo) application on the yield and quality of sunflower. Four treatments were established in the experiment: (1) control - not fertilised with Mo; (2) application of 125 g Mo/ha in the growing stage of 4 developed leaves (V-4); (3) application of 125 g Mo/ha at the beginning of elongation growth (R-1), and (4) split rate of Mo application of 62 g Mo/ha at stage V-4 (4 developed leaves) and 62 g Mo/ha at stage R-1 (terminal bud forms). Foliar application of molybdenum increased the biomass production of sunflower plants and its content in dry matter. A statistically significant effect of molybdenum foliar application on sunflower yields was found. Foliar application of Mo up to a dose of 125 g Mo/ha at the beginning of vegetation (stage V-4) and developmental stage R-1 increased yields of achenes. The relative increase in the oil content after foliar nutrition was not significant and ranged between 1.4% and 2.6%. Oil production increased due to increased yields and stabilised oil content. Foliar application of molybdenum had no effect on the content of oleic acid.