The effect of selected fertilizers foliar aplication on sunflower production | Účinek listové aplikace vybraných hnojiv na produkci slunečnice roční

Plant nutrition based on the rational use of fertilisers is important in sustainable production of sunflower (Helianthus annuus L.) as a source crop for safety food and feed, oil and decorative, industrial and bioenergetic purposes. A good supply of nutrients in the soil is one of the basic prerequisites of economically effective yields of high quality. In experiments established in 2008-2010 we studied the combined effect of foliar fertilisers Borosan Forte, Fertigreen Kombi, SK sol and Mikrokomplex Cu-Mn-Zn on the growth and development of sunflower. The resulting effect of the fertiliser Borosan Forte (2 t per ha) applied in the stage of 4th true leaf was a higher content of B in the plant matter and increased dry matter weight of the plant. The application of Fertigreen Kombi (4 t per ha) in combination with Mikrokomplexem Cu-Mn-Zn (1 t per ha) and the application ofSK sol (3 t per ha) together with Mikrokomplex Cu-Mn-Zn (1 t per ha) applied in the beginning of elongation growth after supplementary application of the fertiliser Borosan Forte increased the biomass production of the plant. Foliar nutrition also increased the content of macro elements in the dry matter of leaves, most of all the amount of N, P and K. Supplementary fertilisation with the fertiliser SK sol also considerably increased the content of sulphur (26.1% rel. in leaves and as much as 68.7% rel. in the stems). Just as the effect of the year the application of tested combinations of fertilisers had a statistically significant effect on sunflower yields. Supplementary fertilisation with Borosan Forte in combination with Fertigreen Kombi and Mikrokomplex Cu-Mn-Zn had the greatest effect on yields which increased by 12%. Supplementary fertilisation with only Borosan Forte significantly increased yields by 9.7%. Foliar applications did not affect the oil content of achenes. Due to the increased yields and stagnation in the oil content the resulting effect of fertiliser application was a statistically significant increase in oil production (t-hsr1); in combination with SK sol by as much as 11.8%. Foliar application of fertilisers had no effect on the content ofoleicacid.