The effect of soil and foliar applications of magnesium fertilisers on yields and quality of vine (Vitis vinifera, L.) grapes

Abstract

A one-year field trial was established with the vine variety Ryzlink vlašský (Riesling italico) to evaluate the effect of spring soil applications and 5x repeated foliar application of magnesium fertilisers on yields and quality of grapes. On light soil of the experimental locality Žabčice (ca 25 km south of Brno) visual symptoms of Mg deficiency on vine leaves had been monitored in the past. The experiment involved 4 treatments: 1) unfertilised control; 2) spring soil application of Kieserite – 20 kg Mg.ha−1; 3) 5x foliar application of a 5% solution of Epso Combitop – Mg, S, Mn, Zn; 11.8 kg Mg.ha−1; 4) 5x foliar applications of a 5% solution of Epso Top – Mg, S; 14.8 kg Mg.ha−1.No significant differences among the treatments were detected in the contents of K (1.40–1.67%) and Ca (1.63–1.91%) in leaves sampled after the applications. After foliar applications the contents of Mg and S significantly increased in treatments 3–4 to 0.42–0.49% and 0.34–0.40 %, respectively compared to treatments 1–2 (0.29–0.30% and 0.22%, respectively). The content of Zn (173–380 mg.kg−1) and Mn (90–551 mg.kg−1) increased significantly in treatment 3 compared to the other treatments. The chlorophyll index did not differ among the treatments. Grape yields (t.ha−1) in treatments 1–4 were the following: 7.04–8.16–7.51–7.26 t.ha−1, respectively. Only the soil-applied treatment 2 differed significantly from the other treatments. The content of sugar (16.5–17.9 °NM), titratable acids (12.78–13.25 g.l−1) and the pH of must (3.02–3.11) did not differ among the treatments.

Keywords

• vine
• magnesium
• soil and foliar application
• yields
• sugar
• acids