Influence of soil reaction on phosphorus, potassium, calcium and magnesium dynamics in grapevine was studied on the variety Sauvignon Blanc in 2007, in the Plešivica wine-growing region. Investigations were conducted on three vitisol subtypes: dystric cambisol (pHKCl 3.73-3.76), pseudogley (pHKCl 4.67-4.69) and rendzina on marl (pHKCl 7.21-7.27). To establish the amount and dynamics of P, K, Ca and Mg in plant material, leaf samples were taken three times during the growing period: at the flowering and veraison stages and at the end of the growing period. At all sampling times, significantly higher leaf contents of P, Ca and Mg were found on alkaline soil compared to acid soils, while differences in K levels were not statistically significant. Differences in P contents may be explained by better solubility and thereby better availability of P from Ca-phosphates compared to Al, Mn and Fe-phosphates in acid soils. In addition, the cation ratio K/(Ca+Mg) that has a significant influence on grape quality, was also determined in leaves. Compared to optimal values (0.30–0.40), the least favourable ratio K/ (Ca+Mg) was recorded at flowering on acid soils (0.38–0.77) and at harvest on calcareous soil (0.12–0.27). Differences in the content of sugar and total acids in must indicate a positive correlation between leaf contents of P, Ca and Mg and sugar content of must, and a negative correlation between leaf contents of P, Ca and Mg and the total acid content of must.

grapevine; soil reaction; leaf; must

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia