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Effect of various potassium-calcium ratios on cation nutrition of grape grown hydroponically

Garcia, M., Daverede, C., Gallego, P., Toumi, M.
Journal of plant nutrition 1999 v.22 no.3 pp. 417-425
Vitis vinifera, potassium, calcium, cations, hydroponics, nutrient-nutrient interactions, nutrient solutions, nutrient availability, nutrient deficiencies, nutrient content, leaves, petioles
The effect of potassium (K)-calcium (Ca) ratios on the cation nutrition of Vitis vinifera L. cv. Negrette was investigated on grafted vines grown hydroponically to gain a deeper insight into the origin of the lack of acidity of some wines. Four nutrient solution solutions were investigated for long duration experiments: a balance K-Ca nutrient solution K=3.9 meq L-1; Ca=4.8 meq L-1)used as a reference, a low K(K=0.3 meq L-1; ca=8.4 meq L-1) and a high K(K=7.1 meq L-1; ca=1.6 meq L-1) nutrient solutions. Besides, the reference nutrient solution was enriched with Ca (K=3.9 meq L-1; Ca=13.8 meq L-1) so as to simulate the possible effects of liming. The experiments showed that, in spite of low K requirements, the high K storage capacity of cultivar Negrette might account for the low acidity of the wines. However, a strong Ca-K antagonism was characterized: the Ca enrichment of the reference nutrient solution resulted in a 30% decrease in the K concentration of leaf blades and petioles. Liming can thus limit K uptake by the plant and contribute to increased acidity of the wines issued from cultivars grown in acid soils.