First experiences with grapevine (Vitis vinifera L.) fertigation in Hungary

The overall aim of the study was to develop a fertigation method for improving grape production, fruit and wine quality and vine cold hardiness. Preliminary results of the study are presented in this paper. Different irrigation and fertigation treatments were applied in a 5 years old Chardonnay vineyard in the Eger wine district in Hungary. 20-25 % yield surplus was obtained for irrigated and fertigated vines comparing to control (non irrigated) plants with only a slight decrease in must sugar content and a desirable amount of must titratable acidity. No differences occurred between irrigation and fertigation treatments in 1997. Soil and plant nutritional analysis showed that phosphorous and potassium concentration decreased below optimal values in control (non-irrigated) plants, but there was no significant difference between irrigated and fertigated vines. It is supposed that the limiting factor for nutrient uptake of the vines in the vineyard was insufficient water supply, rather than lack of nutrients in the soil under the given circumstances. Irrigated and fertigated vines -at the whole plant level- gave higher photosynthetic production than control vines, because of a larger leaf surface due to:enhanced vigour. The water status of the non-irrigated control plants was close to the drought limit from the beginning of August. This effect and possibly better transport conditions for nutrients resulted in increased yield for treated plants. Irrigation and fertigation slightly retarded (by about 2 months) cane ripening, but at the beginning of deep dormancy, the maturity of canes in different treatments reached the same level. Frost hardiness of buds was not decreased by irrigation, and seemed even improved (especially in fertigated vines) under the circumstances of 1997. Aroma analysis of juices showed (1996 vintage, only irrigation treatments were applied and not fertigation) that irrigation caused no essential reduction in volatile components of the must. The relative amount of some components (hexanal, 2-hexanal and benzene-ethanol) was lower in the irrigated samples. This effect was less pronounced in wines. A sensory evaluating panel found no significant qualitative differences between wines.