Based on a field trial, the impact of three different viticultural management strategies on vigour and grapevine physiology of Vitis vinifera cv. Riesling was compared. The vines were planted in 1991 at Geisenheim (Rheingau, Germany) and three different management strategies i.e. integrated (code of good practice), organic (European Union Regulation 834/07 and ECOVIN standard) and biodynamic (European Union Regulation 834/07 and DEMETER standard) were established in 2006.
Even though all treatments received the same level of nutrients and water a decline in vigour, expressed as lateral growth, was observed for the organic and biodynamic treatment during three seasons (2010 to 2012). During dryer conditions (2011) a reduction of physiological activity expressed as stomatal conductance gs, assimilation rate A and transpiration E two weeks after full-bloom and a reduction in pre-dawn water potential at veraison were assessed for the biological treatments. In 2012 under wetter growing conditions neither differences in physiological activity nor in pre-dawn water potential were observed. Therefore changes in physiological activity and pre-dawn water potential are just partially responsible for the reduced vigour in the biological treatments
