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IMPACTS OF NITROGEN FERTILISATION AMOUNT AND TIMING ON GRAPEVINE NITROGEN AND CARBON STATUS IN HIGH YIELDING VINEYARDS OF SOUTH OF FRANCE EFFETS DE LA DOSE ET DE LA PERIODE DE FERTILISATION AZOTEE SUR LES STATUTS AZOTE ET CARBONE DE LA VIGNE DANS LES VIGNOBLES A FORT RENDEMENT DU SUD DE LA FRANCE
PELLEGRINO, Anne1*; METAY, Aurélie2; ESTIVAL, Paul3; HAMARD, Philippe4; ROLLAND, Gaelle4; DAUZAT, Myriam4; LEPORATTI, Romain4; PEYROT, Gérard5; RUETSCH, Gabriel3 1 Montpellier SupAgro, UMR LEPSE - Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, 2 Place Viala, F-34060 Montpellier, France. 2Montpellier SupAgro, UMR SYSTEM - Fonctionnement et conduite des systèmes de culture tropicaux et méditerranéens, 2 Place Viala, F-34060 Montpellier, France. 3Foncalieu – Lieudit Corneille, 11290 Arzens, France. 4INRA, UMR LEPSE - Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, 2 Place Viala, F-34060 Montpellier, France. 5Les Celliers du nouveau monde - 10 rue de la Paix, 11700 Puichéric, France *Corresponding author: anne.pellegrino@supagro.fr
Abstract: Maintaining grapevine productivity with limited inputs is crucial in Mediterranean areas. Apart from water, nitrogen supply is a major limiting factor for grapevine growth and metabolism. The present study focused on the nitrogen nutrition of a fertirrigated Sauvignon Blanc vineyard in the Mediterranean region, producing high yields (15 t/ha) and benefiting from a reduced post-harvesting period. The impact of nitrogen fertilization amount (0U, 40U and 120U) and timing (8-10 open leaves, mid-bloom, midveraison) on grapevine growth, yield components, nitrogen- and carbon- metabolisms were analyzed over 3 consecutive years and compared to a non-irrigated and unfertilized control. Leaf nitrogen status was moderate to high for all treatments, indicating an important buffering effect of the soil. Higher or earlier nitrogen supply slightly increased the number of bunches and final yield for the most fruitful vintages only. However, bunches sizes and the percentage of biomass allocations toward the aboveground organs were not impacted by the nitrogen treatments. In addition, the photosynthesis rate over the four years was similar among the treatments. A nitrogen nutrition indicator measured from handheld sensors (SPAD, N-tester) at different periods of the cropping season was proved to be effective to simply compare the different fertilization strategies. This study highlighted the need for a better assessment of nitrogen requirements in fertirrigated vineyards of South of France to optimize plant functioning while avoiding environmental losses. Simple using-tools were shown to be relevant for that purpose.
Keywords: Vitis vinifera L., nitrogen nutrition, yield, vegetative development, photosynthesis
Abstract: Maintaining grapevine productivity with limited inputs is crucial in Mediterranean areas. Apart from water, nitrogen supply is a major limiting factor for grapevine growth and metabolism. The present study focused on the nitrogen nutrition of a fertirrigated Sauvignon Blanc vineyard in the Mediterranean region, producing high yields (15 t/ha) and benefiting from a reduced post-harvesting period. The impact of nitrogen fertilization amount (0U, 40U and 120U) and timing (8-10 open leaves, mid-bloom, midveraison) on grapevine growth, yield components, nitrogen- and carbon- metabolisms were analyzed over 3 consecutive years and compared to a non-irrigated and unfertilized control. Leaf nitrogen status was moderate to high for all treatments, indicating an important buffering effect of the soil. Higher or earlier nitrogen supply slightly increased the number of bunches and final yield for the most fruitful vintages only. However, bunches sizes and the percentage of biomass allocations toward the aboveground organs were not impacted by the nitrogen treatments. In addition, the photosynthesis rate over the four years was similar among the treatments. A nitrogen nutrition indicator measured from handheld sensors (SPAD, N-tester) at different periods of the cropping season was proved to be effective to simply compare the different fertilization strategies. This study highlighted the need for a better assessment of nitrogen requirements in fertirrigated vineyards of South of France to optimize plant functioning while avoiding environmental losses. Simple using-tools were shown to be relevant for that purpose.
Keywords: Vitis vinifera L., nitrogen nutrition, yield, vegetative development, photosynthesis