Quantitative analysis of vegetative growth in response to nitrogen stress for Vitis vinifera L. cv. Syrah from pot experiments

Abstract

Maintaining grapevine productivity and wine quality with limited inputs (drought, low nitrogen supply) is crucial in Mediterranean areas. Nitrogen, as water, is an important limiting factor in viticulture. But less information is available regarding grapevine responses to nitrogen supply. Even more scarce are the results on the grapevine responses to the combination of these stresses. In absence of such references, decisions regarding management of vineyard are hazardous.

Our first objective was to establish response curves of vegetative growth to N stress. Two-years old Shiraz plants grafted on 110 R (reference material) were grown in pots, submitted to various N stresses under well-watered conditions and managed with conditions as close as possible to those established in vineyards in southern France. Nitrogen supply levels per plant on the entire experiment are : 0g, 0,6g, 1,2g, 2,4g et 12g (field equivalent of these treatments, with the hypothesis of 3500 vine stocks/ ha are 0kg/ha, 25kg/ha, 50kg/ha, 100kg/ha and 500kg/ha).

Vegetative growth meets positively nitrogen supply such as principal shoot length (+60% between N levels of 0g and 2.4g), rate of primary leaf emergence (+50%), rate of secondary leaf emergence (+95%). Nitrogen supply affects also on biomass and nitrogen distribution among principal plant organs. and on leaf area nitrogen content. Quantitative relationships with leaf area nitrogen content were established for all processes studied.

Our study allowed the establishment of SPAD using methodology for nitrogen fertilization management in field. Different levels of fertilization are well detected by SPAD at berry touch and veraison. This study is a first step and goes on considerations of nitrogen stress on reproductive growth.