Evaluation et analyse de la variabilité spatiale de la mortalité des ceps dans un vignoble languedocien à partir de photographies aériennes à haute résolution

National audienc

Coffee and vineyard agroforestry: what lessons on agroforestry with perennial plants can be shared?

International audienceCoffee and vine are both perennial plants that are cultivated for their fruits on large areas in tropical and Mediterranean areas respectively. They are very similar in their structure with signicant areas of bare soil. Coffee is mostly grown in agroforestry systems, while vineyards are grown mostly as pure crops. Heavy pesticide use, soil degradation and loss of biodiversity are problems faced by both systems. Therefore, the use of trees in both systems may target some common problems, such as water contamination or pest control. In this paper we address two questions: 1) What lessons could be learned from coffee systems regarding the use of trees?; and 2) What are the differences in light competition with trees at different latitudes (Mediterranean versus tropical)? Shade is sought for coffee production in the tropics, but light competition by trees is considered detrimental for vine growing. However, vine was originally grown as an agroforestry system. The dynamic prediction of radiation patterns below the canopy of wide-spaced trees is essential to predict the outcome of agroforestry systems. A light competition model was used to calculate the impact of various tree canopy sizes and tree-row orientations on the distribution of the light at the coffee or vine level. For a given tree density and tree leaf area, the in!uence of the shape of the tree crown on the light availability for the crop is discussed. Surprisingly, erected and !at canopies were equivalent in the Mediterranean zone, but induced very different light patterns for the crop in the tropics. Tree-row direction was essential in Mediterranean latitudes and important in tropical latitudes to obtain a homogeneous radiation on the crop, which is counter-intuitive. Practical consequences for the choice and the management of shade trees with perennial crops are discusse

Vineyard agroforestry: a new concept for a sustainable vineyard production

National audienceGrape vines are one of the few crops in the world that is cropped only as a pure crop system. Vineyards face severe environmental concerns such as soil degradation, heavy loads of pesticides and pests attacks. In Roman times, vineyard cultivation was performed as an agroforestry system called Arbustra, with vines growing on living trees used as trellises. Scattered trees such as peach, almond or olive trees were also grown in vineyards in Europe until recently. These trees have been destroyed to allow easy mechanisation of the vineyard management, including mechanical harvesting of grapes. New vineyard agroforestry plots were set up in 1996 in the south of France, and have been monitored since then for grape production and tree growth. Various tree species were introduced into vineyards, at a density of 222 trees/ha, on shallow rocky soils prone to drought. Both evergreen resinous and broadleaved deciduous tree species were introduced, with Sorbus domestica (Service tree) and Pinus pinea (Stone pine) as the key species. Control plots with pure tree and pure vine plantation were available. After 12 years of cultivation, grape production and tree growth data showed that vineyard agroforestry is possible. Tree growth is enhanced in the agroforestry system, and grape production is not yet reduced by tree competition, except on extremely shallow soils. Competition for water and/or nutrients appears to be the main limiting factor, while light competition seems not to be a problem so far. Root pruning with a sub-soiler was used to limit water competition by the trees on the vines and proved useful. Some preliminary assessments of pest predators in the vineyard system show that mite control may be enhanced by the presence of trees in vineyards. This could allow a reduction in the use of pesticides in vineyards, but more detailed studies are needed to con!rm this hypothesi