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Agroforestry was first considered as a farming method restricted to the South only, but it has recently experienced new challenges in Europe. Agroforestry is defined as any combination of trees and crops or animals on the same plot. Once traditional and massively present, it has gradually disappeared from our landscape after the Second World War, when more space for larger plots was required to increase yields of monocultures. But this has led to many long-standing problems, changing biodiversity, ecosystems and even the vision of agriculture. To meet the new challenges of modern agriculture, many researches have been conducted to try to combine high yields with biodiversity and environmental protection, and it seems that agroforestry is in itself a promising response.
Indeed, this technique displays several advantages. First, from the social point of view, the establishment of trees around or inside cultivated fields provides more beautiful and diverse landscapes than monocultures. They can restore a more harmonious and peaceful agricultural land appearance, being more attractive for tourism. Silvopastoralism practices of cattle grazing under trees also help to cultivate fields which are difficult to work in and sometimes abandoned, such as some fields in the mountains. It is important to note that agroforestry can be coupled or not to organic or conventional agriculture, as it only defines a plot layout, and generally plays no role in the treatment applied to the fields.
In economic terms, it allows a significant diversification of activity for farmers; trees allow an entry of money over the long term while crops provide steady incomes. The tree seedling does not represent a big investment for farmers (from 400 to 1000 € / ha depending on the species) and requires almost no treatment until harvest. To ensure a constant tree cover and limit outbreaks between trees, planting different species is commonly used, which increases biodiversity even within rows of trees. In addition, trees may take advantages from the neighbour crops (fertilizer, irrigation …), and may grow faster than in conventional forestry. And if we can lose some cultivated area because of the trees, some clever associations on a plot can increase its returns up to 50% over two plots side by side; this is the case of the association between walnut tree and wheat. Throughout the year, the solar energy will be maximized by the two species: wheat will grow faster when the walnut trees have no leaves, and then the walnut trees will grow later and better, taking advantages of the agriculture inputs.
Agroforestry also displays many environmental benefits. It encourages cohabitation of several species, thus playing an important role in maintaining biodiversity – with trees being habitats of natural predators (bats, birds…) for certain pests (insects, rodents…). These cropping systems also reduce their consumption of inputs (fertilizer and water): leaves and tree roots can create a pool of organic matter for crops, while the thick foliage may limit evaporation and provides a more stable microclimate. A recent study reports the analysis of methods in agriculture for the U.S.A. during the last century, from data collected from 1900 to 2000; it shows that nitrate concentration measured in rivers (in relation with nitrogen fertilizer) increased significantly in monoculture systems, while the opposite trend was observed with agroforestry. It can be noticed that erosion is also reduced by agroforestry, with trees representing natural wind screens, favoring water infiltration and slowing runoff. Agroforestry could therefore be an important bulwark against pollution and soil depletion due to modern agriculture.
Thus, even if the annual increase of agroforestry surfaces in France is only about 6%, it can be expected agroforestry to emerge as a sustainable agriculture system in our landscapes. Providing a long-term investment (40 to about 60 years) for any farmer wanting to start with agroforestry, the European Commission should continue until 2020 to support agroforestry (with first actions being started in 2007 with the CAP6). And in order to get the opinion of an expert in the domain, we hope that we will be able to post soon on the AoB Blog the summary of an interview with one of the first researchers to have imported this concept in France: Christian Dupraz, researcher at INRA Montpellier.
2 : Balandier et al, “Agroforesterie en Europe de l’Ouest : pratiques et expérimentations sylvopastorales des montagnes de la zone tempérée“, Cahiers Agricultures, Volume 11, Numéro 2, Mars-Avril 2002, pages 13-103.
3 : Dupraz et al, “Incorporating agroforestry practices in the management of walnut plantations in Dauphiné, France: an analysis of farmers’ motivations”, Agroforestry Systems, Volume 43, Numéro 1-3, Mai 1999, pages 243-256.
4 : Sciences & Vie, “L’agro-diversité, recette contre les nitrates“,
http://www.science-et-vie.com/2009/02/11/lagro-diversite-recette-contre-les-nitrates, publié le 11/02/2009.
5 : Kaeser et al, “Agroforesterie moderne en Suisse, Vergers novateurs : productivité et rentabilité“, Station de Recherche Agroscope, Rapport ART 725, Juillet 2010, 12 pages.