Chapitre 4 - Innover dans les systèmes de culture et de production

Les systèmes agricoles intensifs, fortement utilisateurs d’intrants chimiques (engrais, pesticides, produits vétérinaires), et largement mécanisés, dominent aujourd’hui l’agriculture des pays développés et s’affirment aussi dans de nombreux pays du Sud. Ils sont généralement plus productifs à l’hectare que les systèmes traditionnels ; ils sont également le plus souvent économes en main d’œuvre, et ont permis un accroissemen..

Effects of crop management and surrounding field environment on insect incidence in organic winter oilseed rape (Brassica napus L.)

Many organic farmers hesitate to grow winter oilseed rape (WOSR), despite its usefulness for crop rotations and animal fodder, because it is attacked by many insects, which are difficult to control without chemical treatments. In a geographically broad network of farmer’s fields, we analysed the effect of various crop management factors and of the surrounding field environment on a large range of insects known to damage WOSR: root maggot (Delia radicum L.), cabbage stem flea beetle (Psylliodes chrysocephala L.), rape stem weevil (Ceuthorhynchus napi Gyl) and pollen beetle (Meligethes aeneus F.). Our results confirm the effect of sowing date, plant density and soil tillage regime on root maggot attacks and cabbage stem flea beetle larva infestation. Early sowing tended to increase root maggot damage whereas it was associated with a lower level of attack of cabbage stem flea beetle. High plant density tended to decrease the damage or the attack of all insects. We show that nitrogen availability in the soil affect cabbage stem flea beetle, stem weevil levels and pollen beetle damage: the negative effect of soil nitrogen content on pollen beetle damage may be related to the significant effect of nitrogen on plant vigour and, therefore, to the compensation of pollen beetle damage on new racemes. If all insects were considered together, the proportion of land under WOSR in the region and the surrounding environment had a significant effect on pest occurrence. In regions with a high proportion of land under WOSR, the proportion of plants attacked by root maggot and pollen beetle tended to increase. Conversely, regions with high proportions of land under WOSR tended to have a smaller proportion of plants with cabbage stem flea beetle larvae or damage, whatever the environment surrounding the field. For almost all the pests considered, the fields displaying the most severe pest attacks in regions with more than 1.2% WOSR were bounded by trees, hedges and bushes. Conversely, in regions with a lower percentage of land under WOSR, woodland around the field reduced the occurrence of pest attack

Tracking on-farm innovations to unearth alternatives to the dominant soybean-based system in the Argentinean Pampa

International audienceAbstractFarming activities in the Argentinean Pampa have focused on soybean production since the 1990s. The resulting cropping systems may not be sustainable in the long run due to development of glyphosate-tolerant weeds, homogenization of landscape mosaics, and pollutions. Here, we used the tracking on-farm innovation method to produce resources for the design of alternatives. The five steps of tracking on-farm innovation were (1) characterization of the soybean-based dominant cropping system, (2) identification of producers developing alternative systems, (3) description of these cropping systems and their agronomic logic, which is the link between the producer practices and their motives when choosing these practices, (4) multicriteria assessment of the performances of the systems, and (5) analysis of the development conditions of the most efficient systems. We identified 22 alternative cropping systems developed by farmers. These systems all include original practices: diversification of crop rotations (22 cases), occasional return to tillage (15 cases), and low pesticide use (16 cases). Some alternative systems were more sustainable than the soybean-based system, as shown by lower economic risk level, better ability to maintain soil organic carbon content, and less glyphosate-tolerant weeds. Our results show overall that tracking on-farm innovations is an efficient method to get references on alternative cropping systems developed by farmers

Chapitre 5 - L’innovation au cœur de l’histoire de l’agronomie

« L’agronomie est la science qui enseigne les moyens d’obtenir les produits des végétaux de la manière la plus parfaite et la plus économique » (de Gasparin, 1854, cité par Morlon, 2019). “Agronomy is focused on new and improved ways of agriculture”, ajoute le site de la Iowa State University. Contribuer au processus d’innovation, pour aider les agriculteurs à cultiver « de la manière la plus parfaite », est donc bien un enjeu majeur pour l’agronomie (Papy, 2006). Que ce soit dans la product..

Le Grenelle de l’environnement : implications pour l’agronomie et les métiers d’agronomes

National audienceLe Grenelle de l’Environnement impose des approches multicritères, suggère une diversification des échelles d’appréhension des questions etd’action, et accroît les obligations de résultat. Ce faisant, il renouvelle les questions posées aux agronomes, et contribuera à faire évoluerl’agronomie ainsi que les métiers qui la mobilisent. Les objets d’étude de la discipline devront ainsi être enrichis (meilleure prise en compte de la composante biologique, intégration d’éléments territoriaux non cultivés…), et les méthodes d’investigation (développement de méthodesmulti-échelles et comparatives, travail sur des systèmes en rupture fort…), et les modes de valorisation des connaissances agronomiques(valorisation des savoirs locaux, investissement dans l’appui à l’action publique…) diversifiés