Functional approach to associated crop species choice in soybean-based intercrops and spatial arrangement : impact on services obtained during and after intercropping. ; Approche fonctionnelle du choix de l’espèce associée au soja et arrangement spatial dans les associations de cultures : impact sur les services obtenus pendant et après la culture.

Diversification is necessary to improve cropping systems sustainability. However, diversification crop introduction into cropping systems is confronted to many barriers. Soybean, a leguminous crop producing protein rich grain, is a potential diversification crop which beneficiate from a favourable context for its development in France. Weed growth reduction et yield stabilisation are important issues for producers. In order to facilitate cropping system diversification, we suggest the use of intercropping to solve these problems. To test this strategy, four services: soybean grain production, associated crop grain production, weed control and nitrogen pre-crop effect are assessed under the influence of two management levers: associated crop species choice and spatial arrangement of crops. Functional approach was used to identify traits associated to crop growth and functions. Associated crop had an impact on all services considered in this work. A trade-off was identified between soybean production service and weed control service. Nonetheless this trade-off could be modulated in some intercrops through spatial arrangement. Functional approach helped identify effect traits related to the growth dynamics of the crops and to the persistence of crop residues. In addition we show that crop traits response to management was low. Finally, intercropping soybean mofifies some parts of nitrogen balance as well as the quantity and quality of crop residues. Nonetheless, no differences were measured on the following wheat between intercrops and sole cropped soybean ; La diversification des systèmes de culture est un enjeu important pour améliorer leur durabilité. Cependant, l’introduction de cultures de diversification est confrontée à de nombreux freins. Le soja, une légumineuse produisant des graines riches en protéines, est une culture de diversification potentielle qui bénéficie d’un contexte favorable à son développement en France. Mais la maitrise de la croissance des adventices et la stabilisation des rendements sont ...