Enhanced Yields in Organic Arable Crop Production by Eco-Functional Intensification using Intercropping

Organic agriculture (OA) faces challenges to enhance food production per unit area and simultaneously reduce the environmental and climate impacts, e.g. nitrate leaching per unit land and green-houses gases (GHG) emissions per kg product. Eco-functional intensification (EFI) is suggested as a means for enhancing yields in OA. EFI involves activating more knowledge and intensifying the beneficial effects of ecosystem functions, including agrobiodiversity (planned and associated) and soil fertility, and refocusing the importance of ecosystems services in agriculture. Organic farmers manage agrobiodiversity by planned crop diversification in time (crop rotation). However, cultivating genetically identical plants in OA sole crops (SC), limits resource use efficiency and yield per unit area. Intercropping (IC) of annual species or cultivars, perennial polycultures of forage or grain crops and agroforestry are examples of spatial crop diversification, which based on eco-functional intensification may enhance yield by the interspecies competitive production principle, only partly niche overlap and complementarity in resource use in time and space. Intercropping of species is based on the ecological principles of competition, facilitation and complementarity. We show that intercropping of cereals and grain legumes in European arable OA systems is an efficient tool for enhancing grain yields compared to the growing of sole crops. Simultaneously, we display how eco-functional intensification by intercropping can be used as an efficient tool for weed management, enhanced product quality (i.e. grain protein concentration of the intercropped cereal). We discuss how ICs contribute to efficient use of soil N sources and minimized losses of N by leaching via “ecological precision farming”. It is concluded, that crop diversification in space by intercropping, fitted into the organic crop rotation, has a strong potential to increase yield and hereby reduce the global environmental effects performance such as GHG per kg organic grain. Finally, we discuss likely barriers for increased use of intercropping in organic farming and suggest a roadmap for innovation and implementation of crop diversification by IC in organic agriculture