Associated crops are defined as the simultaneous cultivation of two or more species on the same area during a significant period of their growth cycle. These multi-species assemblages, and in particular the mixture of cereals and legumes, are common in their natural state in pasture systems. But associations have virtually disappeared from European cultivated agrosystems as a result of the intensification of agriculture over the last 50 years. The principle of cereal-legume associations is based on the complementarity between the species cultivated for the use of the available resources (water, light, nutrients) and first of all nitrogen, since legumes are capable of fixing atmospheric nitrogen. Thus, species mixtures appear as an interesting agronomic solution and in particular for organic farming, where the availability of nitrogen can sometimes be limiting, and biotic factors (diseases, pests and adventitious), often important. Both can jointly cause yield losses and affect the technological qualities of the products.
Several studies show the agronomic advantage of the associated crops for the yield. In fact, two herbaceous association crops produce, on average, 30% more grain than the separate crop in organic farming. On the other hand, associations are particularly advantageous in situations where the yield of at least one of the main crops is low, which confirms the interest of these systems in unfavorable agronomic conditions or with low potential.
Source: Research Gate and Fundación Global Nature