The legume choice determines crop production, nitrogen dynamics, weed control and economic viability of relay intercropping in a Mediterranean cereal based low-input cropping system

The relay intercropping of subsidiary legumes with durum wheat (living mulch) can be a valuable agroecological practice to supports nutrient availability and non-chemical weed control at crop rotation level without negative impacts on crop productivity (Tosti et al., 2016; Hiltbrunner et al., 2007). This study aimed to investigate the long-term agronomical and economical sustainability of eight different legumes among perennial, annual and annual self-seeding species tested in relay intercropping with durum wheat in a Mediterranean low-input cereal-based cropping system. In particular we evaluated the impact of each legume on 1) intercropped wheat, through the evaluation of N uptake, grain yield and protein content, 2) the subsequent forage sorghum taking into account the residual effects of the legumes on the following summer crop through the evaluation of biomass production and N uptake, 3) the effects of legume on weeds community composition and biomass before and after wheat harvest and in the subsequent cash crop. Finally we performed an economic assessment to test if costs due to the relay intercropping are balanced by the ecosystem services it provides at crop rotation level taking into account the impact of the legumes on the co-cultivated wheat and on the following forage sorghum.