Can intercropping stabilize yields in the face of climatic changes?

Intercropping has been proposed as a way to reduce some of the negative consequences of intensive agriculture while maintaining or enhancing crop yields. Not only yields can be increased in intercrops, but they can also be more stable in the face of variable climatic conditions, offering an avenue of climate change adaptation. Nevertheless, exploiting the benefits of intercropping requires determining what the most appropriate members of the plant team are, and matching plant team and management to the local pedoclimatic conditions. Process-based mathematical models can complement field experiments to quantify via numerical simulations the performance of a variety of combinations of plant teams, management, and pedoclimatic conditions. These models are particularly useful when exploring the potential advantages of intercropping under climate change. Here we use the newly developed model M3 (Minimalist Mixture Model; Berghuijs et al, Plant and Soil, 2020) to simulate the biomass and grain yields of pure culture or intercropping systems, as a function of plant traits, management and environmental conditions. Focusing on wheat and faba bean grown in pure culture and intercrop in the Netherlands and Central Sweden, we quantified crop yields and their stability over the period 1951-2100, exploiting modelled climatic data series. We found large interannual variability in yields both on a per unit area and per plant basis, mostly due to the interannual variability in weather conditions. On a per unit area basis, yield differences between crops and cropping systems are consistent under historical and future climatic conditions. However, under future climatic conditions, the yields per plant were lower in faba bean, but not in wheat. Overall, pure cultures benefitted from future climatic conditions, while intercrops appeared to be negatively affected. Moreover, climate change increased yield variability in both crops and cropping systems. Therefore, against expectations, intercropping does not necessarily reduce yield variability with respect to pure culture