Resource acquisition and interactions in spring wheat/faba bean intercropping under diverse environments

Context: Cereal/legume intercropping offers numerous advantages over monocultures, often attributed to complementary resource use of soil water, soil nitrogen (N), and radiation. Objective: This study explores how the dynamics of crop resource (radiation, water, soil N) demand and use drive productivity in intercropping systems under different environmental conditions. Methods: We used a process-based intercrop simulation model and field experimental data obtained from three contrasting environments with differing soil N and precipitation levels. Spring wheat and faba bean were sown as monocultures and intercropped in a 1:1 replacement design. Results: The simulations and field experiments revealed no considerable differences in total water uptake and light interception between intercrops and the average of monocultures across environments. Intercrops acquired more soil N than the average of monocultures in all environments. Spring wheat in intercrop systems consistently acquired more soil water and N compared to spring wheat in monocultures. Faba bean resource acquisition and use efficiency depended on the environmental conditions. Resource use efficiency of intercropping was comparable to that of the monocultures, except for N use efficiency, which was 22 % higher, and water use efficiency which was 12 % higher under low N and the low precipitation environment. There was a slightly enhanced water use efficiency in the intercropping system compared to monoculture under high N and high precipitation environment. In environments with limited water, intercropped faba bean suffered considerably from drought stress, particularly during flowering compared to the monoculture of faba bean. Conclusions: Soil water availability is a key determinant for faba bean productivity in intercropping, while mainly soil N availability influenced spring wheat productivity compared to its corresponding monocultures. Overall, there was small (high precipitation) or no (low precipitation) increase in radiation and water acquisition in the intercrops but there was a large increase in N uptake in all cases. Significance: Designing site specific spring wheat/faba bean intercropping systems enhances the availability of N and use efficiency, which helps to minimize N input.