Wheat-faba bean intercropping can sustain soil nutrients and C cycles under different N fertilization levels

Legume-cereal intercropping systems are expected to play a significant role in promoting the sustainable enhancement of crop yield per hectare with reduced synthetic inputs. However, the effects on soil nutrients and C biogeochemical cycles in this multi-cropping system are not fully elucidated. In this study, wheat-faba bean intercropping effects on soil nutrients and C cycles were investigated under field conditions. The underlying hypothesis is that the more diversified rhizodeposition in intercropping may sustain nutrient and C cycling in soil more effectively than the respective sole crops. To test this hypothesis, soil and plant Total N and C (TN and TC) and their stable isotopic compositions (δ15N and δ13C) were quantified, along with plant-available N forms in soil (ammonium and nitrate). Furthermore, the variations in soil Microbial Biomass N and C (MBN and MBC) and nutrients (P, K and micronutrients) were measured. Net Ecosystem Production (NEP) was also determined at crops flowering stage. Results are currently under statistical analysis. It is anticipated that intercropping may have led to a higher NEP, resulting in increased soil TC stocks. Moreover, N retention and availability for plants are expected to be higher in intercropping. It is also hypothesized that intercropping may have mediated a higher mobilization of P, K and micronutrients. The lower C:N ratio of rhizodeposits compared to sole wheat is predicted to facilitate microbial growth, ultimately sustaining MBN and MBC accumulation. Overall, it is expected that co-cultivating wheat and faba bean could lead to an improved Plant-Soil Feedback.