Faba bean-wheat intercropping sustains soil nutrient, but not carbon cycling in the short term

Legume-cereal intercropping systems are anticipated to play a significant role in the sustainable intensification of crop production, due to the increased yield per area. However, it has not been fully elucidated how nutrient and carbon (C) cycling are affected by this cropping system under field conditions at different phenological stages. To address this knowledge gap, an experiment was conducted in which winter wheat and faba bean were cultivated in field under varying nitrogen (N) fertilizer doses. The central hypothesis posited that co-cultivation could enhance C sequestration in soil and promote nutrient cycling closure. Various soil N and C pools were quantified, alongside the availability of the other macro- and micro-nutrients. The microbial functional potential was evaluated through the analysis of the enzyme activities and C Use Efficiency. The findings revealed that the intercropping with faba bean sustained the N cycling comparably to the normal N dose applied for wheat. Intercropping enhanced nutrient availability for plants at some phenological stages, especially close to the grain-filling phase. The soil phosphorous mineralization potential was also stimulated. Nevertheless, the short-term changes in C cycling were inconsistent. Overall, wheat-faba bean intercropping demonstrated a considerable potential for reducing the reliance on N fertilizers.