Title : Species proportion modulates biomass allocation, nitrogen dynamics and soil biogeochemistry in rye–vetch intercropping systems
Abstract:
Intercropping cereal–legume species is a well-established strategy to enhance agroecosystem sustainability, yet the influence of species proportion on plant performance and below-ground processes remains incompletely understood. In this study, we investigated how varying the relative abundance of rye (Secale cereale L.) and vetch (Vicia sativa L.) affects plant nitrogen (N) acquisition, biomass partitioning, and soil biochemical activity under controlled conditions. The experimental design included four treatments: monocropping (100% rye or 100% vetch) and intercropping with two contrasting species ratios (66:33 and 33:66 rye:vetch). Root and shoot dry biomass and total N content were quantified, alongside soil analyses encompassing nitrogen-related enzyme activities, untargeted metabolomic profiling, and ^15N stable isotope analysis. Preliminary findings indicate that species proportion strongly influenced both biomass allocation and N distribution within plant organs. Intercropping enhanced complementary interactions in N use and altered the balance between soil- and symbiotically-derived N sources. Soil enzymatic activities linked to the N cycle, as well as metabolomic fingerprints, varied across treatments, reflecting shifts in microbial function and plant–microbe interactions. Overall, our results highlight that species proportion is a key driver of both plant-level responses and rhizosphere biochemical processes in mixed cropping systems. Understanding these interactions is essential for designing functionally optimized intercropping strategies that support nutrient efficiency and soil health.
Key words: Intercropping, Legume–Cereal Mixtures, Nitrogen Use, Root–Shoot Allocation, Soil Biogeochemistry, Plant–Microbe Interactions
