Elevated carbon dioxide and temperature effects on soil properties from sole crops and intercrops

Climate change is associated with more intense phases of heat, drought or precipitation that can have a negative impact on soil properties. Our goal was to understand if elevated CO2 (eCO(2)) and temperature (eT), and a multicomponent (eCO(2)eT) climate effect will influence soil properties from cereal-legume intercrops differently compared to sole crops. We hypothesized that cereal-legume intercrops can regulate climate effects, causing soil properties and greenhouse gas fluxes to be similar to ambient climate conditions. eT and eCO(2)eT decreased soil organic carbon (C) (p = .001) and nitrogen (N) (p = .003) but increased (p = .011) soil nitrate in all crop systems, compared to ambient conditions. For crop systems, soil ammonium was lower (p = .001) with all climate effects, but nitrate was greater (p = .011) with eCO(2) and eCO(2)eT compared to ambient conditions. The microbial community had a preferential (p = .024) consumption of C-3 sources in the sole crops. Climate effects also influenced how C and N were accessed by microbes in all crop systems, shifting (p = .001) species richness and microbial community structure. CO2 fluxes were greater (p = .001) with eT and eCO(2), whereas N2O fluxes were greater (p = .005) with eCO(2) and eCO(2)eT. However, greenhouse gas fluxes from the intercrop were similar between eT or eCO(2)eT and ambient conditions. For soil properties, we rejected our hypothesis since cereal-legume intercrops did not have an advantage over sole crops to cope with single- and multicomponent climate effects, but we partially accepted our hypothesis since greenhouse gas fluxes were similar between AMB and eT or eCO(2)eT.