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

Abstract

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 (eCO2) and temperature (eT), and a multicomponent (eCO2eT) 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 eCO2eT 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 eCO2 and eCO2eT compared to ambient conditions. The microbial community had a preferential (p =.024) consumption of C3 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 eCO2, whereas N2O fluxes were greater (p =.005) with eCO2 and eCO2eT. However, greenhouse gas fluxes from the intercrop were similar between eT or eCO2eT 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 eCO2eT.