Lucerne (Medicago sativa) alters N2O-reducing communities associated with cocksfoot (Dactylis glomerata) roots and promotes N2O production in intercropping in a greenhouse experiment

Publication date: Available online 30 July 2019Source: Soil Biology and BiochemistryAuthor(s): Daniel R.H. Graf, Aurélien Saghaï, Ming Zhao, Georg Carlsson, Christopher M. Jones, Sara HallinAbstractLower emissions of the greenhouse gas nitrous oxide (N2O) are generally observed from intercropped compared to sole cropped systems. This could be due to better N-use efficiency, but differences in microbial communities establishing in the rhizosphere may also play a role as the only known biological sink for N2O is its reduction to nitrogen gas (N2) by bacteria and archaea that possess the nosZ gene encoding the N2O reductase. Nitrous oxide reducing communities can be divided into two clades, I and II, and their relative abundance and diversity may have important consequences for N2O emissions. Here, we examine how intercropping with a legume (Medicago sativa, “lucerne”) and a grass (Dactylis glomerata, “cocksfoot”) species, compared to sole cropping of each species, affects the N2O emission potential, and the structure and abundance of root-associated N2O-reducing microbial communities. In a rhizobox experiment, we show that intercropping resulted in higher total shoot biomass compared to sole cropping. Further, N2O production rates were significantly higher in intercropped cocksfoot roots compared to sole cropping of either species. This coincided with lower abundances of nosZ clade II communities in intercropped compared to sole cropped cocksfoot roots, suggesting tha...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research