13C labeling experiment catch crops

We investigate the impacts of increasing plant diversity in catch crop rotations on rhizosphere C input and microbial utilization. Mustard (Sinapis alba L.) planted as a single cultivar was compared to diversified catch crop mixtures of four (Mix4) or 12 species (Mix12). We traced the C transfer from shoots to roots towards the soil microbial community and the soil respiration in a 13C pulse labelling field experiment. The data set included measurements of organic carbon, total nitrogen as well as their stable isotopes in plant and soil material. The growth and activity of the soil microbiome was investigated by phospholipid fatty acid (PLFA) analyses. The transferred of C from plants towards the microbiome was measured by 13C label concentration in specific PLFA markers.

More information is available: Gentsch, N., Boy, J., Batalla, J.D.K. et al. Catch crop diversity increases rhizosphere carbon input and soil microbial biomass. Biol Fertil Soils 56, 943–957 (2020). https://doi.org/10.1007/s00374-020-01475-8

Research domain: Soil Sciences

Research question: The aim of the study was to test how catch crop diversity affects C cycling from the atmosphere through the plant-soil-microbiome system. More specifically, the efficiency for C uptake and the belowground input of recently photosynthesized C products and their partitioning in the rhizosphere was investigated. We hypothesized that diversified catch cropping systems would (I) increase photosynthetic C fixation with higher transport rates of newly assimilated C to the roots, (II) stimulate microbial growth through higher C utilization when C reaches the rhizosphere and (III) prolongate the C cycling throughout the plant-soil-microbiome system.