|The combined effects of faba bean and endogeic earthworms on soil microbial activity in intercrops
|Year of Publication
|Drut B., Fustec J., Oddos L., Cannavacciuolo M., Brauman A., Cassagne N.
|European Journal of Soil Biology
|Type of Article
|Agriculture, aporrectodea-caliginosa, carbon, community composition, diversity, dynamics, Endogeic earthworms, Environmental Sciences & Ecology, functional diversity, Legume, Microrespiration, plant, Plant species, rhizosphere, root traits, triticum-aestivum l., zea-mays l.
The rhizosphere is a hotspot of interactions between plants and soil organisms that affect the soil functioning and nutrient cycling. The drilosphere is a hotspot of interactions between earthworms and soil microbial communities affecting plant growth, soil aggregation, and porosity. Central to these interactions are microorganisms, which are affected by both plant species diversity and earthworm activity. Little is known about the effects of earthworms on the microbial community activity under the influence of root-trait diversity in cases of multispecies plant covers. We investigated the impact of plant composition and the presence of endogeic earthworms on the metabolic response of microorganisms to the addition of 10 carbon substrates relevant as rhizodeposition components. A greenhouse experiment was conducted with mesocosms filled with 10 kg of soil, sown with two plants of either the same or different species, chosen based on their contrasting root traits. Five modalities were investigated: 1 faba bean (Vicia faba L. ssp. Minor) intercropped with either 1 rapeseed (Brassica napus L.) or 1 wheat (Triticum aestivum L.) plant, as well as crops of the same species: either 2 rapeseeds, 2 wheats, or 2 faba beans. For each modality, 10 mesocosms were set up, and half of them were inoculated with 5 endogeic earthworms (Aporrectodea caliginosa Savigny). After 91 days, the plants' dry weight, N content, and 15N:14N ratio were measured. The rhizosphere microbial respiration was assessed using the MicroRespTM method. The results showed that the level of metabolic activity depends on the plant species composition. Faba bean had the highest positive effect on microbial growth and metabolic activity. Microbial activity was also significantly increased by earthworms, but with no specific effect between plant treatments. Our findings suggest that plant traits are the main driver of the metabolic activity of soil microorganisms that is stimulated by earthworms.
|Eur. J. Soil Biol.