Rothamsted Research: Crop species, not soil type, drive beneficial root microbiome functions

The crop type in a field plays a greater role than soil type in determining which beneficial microbial functions develop around plant roots, according to new research from Rothamsted Research that could influence the next generation of biofertilizers and microbial inoculants.

Published in the journal ISME Communications, the study examined six major arable crops — wheat, barley, oats, fava beans, oilseed rape, and sugar beet — grown in soils from nine locations across the United Kingdom. While the composition of bacterial communities in the rhizosphere, the soil zone immediately surrounding roots, varied by soil origin, researchers found that the functional traits of those microbial communities were consistently shaped by the host crop rather than local soil conditions.

The researchers identified distinct crop-specific microbial functions. Sugar beet and oilseed rape recruited bacteria linked to drought tolerance, likely reflecting drier conditions created by their deep taproot systems. Barley favored microbes that mobilize zinc from soil minerals, an important nutrient for grain development. Fava beans, which obtain nitrogen through symbiotic fixation, attracted fewer bacteria involved in organic nitrogen breakdown, suggesting complementary rather than overlapping nutrient acquisition strategies.

The findings could have significant implications for the development of biological fertilizers. If crops consistently select for specific microbial functions regardless of soil type, manufacturers may design microbial inoculants tailored to individual crops rather than products tailored to specific soil conditions. This approach could broaden product applicability, improve field performance consistency, and reduce development costs.

The study adds to growing evidence that plants actively shape the microbial communities around their roots. Researchers said the results suggest crop rotations influence not only nutrient cycling but also the range of microbial services available in agricultural soils over time. For companies developing biological nitrogen fixation technologies and nutrient-mobilizing products, the findings support crop-focused formulation strategies as a more effective path to commercialization.

Source: Phys.org