Steering microbiomes by organic amendments towards climate-smart agricultural soils

We steered the soil microbiome via applications of organic residues (mix
of cover crop residues, sewage sludge + compost, and digestate + compost)
to enhance multiple ecosystem services in line with climate-smart
agriculture. Our result highlights the potential to reduce greenhouse
gases (GHG) emissions from agricultural soils by the application of
specific organic amendments (especially digestate + compost).
Unexpectedly, also the addition of mineral fertilizer in our mesocosms led
to similar combined GHG emissions than one of the specific organic
amendments. However, the application of organic amendments has the
potential to increase soil C, which is not the case when using mineral
fertilizer. While GHG emissions from cover crop residues were
significantly higher compared to mineral fertilizer and the other organic
amendments, crop growth was promoted. Furthermore, all organic amendments
induced a shift in the diversity and abundances of key microbial groups.
We show that organic amendments have the potential to not only lower GHG
emissions by modifying the microbial community abundance and composition,
but also favour crop growth-promoting microorganisms. This modulation of
the microbial community by organic amendments bears the potential to turn
soils into more climate-smart soils in comparison to the more conventional
use of mineral fertilizers.