Exploring the relationship between soil mesofauna, soil structure and N2O emissions.

We analysed soil structural parameters using X-ray tomography to explain the role of soil mesofauna in nitrous oxide emissions (N2O) from agricultural soil. The experiment was set up in the Soil Physics Laboratory:

Potworms, fungivorous mites and predatory mites were introduced into the microcosms (and all of their combinations):

N2O and also CO2 fluxes were measured with a static closed chamber
technique, type 1302 multi gas monitor (Brüel & Kjaer, Naerum, Denmark).

Potworms accelerated peak N2O emissions, but neither fungivorous mites nor predatory mites nor their interactions had a significant effect on N2O
emissions.

Soil scanning (X-ray tomography) was performed using the v[tome]x m (Phoenix X-ray/General Electric). Potworms clearly affected the soil structure by increasing the volumetric air content and altering the pore size distribution. In addition, visual observations indicate a more continuous pore network in the soil microcosms when potworms are present:

Control.............................................................With potworms

In conclusion: soil structure is an important pathway driving faunal-induced N2O emissions, and soil ecosystem engineers such as potworms disproportionally affect N2O emissions as compared to other soil fauna.

Reference:

Porre RJ, Van Groenigen JW, De Deyn GB, De Goede RGM, Lubbers IM (2016) Exploring the relationship between soil mesofauna, soil structure and N2O emissions. Soil Biology & Biochemistry 96:55-64.