Microbial nature of the hydrogen-oxidizing agent in hydrogen-treated soil

Abstract.

Experiments have shown that legume soil can promote non-legume plant growth. Although generally attributed to N fertilization of the soil, there are other factors that are additionally responsible. Work has been done in an attempt to characterize this response; fungal agents have been implicated. Other studies have shown H₂ to be responsible for plant growth promotion. This work attempts to understand the nature of the H₂ uptake agent in soil. The H₂ uptake ability of H₂-treated soil disappeared when the soil was autoclaved or when glucose was added, suggesting the biotic nature of the H₂ uptake agent. Physical disturbance reduced the H₂ uptake ability of the soil, indicating the special colonial or long filamentous structure of the H₂ uptake agent in soil. The fact that the addition of fungicides did not, in most cases, significantly affect the H₂ uptake ability of the soil excluded the fungi as the H₂ uptake microorganisms in soil. Addition of antibiotics significantly affected the H₂ uptake ability of the soil suggesting the H₂ uptake agent in soil is bacterial. The H₂ uptake ability of soil was greatly reduced by extremely high concentrations of benomyl and a low concentration of penicillin, indicating that actinomycetes might be the active H₂ uptake bacteria in H₂-treated soils.