Many kinds of gases that are globally and regionally important are exchanged in terrestrial ecosystems. I present rough summary of exchanges of H2, CO, CH4, NO, and N2O of upland soils. H2, CO, and CH4 are absorbed (oxidized) by upland soil, whereas NO and N2O are emitted from upland soils.

It is natural that NO and N2O emissions are larger when nitrogen contents (or ammonium and nitrates) are higher. NO is emitted under relatively-dry conditions, whereas N2O is emitted under relatively-wet conditions. It should be noted that actual NO formation reaction during nitrification processes is not still unknown and under wet conditions which is optimal for N2O production, simultaneous nitrification and de-nitrification processes are in progress in soil. As far as I recognize, models are not successful to describe N2O emission from soil.

H2, CO, and CH4 are oxidized by soil bacteria. Uptake rates of these gases are linearly dependent on concentration of the gases under low concentrations as in the atmosphere. Surprisingly the temperature dependence of uptake of these gases are similar. Only a few bacteria is known to oxidize H2 and CO and a lot of mechanisms are unknown for H2 and CO uptake by soil.