text: In concluding, the five researchers say "it is possible, therefore, to enhance the biomass yield of this green manuring crop by elevating the level of CO 2 in the plant canopy." One low-tech way of doing so is suggested by their statement that "plant residues decomposing on the soil surface following mulching may help elevate the level of CO 2 and thus the plant growth," while we suggest that a longer-term strategy would be for the nations of the earth to not overtly strive to reduce anthropogenic CO 2 emissions associated with the burning of fossil fuels; for CO 2 is "the elixir of life."