Carbon Dioxide from the Soil and Plant Assimilation

Abstract

THE rôle of carbon dioxide formed as the result of biological decomposition of organic matter in the soil has long been a subject of controversy among scientific workers, one school of thought holding the view that it facilitates increased assimilation, and the other that it has no beneficial effect on plant life¹. There is also difference of opinion as to whether the increased concentration of carbon dioxide observed around the growing plant is the result of oxidation changes in the soil or merely plant respiration. The position is still obscure because (a) no systematic experiments would, so far, appear to have been carried out, growing plants in the absence of atmospheric carbon dioxide, and (b) the carbon and oxygen relations between the soil, the plant and the atmosphere have not yet been studied collectively, so that it is not possible to define, at any particular stage, the extent to which the plant is indebted to the atmosphere or the soil for the carbon dioxide assimilated by it.