Microbiological analysis of soil as an index of soil fertility. VII. Carbon dioxide evolution

Microbiological analysis of soil as an index of soil fertility. VII. Carbon dioxide evolution

Author: Jean-François Ponge

Year: 1924

Determination of the amounts of carbon dioxide evolved from the soils, both without and with the addition of small amounts of organic matter, can be used in grading these soils on the basis of their fertility as well as can determinations of the numbers of microorganistns and nitrification in the soil. The data presented in this paper together with those published previously on the microbiological analysis of soils allow us to look forward to the development of a group of quantitative methods for determining the proquctive capacity of the soil. To measure the capacity of the soil to produce carbon dioxide, two methods are suggested: one, determining the amount of carbon dioxide formed from one kilogram of fresh soil, for fourteen days under optimum conditions of temperature and moisture; two, determining the amount of carbon dioxide produced from 500 mgm. of dextrose added to 100 gm. of fresh soil, in forty-eight hours. Soils rich in organic matter produce by far the greatest amount of carbon dioxide (this does not apply to peats, mucks or such abnormal soils). The amount of carbon dioxide produced is not, however, proportional to the carbon content of the soils. The addition of li