STUDIES ON CARBON DIOXIDE PRODUCTION IN SOIL AND SOLUTION1

Abstract

SUMMARY The rate of carbon dioxide production by B. prodigiosus from various sugars has been studied and an account of experiments conducted with a view to finding out the factor or factors responsible in lowering the carbon dioxide production in soil and solution is given. It is found that B. prodigiosus can decompose glucose and laevulose most readily while sucrose comes next in order. Lactose and maltose are very slightly decomposed. The amount of carbon dioxide produced is not equivalent to the amount of sugar used up. Other organic products like alcohol, acetone and organic acids are produced. Carbon dioxide production always attains its highest limit within the first three or four days and then declines rapidly in spite of the presence of sugar and active organisms. Successive additions of fresh quantities of sugar to solution cultures when the carbon dioxide production has reached its minimum rapidly increase the carbon dioxide formation to a value practically identical with that previously attained. It appears that exhaustion of total or readily available carbon, formation of an unattackable film on the surface of particles of organic matter, or exhaustion of available mineral constituents is not responsible for lowering the carbon dioxide production in soil. Additions of organic matter such as glucose' or oil cake to soil after the carbon dioxide production has declined, restores the process practically to the same level as at the start.