The Effect of Partial Sterilisation of Soil on the Production of Plant Food: Part II. The Limitation of Bacterial Numbers in Normal Soils and its Consequences

Abstract

The conclusions reached in our previous paper have been confirmed and extended. Fresh evidence is adduced that bacteria are not the only inhabitants of the soil, but that another group of organisms occurs, detrimental to bacteria, multiplying more slowly under soil couditions and possessing lower power of resistance to heat and to antiseptics. In consequence of the presence of these detrimental organisms the number of bacteria present in the soil at any time is not a simple function of the temperature, moisture content and other conditions of the soil. It may, indeed, show no sort of connection with them; thus rise of temperature is found to be ineffective in increasing the bacteria in the soil; increase in moisture content has also proved without action. The number of bacteria depends on the difference in activity of the bacteria and the detrimental organisms.