Influence of soil-aggregating substances on the population of gum-producing bacteria in a loess soil

Summary

Three forms of a Belgian poly-electrolytic resin product manufactured for use as a soil aggregating substance were compared with the similar American product Krilium in respect to water-stable macro-aggregate formation in a loess soil and the associated population of gum-producing bacteria over a period of ten weeks.

The Belgian product gave appreciably better aggregation of this soil. All products stimulated an augmentation of gum-producing bacteria in the treated soil.

In general the Belgian product produced a rather greater augmentation in the number of such bacteria over the period of the investigation, there being apparently a positive relationship between increased aggregation up to moderate levels and increased bacterial numbers.

However, the augmentation of bacterial numbers in the surface soil was not generally very great in comparison with the untreated soil.

The production of various levels of soil aggregation introduces technical difficulties and makes very difficult the accurate interpretation of results obtained from the plating of soil samples of distinctly different aggregation status.

No evidence was found to prove the toxicity of these products to such bacteria when used up to the 0.1% level; nor was there any toxic effect of some decomposition product apprent during the course of these investigations.