AGGREGATION OF SOIL PARTICLES BY NOSTOC-MUSCORUM AG (CYANOBACTERIA)

The effect produced by the addition to the soil of a continuously rene wable organic matter source (Nostoc muscorum Ag.) on the stability of soil aggregation and other physico-chemical and biological properties responsible for soil aggregation were determined. The inoculated soil shows an increase of 56% of aggregates bigger than 250 mu and a decrea se of 18.3% of aggregates smaller than 2 mu. This stability is a conse quence of the increase in the microbiological activity and also of the concentration of polysaccharides (mainly produced by the cyanobacteri a) in the soil.