Agronomy and Horticulture Department


Date of this Version



Published in Soil Science of America Proceedings (April 1955) v. 19, no. 2: 179-181.


Twelve cellulose-decomposing fungi were tested for aggregating ability with Peorian loess containing ground straw at a concentration of 1%. Of the 12 fungi, Stachybotrys atra was the most effective soil aggregator. Under laboratory conditions used, it produced from 2 to 30 times more aggregation than any of the other fungi tested. Studies were made of the influence of various environmental factors on the degree of aggregation effected by S. atra. An incubation time of 1 week was sufficient for a relatively high degree of aggregation. In comparison, longer periods resulted in only slightly improved aggregation. Varying the temperature between 20° and 28° C. had no appreciable effect on the aggregation by S. atra. Approximately equivalent aggregations were attained at the moisture levels of 20, 25, and 30%, which were definitely superior to the 10 and 15% levels. Alfalfa and straw, either separately or as a mixture, were satisfactory sources of energy material for S. atra. The aggregation obtained with alfalfa, however, was somewhat higher than that obtained with straw,