The Microbiology of Farmyard Manure Decomposition in Soil II. Decomposition of Cellulose

Abstract

1. Addition of farmyard manure to soil gives rise, in laboratory experiments, to an abundant development of cellulose-decomposing bacteria of the genusVibrioin approximately neutral soils (^pH 6.5–7.0). In faintly acid soils (pH 5.7–6.2) these organisms develop less abundantly, and are partly replaced bySpirochaeta cytophaga. At lowerpH values only the fungi are active in the decomposition of cellulose. Similar results were obtained by adding filter-paper or straw to soils of different reactions. Of the fungi, Trichoderma and Penicillium appear more active in acid soil, whereas other forms, among othersMycogone nigra, Stachybotryssp.,Coccospora agricola (?), and Botryosporiumsp. seemed prominent in neutral soil.2. The vibrios, of which four strains were studied in pure culture, are very sensitive to acidity. They fail to develop in thepH interval 6.0–6.4, and have an optimum atp7.1–7.6.Spirochaeta cytophagaappears to be slightly more resistant to acidity, being able to grow atpH 5.6–6.0.3. The bacteria as well as the fungi are capable of decomposing the lignified cellulose of straw.