Effect of C: N ratio on numbers and types of fungi in Egyptian soil.

The amendment of three different soil types [loamy, clay and sandy] with different carbon sources [glucose, cellulose, starch, chitin and sawdust] increased the total count of fungi compared with non-amended soil. Treatment with chitin increased the densities of Trichoderma harzianum. Testing the effect of different C: N ratios [5: 1, 10: 1 and 40: 1] on soil fungi in a loamy soil sample using glucose or cellulose and NaNO3 showed that a narrow C: N ratio was more stimulative to the development of the fungal flora in the presence of glucose. However, a wide C: N ratio was more favorable when cellulose was used as a carbon source showing that sugar fungi and cellulose decomposers responded differentially. Trichoderma was favored by a wide C: N ratio [40: 1] using either glucose or cellulose as a carbon source

Role of cellulose decomposing fungi on azospirillum-maize association

A greenhouse pot experiment and sand cultures were used to examine the possible role of cellulose decomposing fungi in Azospirillum-maize association. Soil amendment with 0.2% straw and inoculation with Azospirillum lipoferum [strain Z 4/1] gave the highest densities of Azospirillum in the histosphere of maize plants and higher growth parameters. Other diazotrophic bacteria of plant free soils were stimulated with a straw amendment. Fifteen genera and 22 species of cellulose decomposing fungi were isolated on cellulose-Czapek's agar medium from pots amended with straw. The total count of these fungi increased significantly with straw amendment. The most common cellulose decomposers were Aspergillus niger, Penicillium funiculosum and Trichoderma harzianum. In sand cultures amended with straw, nitrogenase activity, total nitrogen, residual and straw utilized by co-cultures of Azospirillum brasilense [strain R6/1] and cellulose decomposing fungi were studied