Biological studies of some tussock-grassland soils

Abstract

The fungi occurring in three soils, under low-tussock grassland, were examined at various seasons, employing screened immersion plate, soil plate, and rhizosphere and root plating, techniques. Approximately 100 species were isolated. The screened immersion plate method showed that: (a) the three soils were of similar mycelial status; (b) maximum growth was obtained in summer; (c) non-sporing fungi, including Rhizoctonia sp. and Papulaspora sp., accounted for approximately 60 % of all isolations from the three soils; (d) Rhizoctonia sp. dominated all three soils. Soil fungal pattern, based on percentage frequency of occurrence, are shown for the three soils. The broad relationships of the soil fungal floras reflect, generally, the broad relationships between the vegetations and between the soils. Fungal isolations by the soil plate method differed from screened plate isolations, particularly in the absence of Rhizoctonia sp. Rhizosphere platings from tussock plants gave similar results to soil plate isolations. Platings of tussock plant roots were dominated by Trichoderma viride and by members of the Mucorales. It is suggested that the soil fungal populations are greatly influenced by the higher-plant roots.