The ecology of soil fungi

Abstract

The influence of soil type and soil horizon on the distribution of microfungi in five natural grassland soils at Lakenheath Warren has been investigated. The soils, which are all very dry and sandy, vary from a shallow, highly alkaline soil to a deep, highly acid podsol. One hundred and forty-eight species of fungi have been isolated from these soils by the soil-plate method.The most common genera are Penicillium and Mortierella , followed by Absidia, Cephalosporium, Fusarium, Gliocladium, Gliomastix, Mucor, Thielavia, Trichoderma and Zygorrkynchus . The occurrence of fungal species in twenty profile samples of each soil has been recorded, and the distribution of the more important species is discussed in detail. It has been shown that the number of fungal species and colonies in a profile falls off with depth, the rate of reduction being dependent on the depth of the soil and the nature of the soil horizons. Most species occur most abundantly in the surface layers of the soil. A few species were commoner in subsurface layers, and a few were abundant near the chalky boulder clay of the C horizons. Fungi show different distributions in the five soils, and two large groups may be distinguished: those common in the acid soils and those common in the alkaline soils. Species of Penicillium were particularly abundant in the acid soils. Microscopic examination of soil has shown that fungi are present both as spores and mycelium. Study of incubated soil plates stained with lactophenol cotton blue has shown that most of the colonies develop from humus particles. Viable spores have also been found in these soils, especially the acid ones.