The mycorrhizal soil infectivity and arbuscular mycorrhizal fungal spore communities in soils of different aged fallows in Senegal

This work was carried out to determine the influence of the duration of fal low and of physico-chemical components of soils on the distribution of endo mycorrhizal fungal spores and the mycorrhizal soil infectivity. The mycorrh ization of indigenous plants from the fallows was examined and it was concl uded that, except for Cassia obtusifolia, fungal colonization was poorly de veloped. No correlation was established between spore populations and durat ion of fallow or between grazed and fenced areas. The relationships between abundance of mycorrhizal spores and the physico-chemical characteristics o f the soils were markedly variable among species of mycorrhizal fungi. The results did not provide evidence of a beneficial effect of increased Length of fallowing on mycorrhizal soil infectivity, but they did demonstrated th e positive effect of preventing grazing on the re-establishment of vegetati on during the fallow period. (C) 2001 Elsevier Science B.V. All rights rese rved.