The aim of this work was to determine the influence of the duration of fallow and of physico-chemical components of soils on the distribution of endomycorrhizal fungal spores and the mycorrhizal soil infectivity. The mycorrhization of indigenous plants was examined and it was concluded that, except for Cassia obtusifolia, fungal colonization was not well developed. No correlation was established between spore population and duration of fallow or between grazed and fenced areas. The relationships between abundance of mycorrhizal spores and the physico-chemical characteristics of the soils were makedly variable among species of mycorrhizal fungi. For the mycorrhizal soil infectivity, the results did not provide evidence of a beneficial effect of increased fallowing but they clearly demonstrated the positive effect of fences on the reestablishment of vegetation during the fallow period