LINK OF VEGETATION WITH SOIL AT A FEW METER-SCALE - HERBACEOUS FLORISTIC COMPOSITION AND INFILTRABILITY IN A SUDANIAN FALLOW-LAND

The link between vegetation and soil at a few meter-scale was studied in an old physiognomically homogeneous fallow-land (over 30 years) of anthropic Sudanian savanna with poor tree cover. Sampling was conducte d systematically on a 60 m x 60 m surface, following a five-metre grid . Floristic releves were made in quadrats (1 m x 1 m), in each corner of which infiltrability was measured by a method derived from the sing le-ring infiltrometer. Seventy four herbaceous species are present; th e 156 releves could be classified in seven floristic units, which have a dear link with the soil hydropedological characteristics at a few m eter-scale. Among the 18 main species (present in at least 10 % of the 156 releves) only four could be considered as indifferent to infiltra bility, another eight preferred relatively high infiltrability microsi tes, and the last six preferred poor infiltrability microsites. The re latively high floristic richness of the site can be partly explained b y the aptitude of various species to exploit one or another of the dif ferent microsites available. The results also suggest a certain struct ural and functional redundancy between species. (C) Elsevier, Paris.