Relationships between plant-parasitic nematode community, fallow duration and soil factors in the Sudano-Sahelian area of Senegal

The study of the annual changes revealed contradictory tendencies, such as a very small increase in T. gladiolatus and in the soil clay content, which suggest that the sampling technique had probably slightly influenced the results. If this did occur it did not change the effect of fallow duration on the nematode community. The process of decline of certain nematode populations seemed to be extremely slow and not detectable over three successive years. Nematode species were apparently able to reproduce for a long time on poor host plants, even if one plant cohort disappeared abruptly, as was the case when the field was not replanted. This study demonstrated that the soil had a greater influence on the nematode community structure than the annual climatic variations. Consequently, the soil effect will have to be mathematically considered in order to identify the mechanisms by which the plant communities progressively transform the nematode communities.