Influence of Two Native Shrubs and Fertilizer on Crop Growth and Yield in Peanut Basin of Senegal.

In the semi arid zone shrubs coexist with crops on farms. Several studies have shown that the presence of shrubs significantly improves fertility, soil water status and crop yields, with little information on crop growth. Therefore the objectives of this study were to determine the effect of the presence or absence of shrubs under different fertilizer rates: (i) crop phenology and growth and (ii) crop yield. Experiments were conducted in the north and south peanut Basin of Senegal where the shrubs Guiera senegalensis and Piliostigma reticulatum dominate, respectively. Experiment plots were in split-plot design with two factors. The presence or absence of shrub is the main factor and the level of fertilizer (0 and 150 kg ha^-1 N-P-K) as a secondary factor. Results showed that the presence of shrubs has increased significantly crops growth parameters than no shrub plots (P<0.05). In the northern site which is drier (450 mm annual rainfall mean); crops growth has been accompanied by the earlier appearance of phonological stages and crops yield in shrub with no fertilizer were statistically similar to no shrub with fertilizer. However, in the southern site where annual rainfall ranges from 600 to 800 mm, fertilizer seems to be the main factor to increase significantly crops yield. But crops phenology and growth were not significantly different between shrub with no fertilizer and no shrub with fertilizer.This study has shown that the combination of shrubs with crops like an agroforestry system has many advantages. In vulnerable ecosystems where natural resources are continuously degraded, intercropping with shrubs appears to have an overwhelmingly positive impact on crop yields, especially in plots with no fertilizer additions.