Fonctionnement Hydrique du Baobab (Adansonia digitata L.) en Moyenne et Haute Casamance (Sénégal) (original) (raw)

This study deals with the baobab's water functioning in order to better understand its water relations with its phenological phases and the effect induced by the climatic seasons and that of the toposequence. For this, the soil moisture, the relative water content (TRE) and the leaf water potential (Ψ) were studied. Data were collected at two sites, in the upland and in the lowland, in the hot dry season (SSC), in the middle of the rainy season (PSP) and in the cool dry season (SSF). SSC corresponds to the appearance of the first leaves. The PSP corresponds to full leafing and the end of flowering and early fruiting. SSF is the advanced ripening of fruits and the full fall of leaves. The R version 3.4.2 software was used to process the data. It allowed to test the data analysis. The results show a seasonal variation ofsoil moisture around the baobab root zone. Indeed, in SSC, soil moisture is at its weakest level, unlike in MSP and SSF. However, the low water availability of soil in SSC does not prevent the internal water condition of baobab from being high. Indeed, succulent trunk deciduous species, Ψ and TRE found baobab are higher in the dry season than in the rainy season. Also, according to the climatic seasons, the differences obtained on Ψ on the one hand, and on the TREs on the other hand, are statistically significant (P <0.05) on the upland contrary to the lowland. The latter benefits from more favorable soil moisture conditions during the dry season, which probably minimized these differences, hence the important role of toposequence on groundwater recharge. These results are important in order to better encourage the spread of baobab plantations through its ability to adapt to the climatic seasons and the environment, and its tolerance of seasonal soil drought, in order to mitigate the degradation of the resource and cope with the effects of climate change.