Irrigation scheduling of confectionery groundnut (Arachis hypogeaea L.) in Senegal using a simple water balance model

The sustainability of the groundnut production in North of Senegal hydro-agricultural systems depends on the development of irrigation methods which guarantee yield, quality and meet best water management practices. To achieve this goal, a water balance model taking into account plant development and soil water status was developed. The proposed model expresses evapotranspiration as a function of the observed leaf area index (LAI) and simulated soil water status. Compared to classical tools, mostly based on crop coefficients, the conceptual advantage of the developed model is to take into account not only the impact of water availability on leaf development of the crop but also their incidence on transpiration. Irrigation scheduling consists of determining net irrigation levels by adjusting the fraction of transpirable soil water (FTSW). The model was first calibrated and validated using experiments carried out in 1994, 1996 and 2000, on two groundnut varieties, Fleur 11 and GH 119-20, at the experimental station of Bambey in Senegal, using sprinkler irrigation methods. The model was then applied in 2000 during the dry season to the Senegal river valley under drip irrigation conditions so as to schedule irrigation according to diverse situations of water resource availability. Evidence was made of the model capacity to devise a sustainable irrigation method which guarantees yield, quality and appropriate water management practices.