Résumé
Rice is a major strategic commodity in Senegal government's options, it accounts for 34% of national cereal consumption; from which 50% of cereals consumed in urban areas and 24% in rural areas. In Senegal, rainfed rice grows under lowland and upland conditions. Recently, the government create incentives to increase upland rice yield as it might have a huge impact on smallholders that depend on rice production and don't have resources to convert to irrigated systems (Projet d'Appui à la Production Durable du riz pluvial (PRIP) maer.gouv.sn)). Upland rainfed rice has also the potential to be integrated into sustainable cropping systems with less environmental impact and better resilience to shocks than lowland rice. In upland rainfed rice, farmers could plant a rice crop in rotation with other crops; therefore, rainfed rice could become a key component for regional food security in West Africa. In Senegal, there is a huge unexploited land particularly for expansion of rainfed upland rice as only 20% of the area potentially cultivated has been exploited (Villar et al, 2019). However, the promotion of upland rice system has not been successful due to several constraints such as inadequate water availability, poor soil, suboptimal crop management and biotic stress (Saito et al 2018) as well as lack of sufficient knowledge of appropriate varieties and good agricultural practices. Recent field surveys showed socio economic constrains that could explain the low deployment of rainfed rice in Senegal (lack of adapted varieties, mechanization and fertilization) but also showed the importance of rainfed rice for food security. In general, rainfed rice is grown on a small plot with an average of 0.4 ha and 0.27 ha for male and woman farmer, respectively (Direction de l'Analyse, de la Prévision et des Statistiques Agricoles, 2020). It is cultivated in a single season during the rainy season, which covers generally 5 months, from June to October. Rainfed rice remains primarily for home consumption and covers rarely 50% of the household's family needs. In order to determine the potential areas for upland rice depending on the biophysical and socio economic constrains a literature review and socio economic surveys were performed. The literature review identified key regions and data available for crop modelling studies for upland rice in Senegal. It gathered data for a total of 15 sites with lowland rice trials and 38 sites with upland rice trials. Most of the trial sites were in areas that experience high levels of climate variability, high temperature stress and drought. Using annual average data for precipitation and temperature for the 38 sites three potential environments for upland rice were identified: A dry environment with 648 mm.year1precipitation, a wet – cool environment and a wet-hot environment both with 1000 mm.year1. Further analysis will allow us to identify if the classification of trials sites reflects the yield response of upland rice varieties; and then map areas according to their climatic risk. In fact, taking as an example the success of upland rice in the north of Brazil, we suggested some studies that could be performed to estimate the potential of the upland rice region in Senegal.