EFFETS DES APPORTS DENGRAIS MINERAUX SUR LA CROISSANCE, LA PRODUCTIVITE ET LA RENTABILITE ECONOMIQUE DU SESAME DANS LE CENTRE SUD DU NIGER

Sesame (Sesamum indicum L.) is an annual oilseed crop cultivated for its seeds which are a source of income and nutrients for farmers. In Niger, the plant is mainly cultivated on low inputs soils some often without added fertilizers because sesame is considered as secondary crop. A study of the response of sesame to mineral fertilization was carried out on the experimental farm of the Faculty of Agronomy and Environmental Sciences of Dan Dicko Dankoulodo University of Maradi during the rainy season 2019-2020. The SN-103 cultivar was used in a split-plot design set-up with 4 replicates. Two factors were studied : the type of fertilizer with two levels (15-15-15 and 18-46-00) and the dose at five levels (0 kg ha-1 (control), 80 kg ha-1, 300 kg ha-1, 334 kg ha-1, 368 kg ha-1). Flowering time, plant height at maturity, the number of capsules per plant, the number of branches, the grain yield and the Normalized Difference of the Vegetation Index (NDVI) were the parameters monitored. The economic benefits analysis of applying these doses were also carried. The results evidenced that there is no significant difference between the two types of fertilizer in their effects on the growth and the development parameters and that only the dose effect was significant. Higher dose of 15-15-15 or 18-46-00 significantly increase the grain yield of sesame. The rate of 368 kg ha-1 was particularly more productive with a grain yield of 837 kg ha-1. The two doses of 80 kg ha-1 and 368 kg ha-1were economically superior and stable within the price variability periodes of sesame grains. NDVI 4, measured on the 66th day after sowing, alone explains 63,30% of the variability in sesame grain yield. Although sesame is considered a less fertilizer demanding crop, it responds well to fertilization and a measured NDVI during full bloom can be an effective tool for predicting sesame seed yield.