Growth, Productivity, and Essential Oil Content of Fennel Plants Treated with Spirulina Platensis Extract and Compost Tea Under Low Nitrogen Doses

Abstract The aim of this study was to find alternatives (even partial) mineral nitrogen fertilization reduce its harmful accumulation in the edible parts fennel. Fennel ( Foeniculum vulgare ) is a perennial plant Apiaceae family grown for shoots, leaves, and seeds. present work conducted two successive seasons, 2018/2019 2019/2020, at farm Agricultural Botany Department, Faculty Agriculture, Ain Shams University, Cairo, Egypt, investigate efficiency application biostimulants— Spirulina platensis algae extract (SP) 10% compost tea (CT) 6.72 ml L −1 —with partial doses (75 50%) recommended fertilizer dose on growth, photosynthetic pigments, fruit yield, essential oil productivity. results indicated that vegetative parameters, leaf number, branch shoot bulb fresh weight, dry as well yield components such 100-fruit weight number umbels per were significantly enhanced with SP foliar spray coupled 75% (SP + N) compared other treatments. Photosynthetic pigments total soluble carbohydrate improved when CT applied soil drenching N (CT N). In regard, clear effect noticed terms using dose. It concluded biostimulants only can be economical fennel production.