Abstract
The excessive use of nitrogen fertilization increases soil acidity, and contaminates the environment. It also increases heavy metals concentration in the plant with a serious threat to human health. A wide variety of microorganisms can be used as alternatives to minimize mineral fertilization. This study was conducted during the 2017 and 2018 seasons on 'Sewi' date palm grown under Egyptian conditions, to evaluate the effect of mineral-, organic-, and bio-fertilization on fruit yield and quality, as well as to encourage growers to switch to organic-and bio-fertilization. Fertilization was applied in six treatments; 1) 100% mineral NPK, 2) 100% manure, 3) 100% Azotobacter chroococcum [Az14], Bacillus megatherium var. phosphaticum [B6], 4) Bacillus circulans [B4]), 5) 50% manure + 100% bio-fertilizer, and 6) 50% mineral NPK + 100% bio-fertilizer, plus the control (no fertilization). Results indicated that 50% manure + 100% bio-fertilizer and 50% NPK + 100% bio-fertilizer improved yield and fruit quality. Fertilization with 50% manure + 100% bio-fertilizer led to high values of leaflet area, yield, fruit and flesh weight, soluble solids content, vitamin C, and total sugars, but the lowest fruit firmness. While 50% NPK + 100% bio-fertilizer led to the highest values of new leaves, leaf length, fruit length and diameter, and reducing sugars. Results indicated that non-mineral fertilizers improved yield and fruit quality compared to the mineral ones, and this was also more acceptable to the consumers.