The application of some biofertilizers and irradiated compost for replacement of NPK chemical fertilizers was studied on fiveyear-old superior seedless grapevine to determine the best dosage that would improve growth, yield and berry characteristicsand reduce the rates of mineral fertilizations of NPK without any negative effect. The experiment was conducted in a vineyard located at Cairo-Alexandria Desert Road in 2015 and 2016 seasons. The experiment consisted of six treatments, namely, 100% NPK (control), 100% NPK + microbein, 50% NPK + 50% irradiated compost (IC), 50% NPK + 50% irradiated compost + microbein, 100% irradiated compost and 100% irradiated compost + microbein. All treatments were very effective in stimulating growth characters as well as physical and chemical characteristics of the berries in relation to the control tre atment. Petiole NPK %, leaf chlorophyll content and cane carbohydrate content were increased more than the control. In addition, the cluster weight was significantly increased and as a result, yield per vine was increased. The highest superior effect was recorded in response to 100% IC + microbein application. This improvement could be attributed to the positive influence upon the biosynthesis of the primary metabolites (soluble carbohydrates, chlorophyll and carotenoid pigments) and secondary metabolites (proteins, polyphenols, auxins). In addition, both compost especially when irradiated and biofertilizers increase the availability and uptake of N, P and K, which was reflected on the growth parameters. Finally, irradiated compost alone or combined with microbein could be used as a valid alternative method to the expensive hazardous mineral fertilizers.

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