This study was conducted during the two successive winter seasons of 2004 /2005 and 2005/ 2006 at the Experimental Farm of Faculty of Agriculture ,Moshtohor, Benha University to investigate the effect of nitrogen, phosphorus and potassium fertilizers as well as rizobacterin and phosphorein biofertilizers on plant growth, chemical constituents, yield and its components, quality and storageability of garlic bulbs (Allium sativum L.) cv. Balady. The obtained results revealed that garlic cloves treated with rizobacterin and phosphorein as mixture or each of them separately in the presence of half recommended doses of chemical NPK fertilizers (60 kg N, 38 kg P2O5 and 48 kg K2O/ fed) significantly increased the studied characters compared to untreated plants in both seasons. However, the application of rizobacterin plus phosphorein combined with 60 kg N, 38 kg P2O5 and 48 kg K2O/ fed gave the best results of growth parameters (plant height, numbers of leaves, fresh and dry weight per plant and bulbing ratio), plant minerals contents (N,P and K%), bulb yield and its components (average bulb diameter, fresh weight, number of cloves per bulb, clove fresh weight and total as well as relative yield/ fed), moreover bulbs quality (N,P,K,TSS, total carbohydrates and volatile oils content) in both growing seasons. Fertilization of garlic with 120 kg N, 76 kg P2O5 and 96 kg K2O/ fed recorded maximum values of weight loss percentage in bulbs during storage in comparison with the treatment of rizobacterian and phosphorein mixture and/or every one separately in combination with 60 kg N, 38 kgP2O5 and 48 kg K2O/ fed which gave the lowest values in this respect.
Therefore, application of 60 kg N, 38 kgP2 O5 and 48 kg K2 O/ fed plus mixture of rizobacterin and posphorein could be recommended as the best treatment for raising garlic yield, improving bulb quality and to reduce the amounts of NPK fertilizers by 50% of the recommended dose.