Effect of Organic and Bio-Fertilizers as a Partial Substitute for NPK Mineral Fertilizer on Vegetative Growth, Leaf Mineral Content, Yield and Fruit Quality of Superior Grapevine
This study was carried out during the three consecutive seasons of 2009, 2010 and 2011 in sandy soil at 64 kilometer from Cairo on the desert road to Alexandria on ten years-old “Superior Seedless” grapevines to study the possibility of using the organic and bio fertilization partially instead of completed mineral fertilizers as applied at 25 to 100 % out of the recommended NPK rate. Organic fertilizers (compost) plant residues with two natural rocks, rock phosphate and feldspar were applied with or without biofertilizers (biogen, phosphorin and potassiumag) at 30g/vine. The results indicated that application of 50% (compost, rock phosphate and feldspar) + 50% of the NPK mineral recommended fertilizers N (157 g/vine), P2O5 (87 g/vine) and K2O (112 g/vine) + bio-fertilizer was the best management system for ensuring the best vegetative growth parameters as shoots length, number of leaves/shoot and leaf area and leaf mineral content and achieving the best yield with its components as number of clusters per vine and weight of each individual cluster, improving the physical and chemical characteristics of berries as total soluble solids, total acidity, TSS/acid ratio and total sugars, but reducing nitrate and nitrite content of berries of Superior Seedless grapevines. Therefore, these organic and natural rocks fertilizers in combination with NPK bio-fertilizers can reduce the need for about 50% of NPK mineral fertilizers. In addition, minimized the production cost and the environmental pollution which could be occurred by excess of chemical fertilizers.