Enhancement Yield, Fruit Quality and Nutritional Status of Washington Navel Orange Trees by Application of Some Biostimulants

The effect of some biostimulants [potassium humate, yeast extract and amino green II (amino acids mixture)] on yield, fruit quality and nutritional status of Washington Navel orange trees was evaluated. Potassium humate was applied at 10 and 20 g/tree as soil application. In addition, yeast extract at 0.2 and 0.4% and amino green II at 0.25 and 0.5% were applied as foliar application. The obtained data revealed that all biostimulants increased total yield compared to control. The highest yield was obtained with trees received potassium humate at 20 g/tree. Fruit weight, fruit juice %, total soluble solids (TSS), total sugars and vitamin C. contents markedly increased with biostimulants treatments compared to control. Moreover, high values of such characters were obtained with trees treated with potassium humate at 20 g/tree and active dry yeast at 0.4%. Biostimulants treatments enhanced leaf chlorophyll content and leaf mineral contents of N, P, K, Ca and Mg. Generally, it can be concluded that biostimulants treatments had a positive effect on yield, fruit quality and nutritional status of Washington Navel orange trees. In this respect, potassium humate at 20 g/tree and active dry yeast at 0.4% were considered the promising treatments.