Effect of Yeast and Different Phosphorus Fertilizer Sources on Growth and Fruiting of Balady Mandarin Trees

This investigation was carried out in the experimental orchard, Faculty of Agriculture, Assiut University, Egypt, to study the effect of soil inoculation with yeast or phosphorin (P- dissolved bacteria) only or combined with 50 or 25% mineral-P on growth and fruiting of Balady mandarin trees during 2011, 2012 and 2013 seasons. Calcium superphosphate was applied once in December.  Yeast and phosphorin were applied once in March followed by the trees were irrigated.
The obtained results were summarize as follow:
-  Using yeast or phosphorin as bio-fertilizers only or combined with 50 or 25% of the recommended phosphorus dose (RPD) significantly increased the shoot and leaf traits.
-  Leaf content of chlorophyll and nutrient elements as well as the total carbohydrates and C/N ratio of shoots were significantly increased due to use of either yeast or phosphorin singly or combined with phosphours at 50 or 25% of RPD compared to use the RPD via mineral-P source alone (check treatment).
-  Yield components and fruit quality was significantly improved due to use of either yeast or phosphorin, singly or combined with either 25 or 50% of RPD compared to use mineral-P only.
Using yeast or phosphorin only or combined with 25% mineral-P was very effective in improving the growth and fruiting of the trees.
Moreover, using yeast was superior in improving the yield and fruit quality than using phosphorin, where, using yeast at 200 ml/tree gave the best results.
It is evident from the foregoing results that using yeast either 200 ml/tree only or yeast at 150 ml plus 25% of RPD as mineral-P as well as phosphorin either 400 ml/tree only or phosphorin at 300 ml with 25% of RPD as mineral-P improve the superphosphate use efficiency through increasing the P availability and consequently, decreasing the amount of applied phosphatic fertilizer and reducing both the agriculture cost and the pollution impact of superphosphate