Effects of foliar application with compost tea and filtrate biogas slurry liquid on yield and fruit quality of Washington navel orange (Citrus sinenesis Osbeck) trees

Abstract

Sixteen-year-old navel orange trees at a private orchard located in Kafer El-Sheikh Governorate, Egypt, were used in this study. Compost tea (CT) and filtrate biogas slurry liquid (FLB) were applied at two different concentrations (50% and 100%); control trees were sprayed with water. Trees treated with CT at 100% were the highest in yield, fruit weight, and vitamin C, whereas the highest percentage of fruit set, fruit number, and soluble solid content (SSC), lowest fruit drop, and highest reducing and total sugars were in trees treated with 100% FLB. Concentrations at 50% for both foliar application (CT and FLB) improved yield and fruit characteristics than control treatment. Generally, using a foliar application of compost tea and filtrate biogas slurry liquid at (100%) treatments as food nutrients could be recommended to improve the yield and fruit quality of navel orange fruits under the current study conditions. Implications: Consequently from the previously mentioned results, it was clear the great role of compost tea (CT) and filtrate biogas slurry liquid (FLB) as two sources of foliar application of organic fertilization for Washington navel orange grown in a clay loamy soil, as they are indispensable for improvement of the nutritional status of the navel orange trees and production of maximum yield and quality of orange, as well as minimizing the cost of production and in turn increasing the income of orange orchard. So, it should be recommended the superiority of application of FLB and CT, especially 100%, which gave the best results in yield and physical and chemical characteristics of navel orange fruits.