Converted Olive Mill Wastes to Compost Tea With Biological Treatment and Its Impact on Growth and Productivity of Manzanillo Olive Trees

Abstract

The current study has been carried out through two successive seasons (2013 and 2014) on 12 years old Manzanillo olive trees in a private orchard located 50 km of Cairo-Alexandria road in the north west of Egypt. The main objective of this study was to convert olive mill wastes [pomace and olive vegetable water (OVW)] to compost tea (CT) and studying their effect on growth and productivity of olive trees. Compost tea (CT) was prepared by soaking the mixture of compost and olive pomace (2:1) in either water or the combination of water with olive vegetable water at different rates (25% or 50%). Four microorganisms (Serratia marcescens, Pseudomonas fluorescens, Phanerochate chrysosporium and Trichoderma virdi) were used in preparing compost tea. Data exerted that the treatment with CT + microorganisms gave the highest shoot length, number of leaves, fruit diameter, flesh/fruit weight. While, using the mixture of compost tea (50%) and olive vegetable water (50%) and incubated with microorganisms recorded the highest leaf area, flowering density, perfect flower (%), fruit set (%), yield, olive oil content, leaf nitrogen and potassium content as well as the highest net profit. Thus, it could be recommended, under the same conditions of this study, to use converted olive mill wastes to compost tea (CT) at the rate of 50% +50% olive vegetable water (OVW) + microorganisms to increase the productivity of Manzanillo olive trees and the net income, which in turn reduces the amount of fertilizer and environmental pollution caused by these wastes.