CONVERTED OLIVE MILL WASTES TO COMPOST TEA WITH BIOLOGICAL TREATMENT AND ITS IMPACT ON GROWTH AND PRODUCTIVITY OF MANZANILLO OLIVE TREES
June 2017 (link here)
What happens when you apply compost tea, made from olive waste compost, back on to olive trees? Great question huh? It's what a group of Egyptian researchers at Cairo University's Agricultural Research Center asked as they embarked on another adventure in organic agriculture!
The researchers made compost with the leftovers from olive production, mainly olive pomace (waste material after pressing olives for oil). Along with the compost, the researchers wanted to see if they could make use of "olive vegetable water" (another waste product of olive oil production) as a fortifying ingredient for their tea. They made several batches, with and without olive water, and some with added beneficial microbes. They then aerated the compost/water/microbe mixtures in order to make them into true compost teas. The researchers then applied the teas at different rates to a selection of tester Manzanillo olive trees in an orchard, some 20 miles northwest of Cairo. The tea was watered into the soil twice a week for four months. Growth response of the trees, as well as quality and characteristics of the olive yields were measured and analyzed.
Incredibly, the scientists found that all trees that received any compost tea performed significantly better in regards to: the highest shoot length, number of leaves, fruit diameter, flesh/fruit weight, flowering density, perfect flower %, fruit set %, yield, olive oil content, leaf nitrogen and potassium content as well as the highest net profit. Though all tea treatments were effective, though the most efficient and net-profit maximizing treatment was: compost tea at the rate of 50% plus 50% olive vegetable water and added beneficial microorganisms.
Using compost tea in a production system makes perfect sense. Waste streams are turned back into valuable resources. Hats off to the Manzanillo olive enthusiasts pushing our collective knowledge onward into a sustainable future.