Reuse of olive wash water in agriculture as a biofungicide
Olive mill wastewater is a major environmental problem due to its high organic load, phytotoxicity and antimicrobial properties. There is an opportunity to use it as a fungicide and bactericide.
Waste water from olive mills generated during the extraction of olive oil by traditional milling and pressing processes is considered to be an agro-industrial by-product rich in phenolic compounds. The quantities and physico-chemical characteristics depend on the used oil extraction system, the olives and the operating conditions.
95% of the world's olive oil production produces olive mill wastes that have become a serious environmental problem, due to their high chemical oxygen demand and organic load, and because they resist biodegradation due to their high content of phenolic compounds. The phytotoxic and antimicrobial properties of olive mill wastes have been addressed as a negative attribute limiting the beneficial reuse of olive mill effluents. The valorisation of olive mill wastes is certainly more desirable than their treatment, which is usually applied with destructive methods with respect to their phenolic compounds.
The solution proposed is to used this as an addition to irrigation water. The accumulation of phenolic compounds, quinones and other compounds in plants affected by pathogens positively helps to reinforce the defence and resistance mechanisms against fungi, bacteria and other micro-organisms. Plant disease verticillosis, caused by Verticillium dahliae, is one of the most destructive plant pathogenic diseases known worldwide. Irrigation of agricultural fields with this water has proven to be an eco-friendly alternative for the protection of crops against V. dahliae.
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