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Composting of onion and other vegetable wastes, with with particular reference to control of Allium white rot. - HL0140LFV

This project has developed a commercial-scale controlled composting process for onion and other vegetable wastes. The composted waste is produced with minimal run-off and odour pollution, and is free of the pathogens, Sclerotium cepivorum and Olpidium brassicae, and pests commonly found in vegetable waste. In addition, the composted waste has a fertiliser value and Allium white rot control activity. Application of the composted waste to white rot infested land has potential to:

• Reduce or eliminate landfill and associated costs
• Reduce fungicide usage and the length of crop rotations currently needed to avoid build-up of the white rot pathogen
• Return onion growing land currently infested with Allium white rot to onion production
• By these actions, address the DEFRA priorities of promoting sustainability in UK Agriculture

Background and Objectives

Loss of the best onion growing soils due to white rot infestation has forced onion production into areas with less suitable conditions for growing high quality onions, increasing the need for transport to centralised packing and storage sites. The accumulation of onion waste in these areas poses a risk of infestation and contamination from crop pests and pathogens, as well as a source of odour and run-off pollution. Landfill disposal of such waste is becoming increasingly expensive. One possible solution is for composted onion waste to be returned to the field providing it is pathogen free. Previous on-farm experiments (Oldershaw, pers. comm.) have indicated that windrow composted onion waste applied to fields may eliminate white rot sclerotia from infested soil. Onion waste contains compounds capable of inducing the sclerotia of the white rot pathogen, Sclerotium cepivorum, to germinate, and germinated sclerotia are unable to survive in the absence of a living host. Composted onion waste could, therefore, provide a means to clean-up white rot infested land.
The objectives of this project were to:

1. Develop controlled composting systems for onion and onion-based vegetable wastes in the laboratory

2. Determine conditions required to eliminate pathogens and pests from laboratory-scale composting systems

3. Determine conditions required to retain white rot sclerotia stimulant activity and the effect of composted vegetable waste on sclerotia viability

4. Quantify the effects of controlled composted onion-based wastes on white rot control, sclerotia survival and onion growth in pot tests

5. Carry out large-scale (20 tonne) controlled composting of onion and onion-based vegetable wastes in bulk tunnels

6. Quantify the effects of rate, storage and timing of application of composts produced in bulk tunnels under controlled conditions on white rot control, sclerotia survival and onion growth in field tests
Project Documents
• Executive Summary : Composting of onion and other vegetable wastes, with with particular reference to control of Allium white rot.   (452k)
Time-Scale and Cost
From: 1999

To: 2001

Cost: £186,001
Contractor / Funded Organisations
Horticulture Research International
Sustainable Production              
Fields of Study