Science into Practice: Soil sterilisation with novel steam machine

As the use of methyl bromide -- the soil sterilant of choice for years -- has been phased out in the EU, it has become imperative to find efficient, cost-effective ways of disinfesting soils.

A prototype soil steaming machine has been developed as part of CP 6, a LINK/HDC project. Steam is an exceptionally efficient method of heat transfer, which is why it is used to sterilise surgical instruments in hospitals.

High-pressure soil steaming machines have been manufactured but they are slow, heavy and require huge amounts of energy — plus they don't disinfect to depth.

The project developed a novel method of generating low-pressure steam in which thin films of water are passed close to burning fuel. Tests determined the minimum temperatures needed to control a range of soil-borne pests, diseases and weed seeds. A threshold of 70 degsC was sufficient to control all weed seeds, fungal pathogens and potato cyst eelworm.

A prototype was successfully designed and trialled on a range of soil types. Based on a potato de-stoning machine, the soil is lifted onto a conveyor and subjected to an upward flow of steam from an efficient electric steam generator. The machine was field tested at seven sites ranging from Sussex to Inverness on a range of crops including carrot, baby leaf spinach, iceberg lettuce and onion.

The steaming machine proved capable of operating in a wide range of soil types and moisture conditions. Weed control was very good on some sites. The steam treatment also resulted in improved crop vigour. This was probably due to increased nitrogen mineralisation caused by the steam, potentially reducing the need for fertilisers.

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

What is being done to develop biocontrols against orchard pests?

What is being done to develop biocontrols against orchard pests?

The SIVAL horticultural trade show in Angers, France, this week (16-18 January) heard about several initiatives to promote more environmentally sustainable orchard growing.

What does the 25-year plan mean for growers?

What does the 25-year plan mean for growers?

Published on 11 January, the Government's long-awaited 'A Green Future: Our 25 Year Plan to Improve the Environment' brings together a number of policy strands into a single framework that will impact many sectors, not least fresh produce, over the coming decades.

What will 'embracing change' mean for horticulture?

What will 'embracing change' mean for horticulture?

At the Oxford Farming Conference, whose theme was "embracing change", Defra secretary Michael Gove expanded on what a post-Brexit UK agriculture and land-use policy will look like and how it will impact farmers and growers.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Professor Geoffrey Dixon

GreenGene International chair Geoff Dixon on the business of fresh produce production

Read Professor Geoffrey Dixon