More still has to be done to understand the nature and effects of diffuse pollution caused by potato production, says Derek Knight, Catchment Sensitive Farming officer for east Yorkshire and north Lincolnshire.
"Potatoes are prone to soil and water-related problems, but they can be managed and minimised, and there are real positive benefits for those growers who achieve this."
The Water Framework Directive's aim to have all waters in "good ecological status" by 2015 was driving the need to address the issue and all growers, not just those in the Environment Agency's 40 priority catchments, should follow best practice.
Added pressure would come from the introduction of an Environmental Liability Directive, which was being discussed by government at present (see box).
Soil erosion and nutrient leaching were the two areas to focus on, Mr Knight said. "Select free-draining soils and avoid planting on slopes. If you do have slopes, try to plant across the slope - it's not always easy to do and can worsen the situation if you don't get contour planting right."
Growing potatoes on sloping fields could become a thing of the past in some areas where soil erosion is a regular occurrence
Nutrients, whether artificial fertiliser or manures, had to be better targeted to what the crop needed and what was already in the soil, he said. "You have to make sure you are using soil analysis and getting applications right. It's especially important to take account of exactly how much P and K is in manures."
Managing headlands to reduce compaction would also be important and buffer strips or stewardship margins at the bottom of slopes could prevent run-off (carrying soil and nutrients) getting into watercourses.
"Establishing cover crops pre- and post-potato crop will become more pertinent, particularly with the new [tighter] NVZ rules that might be introduced pretty soon."
In some extreme cases, where fields regularly suffered erosion problems and heavy run-off, he suggested potato production may have to stop and fields put down to other lower-risk crops, or even grass.
Action to take
- Ensure cross-compliance rules are observed
- Complete management plans
- Carry out a risk assessment for each potato field before planting
- Apply appropriate mitigation measures
- Consider using environmental stewardship options to tackle problems
- Contact your local CSFO to find out the local priorities - arrange a one-to-one visit
Environmental Liability Directive
- Aims to prevent and remedy environmental damage (principally covers habitats and protected species, water resources, land contamination)
- Based on the "Polluter pays" principle
- Two public consultations planned - the first was completed on 28 February 2007
- Consultation on draft regulations planned for early 2008
- See http://www.defra.gov.uk/environment/liability/#5
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