Over cultivating seedbeds could cause soil capping and increase the risk of pesticides reaching watercourses during heavy April showers, the Voluntary Initiative has warned growers.

While the dry start to the year has reduced the risk of pesticide residues in surface run-off from wet fields, dry soils can still pose a risk, said VI manager, Patrick Goldsworthy.

“Growers need to be vigilant rather than complacent. Avoid overworking seedbeds – fine seedbeds are more likely to cap causing surface water-logging and faster run-off, so leave them slightly cloddy.

“Last year Environment Agency data showed there had been a 19% improvement in surface water, we need this ‘attention to detail’ to ensure good progress by UK farmers continues.”

Digging up soil samples across a field can help identify high risk zones with poor structure, added UK Soil Management Initiative’s Paddy Johnson. “The presence of poor seedbeds, or those that are difficult to create, tends to be a sign of poor structure.”

Before spraying, growers should check soil moisture status, drainage and weather forecasts to decide if applications will be safe and effective, said Mr Goldsworthy. If drains are running, or likely to run due to imminent heavy rainfall or showers, spray application should be delayed, he advised.

Key soil risk factors:

  • Slopes
  • Surface capping or compaction
  • Shallow panning
  • Light soils – loamy sands to sandy loams
  • Cracked heavy soils

Step-by-step advice on the decision-making process is available in the VI’s spring herbicide decision trees – see www.voluntaryinitiative.org.uk