Water Protection Advice” booklet giving guidelines for farmers on safeguarding water from crop protection products has been published by The Voluntary Initiative (VI).

Modern, profitable farming depends on a range of effective crop protection products, which are declining mainly as a result of legislation. More products may be at risk as the Water Framework Directive starts to bite.

Oilseed rape is a good example of the problem faced by arable farmers. The crop is dependent on four herbicides, which together with metaldehyde slug pellets are vital to the viability of the crop and blackgrass control across rotations.

Slug control is essential for good crop establishment which can be reduced by 15% by the pests. Without effective weed control on soils where blackgrass is a major problem gross margins could fall by £390/ha. With average overheads on an arable farm running at around £450/ha a farm suffering such losses would not be profitable.

Unfortunately, all the active ingredients in these essential crop protection products have been detected in water, sometimes at levels well above the stringent 0.1microgramme, litre set for drinking.

“This booklet brings together practical advice for farmers on how to prevent pesticides causing diffuse water pollution, which can cause ecological harm and affect drinking water quality, with clear guidance on use of the pesticides that are being detected in water,” said Philippa Mansefield of the England Catchment Sensitive Farming Delivery Initiative (ECSFDI).

The VI has been working to identify ways to minimise pesticide movement to water either from filling and handling areas, through field drainage or from surface run-off. The booklet provides a list of priority catchments where extra vigilance is required, sets out best practice guidelines for all pesticides and highlights extra measures that apply in priority catchments.

“A key part of the new advice is to establish grass buffers beside any watercourse,” explained VI manager Patrick Goldsworthy. Evidence to date, from both the UK and elsewhere in Europe, suggests that grass buffer strips – at least 6m wide – will reduce surface run-off by at least half.

“In addition, herbicides should not be applied when soils are saturated and drains are flowing and applications should be made at least 48 hours before any heavy rain is expected.

“As oilseed rape has been identified as a key crop where winter applied herbicides are being found in surface run-off we suggest that growers establish buffer strips. These strips should be established in the year before oilseed rape is grown. However, it is better to establish these strips this autumn rather than do nothing.”