Crop advisers from the across the UK are being approached to help water companies to more effectively manage raw water abstractions, helping to contribute to the cross-industry efforts to prevent metaldehyde from entering reservoirs this autumn.

Talking on the Water UK stand at Cereals 2015, Dinah Hillier of Thames Water explained that, for the treatment works where abstraction management is possible, the theory is simply to respond to a risk of metaldehyde in the watercourses by periodically stopping the intake from the river to the reservoir. “But it’s easier said than done,” she said, emphasising that ‘smart’ abstraction is not a replacement for any of the existing farm-level measures, but rather an additional tool.

“Because of the volumes of water involved, it is actually quite a complex option. The periods over which we can stop abstracting have to be limited, as it’s important to refill the reservoirs after the summer months to provide sufficient water resource for the following year. We also need to abstract during the lower electricity tariff time periods to keep the costs of water production down, and therefore costs to our customers down.

“Ideally we would stop abstraction when we know metaldehyde is in the river and start up again once the peak concentrations have passed. Unfortunately, despite many years of trying, there is still no method for detecting metaldehyde in real-time, and sample collection and analysis doesn’t allow for a quick enough response.”

While a computer model is assisting with weather and soil moisture deficit data to help predict when metaldehyde is likely to reach abstraction points, Dinah outlined that the big piece of missing information is the timing of metaldehyde slug pellet application. “This is where assistance from agronomists is so important,” she said.

David Ellerton, technical development director at HL Hutchison, explained that the Metaldehyde Stewardship Group has been instrumental in coordinating an agronomist recruitment effort, through the AIC (Agricultural Industries Confederation) and AICC (Association of Independent Crop Consultants). Advisers from both organisations are being invited to take part.

“The aim is that around 20 individual advisers will use a reporting system to provide feedback from different geographical areas,” said David. “The initiative will be up and running in advance of the first metaldehyde slug pellet treatments to oilseed rape crops in late summer and continue through the autumn and winter. This is when the majority of slug pellet treatments are applied to commercial crops and when the water companies experience the most problems with exceedances.

“Each adviser will fill in a short report outlining the local soils conditions, weather summary, progress of drilling and crop growth, reporting the metaldehyde treatments that have been applied and that are planned imminently. These reports will be filled in weekly.”
He added that such a service could provide a vitally important bridge between the efforts of the farming and water industries in tackling the issue.

Dinah Hillier noted that abstraction management will never be the whole answer to the issue of metaldehyde in water. “Not all water companies have raw water storage reservoirs, and even those that do, may not have them at every water treatment works. Additionally, the need to supply water will have to take precedence in some years if reservoir levels are low. But, this new reporting system will provide an additional tool available to help in our joint efforts ensure that farmers continue to have future access to metaldehyde based slug pellets,” she concluded.