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Strategic trials managing slug control and water quality

The relationship between arable crop protection practices, the UK’s number one crop pest and the maintenance of water quality in catchments, is something the water companies are taking steps to improve and manage.

Field adjacent to watercourse

The relationship between arable crop protection practices, the UK’s number one crop pest and the maintenance of water quality in catchments, is something the water companies are taking steps to improve and manage.  

Slug control and water quality has always been a contentious issue, and it remains a top priority to find and develop solutions to managing slugs without traces of metaldehyde reaching watercourses.

Severn Trent has set up a number of innovative trials in various catchments this autumn, targeting an assortment of methods to manage water quality in line with slug control practices, explains Katherine Cherry, Severn Trent’s Catchment Management Planner.

“We are looking at four contrasting trials, working closely with the National Farmers Union, Catchment Sensitive Farming and the Environment Agency. The ultimate goal is to find a workable solution for the industry as a whole that is practical, cost effective, and won’t negatively impact the water quality in our catchments.”

The first trial, ‘Farmers as producers of clean water’ let’s farmers decide how best to work together and is an interesting approach, comments Katherine. “Farmers’ will decide how they can positively impact water quality through responsible pelleting or the use of alternatives. The aim is to reduce the concentration of metaldehyde in the Didgeley Brook (Warwickshire), a small tributary which feeds into the River Bourne from which drinking water is abstracted. The brook has previously shown some very high peaks in metaldehyde levels.”

William Antrobus and his family are farmers who are heavily involved in this trial with Severn Trent. “I have a history of working in sprayer proficiency testing, so the opportunity to work with the water company to drive responsible use of pesticides was very attractive,” comments William.  

“We invited all the local famers in the catchment to a meeting and we subsequently got over 90% buy in to the trial. Being based only four miles from the drinking water reservoir, it’s an issue that is very close to us; we felt it was worth being involved as we have always been responsible with pesticides.

“Our agronomist advised we used Sluxx (ferric phosphate).” William adds, “It’s reassuring there is a slug pellet out there that delivers on all counts of efficacy and the environment,  that I can use on my crops while ensuring there is no detrimental impact on the water quality in the brook.”

Katherine goes on to explain about another of their trials currently underway. “On two farms in the Cropston catchment (Leicestershire), a straight field trial is in progress with two products (metaldehyde and ferric phosphate) being used in different fields.”

Various measurements are being taken, including water samples from field drains for laboratory testing, as well as the monitoring of crop damage by slugs. This is to allow us to measure the water quality benefits of alternative slug controls and provide assurance of their efficacy.

The third trial, where farmer engagement is key is based around a zero metaldehyde area in the Staunton Harold catchment (Derbyshire). “In this case product substitution is being encouraged for all farmers in the area, and catchment officers have spoken with local agronomists so their advice to farmers will be in line with the purpose of the trial.” A 3% ferric phosphate was selected by the majority of the farmers.

Certis have been instrumental in working with Severn Trent to get farmers involved in the field trial set up with ferric phosphate pellets, comments James Kennedy, Certis’ Account Manager. “The use of ferric phosphate has been embraced here and nationwide.”

He goes on to add, “Fields that border a watercourse or where drains are obviously flowing, are a perfect example of where to use a ferric phosphate pellet. It allows farmers to continue to protect crops from slug damage when it is not advisable to use other actives, as there is a high risk of causing exceedances.”

Severn Trent is also investigating ways to manage their own operational practices to improve water quality, adds Katherine. “We are undertaking an intake management trial to see the difference from drawing water from certain sources during a low risk period, compared to turning the pumps off at high risk times. The aim is to improve the quality of water arriving at our treatment works.

“The scale and variety of the trials is designed to give us tangible, evidence based results that will allow us to make workable suggestions while working alongside farmers to reduce exceedances from occurring. We want to keep it simple and reliable for farmers,” she says.   

The full results from the trials are expected in the New Year, notes Katherine.

“We are planning for the future; by working alongside farmers, agronomists and commercial companies within the industry like Certis. We aim to get practical results and advice that won’t hamper crop production.”