Between turf and a hard place

Jane Carleyin Weed Control

The ongoing dilemma between presenting to high standards and addressing stakeholders' environmental concerns is especially striking when it comes to weed control, and with a range of alternatives coming onto the market, is it time to look at the options?

RootWave Pro is a professional hand weeder

Chemical use in groundcare remains in the spotlight, with consumers on one hand calling for higher standards in the care and presentation of sporting and leisure facilities, but on the other being concerned about products applied to turf and hard surfaces and their impact on human health and the environment.

Amenity Forum Executive Officer Peter Corbett reckons that legislation and industry practice already addresses these concerns, but that the EU's position, which still impacts the UK post-Brexit, looks to go further.

"Pesticides are highly regulated in terms of where they can be used and at what rates. Regulation also covers active ingredients and co-formulations, and how products are applied. But, we're governed by the Sustainable Use Directive, which highlights sensitive areas as anywhere the general public can use or walk across, and it has been proposed by the EU that all pesticides should be banned in urban situations."

Peter acknowledges the challenges, particularly when treating small areas.

"Applications are mainly via knapsack or pedestrian sprayers, where the operator is behind the boom or lance rather than protected by a cab and in front of it, so one issue is operator exposure. However, products that don't meet criteria on exposure have already disappeared from the market. Operator qualifications also offer protection to third parties and the environment."

He suggests that there is already a downward trend in spraying, depending on who runs the facility. Use of selective chemicals on turf is not as high on the political agenda as hard surface spraying, but is also worthy of review, he points out.

"Herbicides are an important part of the management package, but an integrated approach is becoming more significant, using physical, cultural and chemical methods of control. It is good groundsmanship - there is no silver bullet."

Turf is already highly competitive as a crop, and when well managed can hold its own against weeds, he comments. "But, this requires investment in people, equipment and turf nutrition."

He suggests that while stadia pitches have moved on dramatically in terms of quality, unfortunately, at the grass roots end it has gone the other way.

Advances in application technology have had a significant impact, increasing accuracy. "Future developments such as the use of robots and even drones to minimise operator exposure and improve accuracy and timeliness have potential. Legislation still presents barriers, however - aerial spraying is not permitted, yet the knapsack operator is effectively holding the nozzle 'above the ground'."

Peter suggests that operators using best practice can help preserve the future of active ingredients.

"We need to avoid the risk of incidents in public - only spray at the right time and in the right way. But educating the public is also important, to show them what we are doing and why we are doing it."

Amenity Forum chairman Ian Graham is also managing director of leading contractor Complete Weed Control, and he comments that much of the negative perception of glyphosate goes back to the links to former manufacturer Monsanto and its work on genetically modified 'Roundup Ready' crops.

"This has led to pressure on the industry to rethink glyphosate use, but we only now have empirical evidence on the alternatives.

"The cost of alternative methods is significantly higher - hot foam is ten times as expensive as glyphosate. We need to have the research to inform our practices."

Operator exposure is an issue with knapsack spraying, but products that don't meet the criteria on exposure have already disappeared from the market.

Ian suggests that concerns about spraying largely come not from CWC's customers, but from users of the facilities.

"As professionals we listen to advice from decision makers. We use the Pesticide Guide and product labels to inform us on PPE and applications - to make an analogy with medicine, it's not for the doctor to decide if the medicines that are available to prescribe are safe. Instead, as practitioners we're charged with the job of producing playing surfaces. Integrated Weed Management (IWM) is an important part of the approach, defining to what degree weed control is needed."

This is also the case in the urban environment, he adds, where design can help or hinder weed control.

"Regular cleaning to remove detritus can help, and where there are fewer weeds there is a reduced need to use glyphosate."

There are a range of sustainable options to help manage weed populations on hard surfaces, he points out.

"It comes down to what is acceptable - 100% weed control may not be achievable, but an absence of control is equally unacceptable. We need to get a balance, and cost and efficiency is key. Some methods that purport to be eco-friendly are more damaging than glyphosate application."

He comments that there have been few truly scientific trials of alternative weed control methods, and that councils, having signed up to zero carbon, are being pressured into choosing alternatives that generate considerably more carbon than synthetic chemicals.

"The Cardiff study (see below) stands out as the first piece of work carried out in a real life situation and followed through with rigorous data collection."

"GPS on sprayers is so accurate that there is no overlapping during application - we have seen savings of 10% on chemical use."

Nozzle developments have also made an impact, cutting drift and off target application, as well as improving disease control treatment, which in itself improves the sward's resilience and competitiveness.

"Multiple small gains soon become significant," he comments. He believes that increased public scrutiny - anyone with a mobile phone can take HD video - is positive in driving standards upwards.

"Some businesses have not invested in the training and technology to improve practices, but it's now harder to operate in that way."

Cardiff trials treatments

In 2021 Cardiff Council and its weed control contractor trialled three pavement weed control methods across the City of Cardiff to find out how effective and sustainable each method was, as measured against four key criteria: cost, environmental, customer satisfaction and quality. Control methods trialled included glyphosate-based herbicide (applied three times per year), acetic acid-based herbicide (applied four times a year), and hot foam herbicide (applied three times per year). Efficiency and sustainability results showed that glyphosate was the most sustainable, being cost effective, with low environmental impacts and high customer satisfaction and quality. In contrast, acetic acid delivered intermediate costs and environmental impacts with low customer satisfaction and quality, while hot foam generated high costs and environmental impacts but high customer satisfaction and quality.

Based on cost, environmental, customer and quality criteria (efficacy and sustainability criteria) measured, the most effective and sustainable weed control method currently available for pavement weed control in the UK involves the use of glyphosate-based herbicide.

WEEDit - which uses infra-red light to identify weeds for selective spraying - is part of contractor CWC's weed control armoury.

IWM and non-chemical treatments

Kersten has developed its business model around IWM for hard surfaces, offering a range of products aimed at preventing weed development or tackling small weeds before they become deep rooted and more difficult to remove.

"Debris such as leaves or grass clippings builds up and rots down to form soil which provides nutrients for weed seeds. Removing detritus by sweeping it prevents weed growth or where small weeds are present can also remove them," explains sales and marketing director Sean Faulkner.

He points out that different types of weeds grow depending on the depth of soil - where it is shallow, moss or annual weeds and where there is more soil, deeper rooted plants.

"One pass with a brush or application of a heat-based control method can take out shallow weeds, rather than having to tackle deeper roots with repeated passes, so keeping on top of the depth of soil makes treatments more efficient."

The company also offers a range of heat-based treatments, and here also Sean suggests that early treatment is key.

"It's important that operators know how to use these treatments to get the best out of them."

Choosing the right method for the surface in question is also key: "Some areas can be effectively treated by weed brushing, but heat may be a better option on gravel and gives the quickest results when passed over the weed."

Where heat can present a fire risk, hot water or foam may be better, albeit with slower results.

"These methods target the cells used for photosynthesis so the plant dies off, and again work best on young plants without an established root system," he comments.

Sean points out that Kersten petrol-engined weed brushes use around 10 litres of fuel over a period of four hours so are relatively efficient.

"Electric weed brushes are on the way, and we offer battery operated Eco Weedkiller hot water systems which use insulated tanks to keep the preheated water at the required temperature; the water can be heated back at base using green energy such as solar rather than on the go which would need a diesel heater."

Electrical treatment

RootWave Pro is a professional hand weeder designed for parks, gardens and estates. It uses an electrical current from a generator mounted on a truck, ATV or barrow and transmitted via a hand lance to 'boil' the roots of weeds, causing them to die back with zero or minimal regrowth. It comes with a 27m long cable which allows 2000sqm to be treated at a time.

"Treatments are chemical-free and completely targeted, and there is no soil disturbance, avoiding the risk of weed seeds being spread," explains RootWave's Stephen Jelley.

Designed to treat anything from small weeds up to large invasive species, RootWave Pro is suitable for sensitive areas where chemical weed control is not appropriate, such as close to watercourses or favourable plant species. Customers include English Heritage, the Environment Agency and National Parks.

"It has proved to be highly effective against Japanese Knotweed as an alternative to spraying or stem injection and Transport for London are using it at London Underground sites. On small sites, it can remove the plant in one treatment, where roots are especially deep it can take a programme of multiple treatments, but this compares well to the treatment programme needed for chemical control and there is no need to remove debris from the site," says Stephen.

While the initial outlay of around £17,850 means that this is a machine that tends to be purchased by weed control professionals, running costs are low, using around 15 litres of petrol or diesel per day for the generator.

Hot foam

Foamstream uses a combination of near boiling water and biodegradable foam to kill weeds - the foam, formulated from plant oils and sugars, maintains the heat of the water to above 57deg for 15 seconds to improve kill rates and minimise regrowth.

There are two models: the L12 which is powered by a petrol generator and 95kw Honda diesel engine, designed for larger scale operations, and the hybrid M600H, which uses a smaller diesel engine for the boiler and L-ion batteries and is targeted as smaller and inner city applications. They are supplied with 20/30m of hose to the hand lance.

Outputs are up to 700m2 and 420m2 per hour respectively, depending on the density of vegetation.

Designed for use in all weathers, the low pressure application system means that it can be applied on all types of surface, and also reduces splashing and wastage. Results are instantaneous and the heat is also designed to sterilise weed seeds and spores to reduce regrowth.

UK supplier Weedingtech says that for moss and algae, control is achieved in a single annual treatment, and that its multi-purpose properties - Foamstream can also be used for graffiti removal, urban cleaning and to clear chewing gum - give a high return on investment.

With prices at £19,950 for the L12 and £26,100 for the M600H, rental costs for the L12 are from £340-£750, or monthly costs on finance £396 and £518 respectively.

Spot spraying - Infra red

Complete Weed Control introduced the WEEDit selective pavement spraying technology at Saltex in 1997, a development ahead of its time.

Mounted on a quad bike or other carrier vehicle with a spray boom at the front, WEEDit uses an infra-red sensor to locate the weeds as it passes over them by fluorescing the chlorophyll in the leaves, switching on nozzles to apply glyphosate to the weed only.

"Label restrictions that require spot spraying were introduced in 2012," comments Ian Graham of CWC, UK distributor for the Dutch-made system. "The system can now be hired by local authorities, but is used almost entirely through our network as a contracting tool.

We have established a successful contract service and there is now growing interest in using the system."

Ian comments that the technology has developed to offer greater accuracy.

"Hardware and software improvements have allowed the application process to become even more accurate with reduced margins before and after the weed which is being detected."

- Camera guided

Precision application specialist Techneat has developed the WeedWizard, a spot sprayer designed to offer targeted herbicide application on footpaths, roadsides and cycle paths.

It uses camera technology to identify 'green on brown' weed growth on hard surfaces, with artificial intelligence software used to switch on low drift spray nozzles and apply herbicide to the green areas only. The camera, spray tank and 1.2m spray boom are mounted on a quad bike.

"Compared to blanket application just 1-5% of the chemical is used, and the unit can work at up to 5kph," explains managing director Tom Neat. "The low drift nozzles keep the product on target and allow a defined line such as at the edge of a kerb to be sprayed."

There are operational benefits too, he points out: "As the application is automatic, the driver can concentrate on steering the bike and with such small amounts applied, the outfit can cover a lot more ground before needing a refill."

The camera identifies the level of weed pressure and sets the coverage; weeds from 25mm across can be targeted.

"We're using the latest technology to make spraying more accurate and safer, while cutting application costs," explains Tom. The WeedWizard is being demonstrated throughout the country this season before going into production; the price is expected to be £35,000 including a Honda or Kawasaki quad bike.

Tech for turf

John Deere was one of the pioneers of GPS technology for site specific applications in farming, and groundcare has benefited from this.

The Progator GPS sprayer offers 2cm accuracy and individual nozzle control, switching off the spray as the boom approaches the edge of the area to be sprayed according to a pre-set map, and minimises overlaps with Auto Trac steering.

"This offers significant savings in chemical use, which not only benefits the environment, but cuts costs too," comments John Deere's golf and turf specialist Chris Meacock.

For larger turf areas, Auto Trac can also be fitted to a compact tractor and used to steer around straight or curved lines when using a mounted or trailed sprayer, reducing overlaps.

"The financial savings are less dramatic, but this approach can certainly contribute to sustainability," says Chris. "Operations are recorded and mapped for easier record keeping, which makes it possible to prove what has been applied."

Article by Jane Carley.