Crop protection - Ways to reduce waste in pesticide and fertiliser applications

Manufacturers are developing new technologies to help growers reduce waste in pesticide and fertiliser applications, finds Richard Crowhurst.

Agrifac's Condor sprays from 50cm to 325cm in height - image: Agrifac
Agrifac's Condor sprays from 50cm to 325cm in height - image: Agrifac

The use of technology by growers in application equipment for pesticides and fertilisers continues to increase, and not just the use of tools to improve precision.

Irrespective of the size of the job, reducing wastage during application is vital for environmental and commercial reasons. "The greatest changes in application machinery are the use of electronics to aid calibration, work rates, accuracy and to save inputs by only applying the rate the crop needs, known as variable rate application," explains Amazone brand manager Simon Brown. "The biggest driver to the use of electronics is the cost-saving potential from automation - and this is applicable to both fertiliser spreaders and sprayers."

The use of GPS technology for precision application has increased significantly over the past three years. "About 70 per cent of our sprayers now have auto-section control to reduce overlapping and crop damage," says Norfolk-based Sands Agricultural Machinery sales manager Ian Griffin. "We have a 30 sections fitted with such a system."

Non-GPS developments

Another popular tool on today's sprayers is automatic boom-height control. "Auto boom-levelling is on the up and its reliability and effectiveness now makes it worth considering," says Griffin. "Speed is the restricting factor as to how well it works. For the vegetable grower travelling at forward speeds around 12 kmph it works extremely well, but at speeds around 16 kmph its efficiency is greatly reduced."

Amazone offers automatic boom-height control systems capable of running at forward speeds up to 20kmph. "The system reduces drift by keeping the boom at the target ride height because the temptation is always to err on the cautious side," explains Brown. "We know that adding 20cm to the normal boom height doubles the drift. The beauty of automatic boom-height is a reduction in driver fatigue, giving the ability to run for longer days with no loss in application accuracy or increased danger to the environment."

Agrifac's new Condor self-propelled machine is a field-scale sprayer but, according to sales and marketing manager James Lane: "It has features and options that provide it with the means to work in specialist crops. In terms of height control, we offer spraying heights now from 50cm to 325cm, with track widths possible from 150cm to 300cm, depending on model, but all on the move."

"Boom-levelling will become more popular as customers start to see its advantages," agrees Griffin, adding that another factor in its uptake is the recommendation of some crop protection companies to increase spray heights to as much as 50cm above the canopy to improve coverage.

Other developments include LED lighting to monitor nozzle performance and automatic steering systems.

Air assistance

Improved coverage can also be obtained with the use of air systems. Agrifac's Condor sprayer can be fitted with AirFlowPlus. "AirFlowPlus is our take on the air boom system," says Lane. "It is employed by growers to force air under a crop canopy to improve penetration. Our system can be angled to suit wind conditions and crop position."

"We have noticed a swing back towards air-assisted spraying in the form of air bags," comments Griffin. "This can achieve better penetration in dense crops such as carrots and Brussels sprouts and also helps with drift reduction. These systems can cost up to £10,000 more than a standard spray boom, but some customers feel this is worth it."

Discovering new methods

With the loss of crop protection chemicals, particularly herbicides, new application methods have had to be developed. Micron Group has recently launched an improved Varidome band sprayer featuring an electronic controller. This shielded, low-volume inter-row sprayer uses controlled droplet application to safely treat weeds growing between rows and wheeling areas. "Possible applications include weed control in carrots, onions, leeks, parsnips, oilseed rape and maize, well as ornamental plants and tree nurseries," says group marketing manager Ausra Landey. "The Varidome is equipped with shielded rotary atomisers that produce optimum-sized spray droplets for maximum spraying efficiency and features adjustable spray heads with separate width settings for crop rows and wheeling areas."

The company will be launching a three-bed Varidome unit at LAMMA 2012. "This machine will treat a total width of up to 6m, which will significantly increase productivity," adds Landey.

Micron also produces specialist orchard and bush-fruit sprayers, such as the Flexidome, a shielded tractor-mounted sprayer for weed control in soft fruit grown in raised beds outdoors or in Spanish tunnels. It also offers the Enviromist range, which is ideal for weed control in cider apple orchards, vineyards and bush crops such as blueberries and blackcurrants.

Specialist equipment can also be found in row crops, particularly potatoes, where Chafer Horstine is well known for its range of precision insecticide and fertiliser applicators. The company has recently introduced electronic drive control in the form of its Wizard Controller, which is more accurate than the traditional land-wheel design. According to the company's commercial manager Rob Starkey: "Automated calibration eliminates the need to alter sprocket ratios and positive metering shut-off ensures chemical is not left on the soil surface."

It is not just crop protection products that are benefiting from these developments - they can also be used to improve fertiliser application. "We have recently developed an easy-fit kit to enable oil-seed rape farmers with 'one-pass systems' to apply computer-controlled liquid fertiliser with high levels of accuracy directly into the ground as it is worked and air seeded," says Patrick Dixon of Cleveland Sprayers.

"We supply a stainless steel pencil jet designed to apply fertiliser in a tight band, which gives no drift. We have been asked to adapt one of these units for cultivators working in crops of sprouts and we see no reason why we cannot use the same technology with a little adaptation to fit the weeder/cultivator."

Post-application technology

"Wash-out systems have reduced environmental risks and operator contamination, with in-cab systems offering automated sequences and stage-by-stage dilution to avoid cross-contamination," says Brown. "We have just launched the first external boom wash-off system for automatic in-field cleaning of the outside of the sprayer boom."

Agrifac also has a pump system that is capable of completely emptying the tank. "By enabling a complete spray out, the chance of contamination by accidental discharge of residues is also reduced," says Lane. "It also ensures that different crops do not receive a dose of another chemical. This complete clean out is vital for farmers such as those producing field scale salads and vegetables for supermarkets, where compliance is a key to retaining contracts and securing prices for their products."

Glimpse of the future

We asked manufacturers to look into their crystal balls and predict what new developments growers would be specifying in the next few years. All agreed that GPS technology would become standard, with height control and auto steer becoming much more common.

"Electrically driven machinery will become more popular as manufacturers try to reduce emissions. Generating electricity with the tractor engine is easier than converting that to PTO or hydraulic power," says Amazone's Simon Brown, revealing that the firm, which already has an electrically driven trailed sprayer, will debut a similar maize drill at Agritechnica this month.

Headland control systems, which currently concentrate on avoiding overspray and drift, are likely to become more complicated, with one manufacturer working on a system to compensate for cross-winds on its fertiliser spreaders.

There will also be more control of filling technology, with machinery manufacturers and crop protection companies working together on a system for pre-mixing chemicals outside the main spray tank and then injecting the mix directly into the spray line with the fresh water. To prevent the need for washing out, new control programmes that monitor chemical use and adjust application rates to result in empty tanks are also being developed.

Regulation inspiring future developments

"Regulation will be a big driver for change over the next three years," says Ausra Landey of Micron Group. "Manufacturers will have to ensure their products comply with the revised machinery directive, particularly with regards to environmental requirements and cleaning of sprayers."

She adds that manufacturers will have to adapt their application machinery to comply with the sustainable use directive and further requirements for integrated pest management, many of which are yet to be defined.

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