Sprayer safety

Safe crop protection is what HARDI specializes in. Professional use of crop protection products today implies focus on:

  • Maximum biological effect and levels of control 
  • Minimum residue levels in food products 
  • Minimum risk of environmental contamination from drift and run-off
  • Maximum consideration for capacity, ease of use, safety and precision.
Filling the sprayer

Reduce risks when adding plant protection products

  • Add plant protection products to the sprayer in the field so that you:
    - avoid using the same spot every time you handle concentrated chemicals
    - benefit from an active soil breakdown of minor spills
    - avoid any risks from transporting a full tank of spray solution
  • Carry the plant protection products in safe lockers on the sprayer. It must be possible to catch any spills from the containers.

Water filling

When filling the sprayer with water, avoid any risk of over flow or return to the water source. Make certain that no spillage could end up in drains, wells, ditches or surface water unless the filling takes place on a special concrete area with efficient drainage to a safe container.

In practice, it is safest to fill the sprayer from a separate water tank. If you must fill directly from a shared water supply make sure the end of the filling hose is kept at least 10 cm above the sprayer filling hole.

The sprayer must not be left unattended while filling.

Sprayer filling must not take place anywhere near wells or drills – please check your local regulations.

To minimise the impact of small spillages or dripping, water filling should preferably take place in the field. Otherwise, an area covered with grass is better than stones or gravel. The safest alternative is to carry out the filling under a roof and with drainage to a separate tank.

Agrochemical filling
Adding the plant protection products should also be done at varied places in the field.

Otherwise, filling should be done on a concrete area where any spills can be picked up using special absorbent granules. If this is not possible then fill over a dedicated grass area that can help contain and degrade spilled chemical.

Transporting concentrated chemicals between the farm buildings and fields must be done safely and in compliance with local rules.

Generally, products should be carried in a locked box where any spills will be contained. Carrying a shovel and plastic sack is a wise precaution, as they can be used to pick up any concentrated chemical that gets spilled or dropped.

The sprayer pump should be left off while transporting the sprayer from farm to field – to ensure the system is not under pressure.

Empty agrochemical containers must be rinsed with either the rinsing nozzle in the chemical filler or with three lots of clean water. In both cases it is important to move the container to make sure the rinsing is fully efficient.

If using a rinsing nozzle, the time must be adjusted to suit the container size and a final rinse with clean water will ensure the container is as clean as can be. The rinsing water must be added to the main spray solution.

Rinsed containers need to be stored securely until they can be disposed of properly.

Cleaning inside the sprayer

Label guidance
If a specific cleaning method is given on the label then this must be followed. What follows is for general guidance only.

Always remember to wear gloves, face shield and plastic apron/appropriate waterproofs when cleaning.

Residual volumes within the sprayer
Sprayer cleaning begins with accurate calibration: when flow rates are as expected there should be very little spray solution left in the tank at the end of the job.

Encourage in-field cleaning
The emphasis today is on in-field cleaning using dedicated equipment on the sprayer. A dedicated rinse tank mounted on the sprayer is the key quick and easy field cleaning.

Dilute any small amounts of liquid left in the tank with clean water, then spray it out in a way that complies with its approved use and avoids over-dosing plants. Diluted 10 times and sprayed over the just-treated area will often meet that requirement simply and effectively.

Otherwise, larger residual volumes can be drained and disposed of by an authorised company.

Infield rinsing with rinsing tank ( a daily routine)
The most efficient use of water in the rinse tank is achieved if the water is used in 2 to 4 lots; using half, one third or one fourth of the water for each rinsing. It is important that all valves are operated whilst rinsing so that trapped spray solution is removed from everywhere in the system.

If the sprayer is equipped with a rinsing nozzle this should be activated during each rinsing to achieve the most efficient cleaning of the internal spray tank. It is important that the sprayer is emptied as much as possible after each rinsing to ensure maximum dilution with each new introduction of rinsing water. Spray the rinse water out over an area of the crop just treated, ensuring the maximum dose for the product won't be exceeded.

Rinsing without rinsing tank (daily !)
To minimise the amount of rinsing water being used and disposed of, the tank should be flushed internally using the equivalent of 10% of the tank volume. This is repeated twice.

A high pressure cleaner is also useful. After each rinsing, the rinse water should be sprayed out over the just-treated crop, a similar area, or an area of low-valued vegetation. Before applying the rinsing water over the crop, all valves must be activated for a complete rinse.

However you dispose of the rinse water, it must comply with your local rules and regulations. In particular, make sure no rinse water could end up in ditches, drains or waterways.

When switching from one product to another, it may be necessary to chemically break down the smallest traces of active chemical that are stuck to the structures of the sprayer. Follow any recommended procedures detailed in the agrochemical label or documentation.

Otherwise there are 2 possibilities:
Cleaning without rinsing nozzle: Fill the spray tank with water and an approved cleaning agent like ammonia, bleach or a product marketed for sprayer cleaning. Turn on the pump and let the solution circulate through the whole system for 15 minutes.

Be sure to operate all the valves – on sprayers with a self-cleaning filter, increase pressure until the safety valve is activated, then reduce the pressure again. To ensure that the tubes and hoses on the boom are also cleaned remember to let the nozzles spray onto low-value grass for a while. Leave the sprayer for a couple of hours to ensure that any chemical residues of chemicals are deactivated, then spray the cleaning solution onto a dedicated grassed area.

Dismantle and remove all filters and nozzles and place them in a container of the same cleaning solution as used in the spray tank to soak. Then give them a final clean with a brush, before rinsing them in clean water and fitting them back on the sprayer. Finally, rinse the entire sprayer (inside and out) with clean water, and spray this rinse water onto an area of low-value grass.

Cleaning with a rinsing nozzle: Fill the tank to 1/10 of the capacity with water and cleaning agent. Activate the rinsing nozzle and let the liquid circulate in the whole liquid system for 15 minutes whilst operating all handles and valves. Then follow the same procedure described above for emptying the tank and cleaning the nozzles, etc.

Protecting the environment when spraying

A wind streamer mounted in front of the tractor will increase your awareness of the wind direction and its likely force. It will help you to know when to be extra cautious and maybe react with coarser nozzles.

Plan ahead and try to anticipate problems. If the wind speed is currently acceptable but is forecast to rise, for example, consider spraying the downwind swath edges first.

Never try and do maintenance with spray liquid in the tank or in the field.

Escaped spray liquid will soon apply a huge excessive dose that can run-off and contaminate water within the soil or adjacent to it – or cause a sterile area of soil to be formed that will remain for many years.

Avoid over spraying as it is wasteful and puts your crops at risk. Use the boom section valves for areas which are less wide than the swath. If treating an “angled” field it is worth the effort to turn on off the boom sections as the boom passes over the already sprayed ares.

HARDI TRIPLET nozzle bodies have an ‘off’ position for you to use if you need to control swath widths by 0.5 m sections.

External cleaning

An area covered with low value, unused grass may be an appropriate “filter” for distribution of rinsing water from the sprayer and an appropriate place to clean the outside of the sprayer and tractor. The grass hinders movement of the agrochemical solution and encourages it to become chemically bonded to soil particles while it degrades.

It is advisable to dedicate such an area - moved every year - on the farm.

Another possibility
Another option is to have special equipment fitted for external cleaning of the sprayer in the field. Clean water from the rinse tank has to be reserved for this purpose.

Hoses with a high pressure supply are being used to rinse those areas of the machine that get the greatest level of contamination; the rear of the tank, the booms and wheels.

The frequency of external cleaning will depend on spray quality and wind direction, as well as exposure time and temperature. Evidence suggests that infield cleaning should be done at the end of every spraying day for both personal and environmental safety.