This article has been adapted to common Australian boom widths, tank sizes and speeds, and re-printed with permission from the Nozzle Guy.
You can find the original article here
Increase Sprayer Productivity Without Driving Faster
Timing trumps most things in crop protection. A great spray applied at the wrong time isn’t nearly as valuable as a mediocre spray at the right time. So how do we improve our ability to get things done at the right time?
Often, we try to win races by driving faster. Driving slower can be viewed as a sort of insurance policy: You may not notice the benefits right away, but on days when that extra bit of performance is required, you’re covered.
So how do you get the job done quickly if you can’t drive faster? To answer, we have to look to other opportunities for boosting productivity.
Below are the results from looking at a model to capture all the elements of a normal spray operation that affect timeliness. These were:
- travel speed
- boom width
- tank size
- water volume
- field length
- number of headlands
- turning speed
- fill time
First, we identified a reasonable base condition. For the sprayer, that was a travel speed of 18 kph, a 30m boom, an 5000L tank, a 100L/ha water volume, and a 20 minute fill time. Then, we set up a typical paddock situation, which was spraying a 500 metre run with two sprayed headlands and a turning speed of 10 kph. Finally, we changed one factor at a time to determine its relative importance.
Before we discuss the results, let’s make it clear that just because changing some of these factors improves productivity doesn’t mean we’re recommending them! For example, adequate water volume remains an important input that improves coverage and permits the use of low-drift sprays. Larger tanks increase compaction and take more power, and so forth.
Here’s what we found:
For the base condition, the sprayer spent 34% of its driving time turning, and 19% of its on-field time stationary (i.e. filling). For every hour spent on the field, just over half the time (54%) was spent spraying. This resulted in an average productivity of 29 ha/hr.
Increasing the spray speed to 25 kph increased average productivity to 34 ha/hr, but it also increased the proportion of time spent turning and loading, resulting in just 45% of the field time spent spraying.
Decreasing the loading time from 20 to 10 minutes reduced the proportion of field time spent stationary to 11%, covering 32 ha/hr at 18 kph. Surprisingly, this was the productivity-winner, resulting in 59% of on-field time spraying.
We discovered other powerful productivity factors, and chief among them was boom width. A 33% increase in boom width from 30m to 36m gave a productivity boost to 31 ha/hr, close to the same result as increasing the travel speed to 25 kph earlier. Similar side effects occurred: more time turning, and a greater proportion of time filling, as we saw with faster travel speeds.
Two other factors that had similar effects to fill time were water volume and tank size. Less water and larger tanks increased productivity by decreasing the fill frequency, with effects similar in magnitude to speeding up the fill time. Decreasing the water volume from 100 to 50 L/ha increased productivity to 32 ha/hr by decreasing the proportion of time the sprayer was stopped from 19% to 11%. Increasing from an 5000 to a 8000 litre tank increased productivity to 33 ha/hr, again by decreasing the proportion of time spent filling to 7%.
Taken together, a sprayer with a 36m boom, a 8000L tank, applying 100L/ha and filling in 10 min had an average productivity of 36ha/hr. And this was achieved without driving faster than 18 kph. If you can drive a whole kilometre before turning, that number rises to 46 ha/hr, a surprisingly large 10 hectares/hr gain.
The perspective of minimising downtime extends to other tasks, too:
- Be more prepared for the job by reviewing the product label in advance, noting the correct mixing order.
- Keep extra nozzles, clamps, and nozzle bodies in the cab.
- Don’t clean plugged nozzles, replace them.
- Use low-drift nozzles so a small increase in wind doesn’t shut you down.
- Ensure all the products needed are on the tender truck (e.g. pesticide, adjuvant, tank cleaner, anti-foamer, etc.).
- Consider switching to 3” plumbing (pump rates of 1350 – 1800 L/min are possible).
- Make sure your inductor won’t be the limiting factor. For example, product pumps can be awfully slow when the product is cold. It might be worthwhile to explore a venturi system.
Speeding up the fill process is a good idea, but be careful with certain products. Dry materials such as the propyzamide and diuron require time to hydrate in water so they mix properly. Some operators pre-hydrate these in a smaller tank, while others get an extra tank to pre-mix whole loads and simply transfer them over.
Also think about the time spent cleaning the sprayer. Thoroughness is important, but perhaps there are efficiencies to be gained there as well, like never letting a sprayer sit after spraying. We’ve written about continuous rinsing, for example, to improve cleaning speed and effectiveness.
So, the quicker we can spray, while ensuring a quality job, the more effective our crop protection practices will be. We encourage you to use our Productivity Calculator to determine your best configuration.
Got a productivity tips to share? Let us know! And remember: In spraying, the race is won in the pits.
|Factor||Base||Drive Faster||Fill Faster||Spray Wider||Less Water||Bigger Tank||New Sprayer|
|Travel Speed||18 kph||25 kph||18 kph||18 kph||18 kph||18 kph||18 kph|
|Fill time||20 min||20 min||10 min||20 min||20 min||20 min||10 min|