Reducing aerial spray costs

Why do aircrafts cost so much?

Agricultural aircraft these days are high tech pieces of equipment. They have advanced far since the early days of Tiger Moths and scarves flapping out the window. The turbine powered aircraft of  today are productive and efficient and everything is computerised. They cost a lot of money but can cover a lot of area in a small time. The trick is to be able to manage it so that a lot of area is covered and not a lot of time is taken.

An aircraft costs are broken into two areas:

  • Fixed Costs. These are the costs that are incurred each year regardless of the amount of work that is done. This includes insurance, interest payments, pilots salary and some maintenance. This means an aircraft must do a lot of work each year to dilute these costs over each hectare. An example is insurance which currently costs about $1000 per week regardless whether we work it or not. If we do 1000 hectares per week that is $1 per hectare. If we do 4000 hectares that is $0.25c

  • Variable Costs. These are the costs per hour to operate the aircraft. If the aircraft is sitting still these costs are not incurred. Examples are fuel and  maintenance. These costs are pretty high and run between $10 and $15 per minute. This means that when an aircraft is running it needs to be covering as many hectares per hour as possible.

So an aircraft costs lots to just sit there and then lots more when it is going. Air Ag management strategy is all geared to making sure that the aircraft covers a lot of hectares each year and that it uses the least number of hours to do it. Of course in the agricultural world this never happens and we end up having too much work to do in the wet seasons and nothing to do when it is dry.

The other issue is that it is the aircraft user (ie you) who mainly determines how many hectares the plane does each year and how long it takes to do it. This article is aimed at ensuring you are aware of what you can do to reduce your aerial application costs.

Hourly Rate

An aircraft does about 220kph with a swath width of 20m. This equates to a spraying rate of 7 Hectares per minute. Pretty impressive!  If we like to return about $23 per minute to make any money that equates to $3.30 per hectare we need to charge!. However in the real world our long term average is about 1.8 Hectares per minute and we need to charge about $13 on the average. So what is going on?

The trouble is the aircraft does not spend all it’s time spraying. It must travel to the field, fly around and check things out, work out the map, spray a run, do a turn at the end of the field, return to the strip for another load etc. In reality only 25% of the time is spent productively spraying.

 The picture shows in yellow the wasted travel on a relatively easy to spray field. Imagine if the field had funny bits jutting out or followed around a creek line.

Ferry to the job

This is wasted time and increases as the job gets bigger due to more than one load being required. If you are more than 10km from an airstrip it is costing you too much money. Building an airstrip on the farm is the answer and one of the major inputs you can have into reducing spraying costs. People who do not spray very often or have small holdings should consider chipping in with a group of neighbours and building a strip for everyone to use. Check out our web page where we go into this in more detail.

The length and size of the fields

Each spray run requires a turn at the end that takes about 30 to 40 seconds. Fields that have a longer spray run need less turns. That is more time is spent spraying before a turn is needed. It is difficult to manage around this one as your fields are fixed,  however these points should be considered when at the crop planting stage.

  • Try and plan your fields so that they are in longer rectangular areas than squares or triangles. Some people farm within fence lines that were put there 100 years ago. Maybe crops should be planted in big strips from boundary to boundary. There are obviously other factors such as soil type and other farming activities to consider , but sometimes some lateral thinking doesn’t hurt.

  • When you do a spray job, consider doing all the area at once rather than doing a bit today and a bit next week. Bigger areas make for cheaper jobs.

  • Try and do all the area with one product rather than different products or rates in each field. Obviously there are times when this will not be possible, but is a 100ml different rate of Roundup really going to make a difference between those two fields?

The amount of water you apply

The more water per hectare you apply, the more trips back to the airstrip and the more expense. Read on our web site how to determine correct water rates to use. More is not always better. The product label will also dictate a minimum water volume to use. If you must use high water volumes, you can negate this cost by using an airstrip close to the job to cut down on the ferry costs.

The swath width

If the swath width is narrower the more turns are necessary and costs go up. There is not much you can do with this one as we determine the swath width to ensure a good quality job. There is also information elsewhere on the website about how we do this. Swath width effect is reduced in longer larger fields where the spray time/ turn time ratio is higher and has less effect on the costs.

Management

Being organised is a good way to ensure that while the aircraft is working for you it is productive and not being stuffed around. When you have a piece of gear on the farm costing you $23 per minute you should make sure you have all your ducks in a row. Do your spray management planning and ensure that you have notified neighbours and know what susceptible crops are around etc. This way we can get straight to work rather than having to circle around inspecting crops etc.

Having an aircraft regularly come to your farm means that the pilot becomes familiar with your fields. Once a field has been done a couple of times we work out faster ways of doing it, we do not need to spend time circling working how to decipher the map etc. You also get experience using the aircraft and get to know how to operate it best.

Summary

The main things you can do to reduce the cost per hectare are:

  • Get a strip close to the farm.

  • Give the good long fields to the aircraft, consider doing difficult areas around the creek with the ground rig.

  • Plan ahead and ensure everything is organised.

  • Use us regularly so we both get to know each other.

Air Ag are always happy to give a quote on any job. If you provide a map with the fields marked we can easily calculate costs and help you decide what spraying options you should choose. We may be able to suggest improvements in how it is done. We like talking about our job and are happy to give advice.

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