"Fertiliser costs a fortune," he said. "It's all about efficiency and getting the biggest bang for your buck."
This opportunity to target specific patches of land with drones is something that Ireland's official research agencies are taking very seriously.
"We're doing some tests with drones to look at what they can offer in terms of crop yields," said Richie Hackett, a crop researcher for Teagasc who is looking into the flying machines' potential for agri-business.
"It's normal that one part of a field might yield more than another. So using drones to collect data and map from above can tell you exactly where you might have a problem with one part of a field. You can then optimise your use of fertiliser, or herbicide or whatever, in a better way."
Mr Hackett said that he expects drone technology to continue progressing "in leaps and bounds".
"There could be significant environmental benefits as much as anything else," he said.
While using drones to pinpoint patches of land in this way could prove helpful to some farmers, others may soon turn to drones to spray crops or control weeds in their entirety.
DJI, the biggest manufacturer of popular and consumer drones, has just launched a new drone model specifically for spraying crops and land.
Its MG-1 model can cover between seven to ten acres per hour and is, DJI claims, at least 40 times faster than manual spraying systems. It can carry up to 10kg of liquid, including fertiliser or pesticide.
"The intelligent spraying system automatically adjusts its spray according to the flying speed so that an even spray is always applied," said a spokesman for DJI.
"This way, the amount of pesticide or fertiliser is precisely regulated to avoid pollution and economise operations."
It only has 12 minutes of flying time per battery recharge, although spare batteries can simply be swapped in on site. But with GPS and computer memory built in, the semi-intelligent machine not only comes back to base as soon as it is low on battery life or suffers an empty liquid container, but it remembers exactly where it left off with the spraying.
"As soon as you place another battery inside, it goes right back to where it left off to finish the job.
It also has an advanced radar feature that lets it scan and remember the terrain below it as it sprays. This means that once you set the height from which you want it to spray, it will keep that exact distance from the ground, adjusting itself as it flies.
However, most Irish farms are not yet at the point of considering drones at such an industrial scale. Anyone considering one in the short-term may prefer simply to use the camera on board for tagging identification purposes.
That's what one timber company in Galway is doing.
"We use a drone primarily for counting stock," said Mark Dunne of the Murray Timber Group. "Timber stock is very large and the sites tend to be very large. The easiest way to count it is to put the drone up. There's a significant cost saving involved."
Other uses for drones include keeping track of different livestock herds and streams.
"Increasingly, all animals have to be tagged," said Paul Brennan. "A drone can fly down a field to check that everything's in order."
The use of drones in Ireland is rapidly increasing, with several thousand now in operation across the country. However, Ireland is at an early stage in deploying drones as a standard farming technique, said Teagasc's Richie Hackett.
"Potential is the best word for it right now," he said.
Costs vary from €1,000 to €8,000
There are a growing number of drones that can either be adapted for agricultural use or are specifically designed for farm-based work.
For basic aerial reconnaissance, such as counting bales or keeping track of livestock, 'prosumer' models such as DJI's Phantom 4 (€1,600) work fine. The Phantom 4, which has has been reviewed on Independent.ie, flies for just under 30 minutes on a single charge and has an 'ultra high definition' video camera that allows the user to pick out minute details on screen when played back. Like many other drones, it is flown through a dedicated controller and the user's smartphone or tablet.
Cheaper versions, such as the Phantom 3, are also straightforward to use and cost under €1,000. However, such drones generally cannot fly in rain.
Bigger, custom-made agricultural drones can fly in rain but cost from around €8,000 upwards. These include models from HSE and DJI, as well as a number of Chinese brands.
The rules of the sky apply
There are certain rules you need to obey if you want to operate a drone over 1kg in weight (which is almost any model suitable for farm use) in Ireland.
First, you must register the drone for free on the Irish Aviation Authority's website (iaa.ie). Even then, there are a few basic rules you have to adhere to when flying it. According to the IAA, it can't go over 120m (around 400 feet) in height, nor can it be flown over 300m away from you.
Urban or built-up areas are a general no-no and you also have to make sure that it doesn't come within 120m of any other house, farm building or person not affiliated to you or without their permission.
In general, you can't fly a drone over an "assembly" of people and there are strict rules against flying it in "controlled" airspace, particularly around aerodromes, airports and military installations.
Lastly, and this is a tricky one, the IAA says that you need a special license -- on top of your registration -- if you want to use the drone "commercially". Requiring verified training and a higher cost, this is primarily aimed at commercial videographers and camera operators but probably equally applies to regular commercial farm use, whatever that may be.