'A bird’s eye view of what is happening' - drone potential for maize crop agronomy
Precision technology is becoming the buzz word of the moment in agriculture and is showing no let-up as increasingly high-tech equipment makes it way to the fore.
Hannah Park
Among the offerings are drones, technology which independent agronomist Craig Green has been examining the potential value of around maize and other arable crop agronomy in recent years.
Speaking at the Maize Growers conference earlier this month, Mr Green highlighted how their popularity has continued to rise for business and recreational use.
He outlined how public sectors industries like the fire service, healthcare, police and military are using drones to evolve their services as well as business like amazon prime which is trialling the use of drones to deliver small packages in the USA.
In agriculture, he explained how the potential for drones was increasing as they were increasingly being used for jobs like spraying on heathlands where boom sprayers can struggle to get to as well as for bracken control across large areas.
As part of his work, Mr Green undertook his own trial to see whether maize agronomy could be done by a drone in place of an agronomist.
The theory was tested by him (the agronomist) walking the field and making recommendations as he normally would and a BASIS certified farmer interpreting the information provided by the drone which Mr Green, a SUA certified drone pilot, flew.
The trial was undertaken on a 10-hectare (25-acre), south facing ex-potato field with a medium soil type (P=3 and K=2) which was in a long-term arable rotation.
The crop was precision drilled with 40kg of N on the seedbed. DAP was applied at drilling, with additional N planned at this point for third leaf emergence – before the drought of summer 2018.
Drone images were taken pre-crop, at drilling, emergence of leaf one and four and at closing canopy using a standard DJI Phantom 4 model, with rented mapping software from Agrovista UK used to produce the analysis map.
He said: “A drone image will take out green pixels, so the more depth of green visible on an image, the healthier the plant.”
“Images at third leaf showed poor plant emergence in parts of the field, most notably in the south-west and north of the field, as well as some in the south-west, with rabbit damage becoming clear at fourth leaf.
At canopy closure, this became less apparent, although coverage of plants in the centre of the field was thinner.
“Weeds were identifiable in the drone images before the maize and in the maize, but only once they were as big as a 50p piece in size and interestingly, my recommendations (the agronomist) and the qualified farmer’s (drone interpreter) for herbicide and fertiliser application were the same.”
Explaining whether he thought maize agronomy could be done solely with a drone, Mr Green said drones would be better used as an assistant to, rather than a replacement for, agronomists on the ground.
“Drones are a reactive, rather than a proactive tool, but can be useful for spotting wider problems an agronomist may not be able to see as clearly.
“When scenarios show up on a drone image they have already happened. But with that information is the opportunity to make better decisions, potentially around seedbed conditions, weed control or nutrients.”
“They give a bird’s eye view of what is happening on the ground which means they can be a good checking tool for weed patches, maize eyespot, compaction, land drains and diseases, as well as being used to make biomass predictions.”
As part of his trial, Mr Green explained the drone image was able to pick up delayed emergence in the centre of the field because of a paler first leaf at emergence one, which never caught up as the crop progressed.
This may not have been noticed by an agronomist on the ground walking the field on an average two-week basis.
“Using a drone is a quick process. I can check 140 hectares in 20 minutes using two batteries and I know the whole field, including corners, has been checked.
“But flight time is a drawback (on average 20 minutes per battery), weed ID is more time consuming and specialist software is needed to produce the images for analysis, as well as weather conditions which can dictate when to fly.”
Unlicensed pilots: What are the rules when using drones
- Drone must weigh under 20kg
- Fly below 120m (400ft)
- Always be in a direct line of sight within 500m, but with a CAA licence this can be increased slightly
- All GPS controlled, so will return ‘home’ if there is a problem or low on battery
- Do not fly within 50m of a person not under the operators control or within 150m of a built up area
- Images captured must not break privacy law and with a CAA licence data can be used commercially
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