Polish manufacturer Trigger Composites has begun using drones to survey farmland and provide growers with a photomap that could help increase crop yields and save large amounts of money on fertilizers. 

The drones, or unmanned aerial vehicles (UAVs), use a multispectrum camera to map an area by scanning the plants' leaves and then create a graphic called a Normalized Difference Vegetation Index (NDVI).

Growers can then use this graphic to determine the the state of the plants' health across their land.

Once the grower has that information they will have a good idea of which areas of the farm need specific attention in terms of fertilizer or soil replacement, rather than taking uniform action across the land which could be far more costly than necessary.

While Trigger Composites produces its Pteryx-branded UAVs, it works with associate company Fotomapy which acts as the operator for the technology.

Trigger Composites CEO Tomasz Maik explained to www.freshfruitportal.com while NDVI images were usually captured by cameras on high-tech satellites that would be too heavy and expensive for the drones, the company had been able to use consumer-grade cameras and modify them to achieve similar results.

"What we usually do is use modify the cameras by removing some filters and putting on other ones so they function beyond their original capabilities," he said.

"The main goal is to understand the plants' health. To do this we create a map, but not in the real colors - we have a map in the colors that represent the value of reflective index, and this index tells us how healthy plants are."

When areas are identified in which the plants are not as healthy as other parts, the grower can then go in a take a small number of soil samples to confirm the data provided by the UAV, and from there they can decide what course of action to take for specific areas of the farm.

"When you want to use it for its NDVI value alone it's quite difficult. What we do here in practice is combine NDVI maps and soil sampling," he said.

"Combining those two types of data means you don't have to rely only on the NDVI map, because that will show you which areas are weak, which areas are ok, and which are so-so - so you know what to check.

"The NDVI mapping in my opinion is not the only data you need to make a decision on the fertilizer application."

An example of a Normalized Difference Vegetation Index (NDVI) graphic (Source: Trigger Composites)

Saving 30% on costs

Once the data has been confirmed, the grower will then know which areas of land need more fertilizer than others, or which areas need a complete soil replacement if there is not enough of the organic matter called humus.

The financial savings come as a result of not having to apply fertilizer to areas farmland where it is not needed, and also by only replacing soil where such action is required.

Maik said producers could save 30% on fertilizer costs alone.

"It's very profitable when you compare farms that use all potential of precision agriculture and NDVI maps to a similar farm that applies fertilizer in a traditional way," he said.

"And for the soil, to put compost on 150 hectares costs a lot, but it's not necessarily needed for all the soil. There are usually just a few spots of bad quality because there is no humus," Maik said.

The Trigger Composites head explained that due to the size of the farmland in Europe, growers would most likely hire the services of a precision agriculture company rather than purchasing a drone themselves.

"In Europe you consider a farm to be big if it has about 500 hectares," Maik said.

"In the U.S. it's not a big farm but here it is, and for this kind of farm buying a UAV is not a good option. Not because of the money, but because of the whole knowledge that is connected with the UAV industry, teledetection and so on.

"In Europe it almost always works like there are precision agriculture companies that work for the farms and they help them to improve fertilization application, reduce fertilizing costs, improve the soil, and so on. So the UAV is a product for the precision agriculture industry - not so much for the farmers themselves."

Three times a year

Along with cost savings, the drones also benefit growers by assessing the farmland far more efficiently than could be done using conventional methods, and since they scan the area from the air there is no damage to any of the crops from machines or workers.

In addition, growers would only need to map their farmland using the drone at three important times per year.

"The first is in spring, when the leaves are big enough to be tested by the NDVI map, we can maybe photomap to check the initial fertilizing. If we will see that there are areas which haven't received enough fertilizer we can put a little bit more in those areas to increase yield in the autumn," he said.

"Next, NDVI maps should be made before summer fertilizing, and the last one can be made just before harvest. So it's about three times a year.

"Of course there are some crops that require different things."

While the technology can be used on a wide range of crops, it is best suited to those which have a large amount of green leaves, such as potatoes, corn, and rice.

Photo: Trigger Composites

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