Every summer our company faces an important challenge: making multispectral maps of dozens of fields with soybean and corn crops in critical periods. All the precision work of an agronomic services company depends on achieving it on time and with the highest quality.
By Pablo Sandoval – Operations Manager 21SUR Aerospace
During the last years, the austral summers have challenged us to plan the mapping of large extensions of territories in Uruguay. With agriculture playing a critical role in our economy, farmers have had to rapidly adopt new technologies to keep up with the world's growing demand for food and commodities. This factor has made the term "precision agriculture" a common word among them.
In Uruguay, aerial mapping with drones was successfully implemented as of 2010 by private companies and the support of academic researchers. The bases for the intelligent management of crops from an aerial perspective were introduced that year by the ADP company, setting a precedent that would later be followed by the other companies that bet on airborne remote sensors.
At the governmental level, the Uruguayan Aeronautical Authority (DINACIA) had to promptly implement the regulations in accordance with these activities. Since then, this institution in charge of national aviation security has had to regulate this activity, quickly adapting to the new technologies that were already beginning to break through forcefully throughout the world..
21SUR Aerospace is specialized in remote sensing analysis and aerial mapping for the agricultural and forestry sectors. We carried out the first commercial BVLOS operations in Uruguay and achieved the first "swarm" operation with our eBee (SenseFly) UAVs.
From the beginning it became clear that due to the large amount of agricultural area to be surveyed, a type of drone was necessary that could remain in the air for as long as possible, therefore the indicated choice fell on fixed-wing UAVs, being ruled out multirotor drones for this task.
Since the beginning of 21SUR's operations, an important alliance has been made with Pronutrition Agro Technologies. This company is specialized in precision agriculture, providing direct recommendations to its clients, relying heavily on state-of-the-art technology. Our association with this company has been vital in providing useful tools for farmers.
Our role during this aerial mapping season, as well as in previous mapping seasons, has been to provide Pronutrition with vital input in their decision making: reflectance maps, index maps (NDVI, EVI, etc), differential irrigation analysis and dry land The aerial surveys that began with the corn crops in December have continued with the mapping of soybeans in the months of January and February.
21SUR Aerospace has carried out aerial surveys with multispectral sensors in soybeans and corn with an average of 8,000 hectares per year, although in certain seasons it has been necessary to survey peaks of between 12,000 and 13,000 hectares scattered in different areas of the national territory.
The time we have to provide our clients with the processed information is limited, since it is necessary to map the fields in the early reproductive stages of the crop (r.1 or r.2 in soybeans) for this information to be useful. As a company, we must take into account that most crops reach their critical stage practically at the same time, so we must survey the entire extension in the shortest possible time.
To achieve this we have had to develop our own mapping techniques. Our need to meet the great demand prompted us to adopt a highly efficient work strategy to meet the times set by our clients.
The human eye can only see a crop in a limited width of the spectrum (red-green-blue), while multispectral sensors allow us to expand to infrared bands (NIR) and red edge (RE), bands well defined that show the different situations of vigor of the crop. The most used indices are NDVI, GNDVI and EVI.
The purpose of the data obtained with aerial photogrammetry is to create leaf sampling maps. It consists of areas where the deficiencies are shown on maps with color differences of a pre-established scale.
Once 21SUR Aerospace processes the cartographic information obtained with the drones, it is loaded into a mobile browser. This information is then used by Pronutrition's field sampling operator, who extracts and subsequently sends the samples obtained for analysis. The analyzes are processed in the laboratory and the subsequent recommendations are made to the farmer by his agronomic team. This process is completed in a few days, thanks to the agility and versatility that these tools provide.
The result is to have very precise information and in record time on the status of the different areas of a crop, allowing specific problems to be corrected or carried out in a different way; This results in greater savings for the producer and in turn increases the potential of his crop by acting intelligently at the right time.
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