Today, the agricultural sector is increasingly able to take advantage of the opportunities offered by drones. There are two main lines of use in agriculture.
One and more common is data collection, also known as monitoring. The monitoring drone is a UAV suitable for remote sensing. When remotely sensed, electromagnetic radiation from an observed object (in this case, the culture in the field) transmits information to the sensors on our drone. We know that electromagnetic radiation spans a very wide wavelength spectrum, but now in agriculture we mainly use the visible light and near infrared (NIR) range. With the continuous monitoring of the area, we have the opportunity to assess the early weed and water management problems in a given culture, to determine plant stress, eg water shortage, nutrient shortage, crop estimation, to apply decision-making operations supporting game damage estimation.
Frequent flights provide up-to-date information about the area, so that changes in the state of each phenology can be detected quickly and efficiently in a cost-effective way. In addition to quantitative parameters, we can also detect qualitative characteristics (eg vegetation mass, shadow and wind effect, etc.) for which we use different indices. The best known of these is the normalized vegetation index NDVI. The point of using the index is that the leaves of our plants reflect light differently when they are healthy and well-nourished or not. Based on the algorithm, we can identify the problem before we can detect it with the naked eye.
The other area of application will be spraying. The use of spray drones will be more and more widespread nowadays, as it can be used more cost-effectively to apply nutrients or even irrigate plants. Given today’s weather, it is extremely difficult to find a period when the farmer can intervene at the right time. With the help of spray drones we can perform effective treatments regardless of the soil condition and the height of the plant. The question rightly arises, how is it possible to carry out efficient spraying with these devices so that the tank of the largest drones is only 20 liters? As a farmer, we are used to applying an average of 200-300 liters / ha of spray liquid per hectare, this number can be up to 1000 liters in an orchard.
Thanks to these developments, the possibility of using controlled droplet spraying “CDA” technology on a spray drone is under development. The feature of the technology, in contrast to traditional spray systems, is that it does not “press” the spray liquid through a nozzle of a given diameter using high pressure, where the spray droplets are torn indefinitely and droplets of up to 50-300 microns can be formed. Some of these evaporate or converge and drip along the leaf vein, resulting in a significant decrease in efficiency. CDA technology is used to apply spray liquid to other, in this case mechanically dripped, rotary disk nozzles using gravity, these nozzles can produce any droplet size in the range of 5,000 to 15,000 rpm, in almost exactly the same size. This significantly increases efficiency with less pesticide use.
The use of drone water will further improve the efficiency of the system. A common feature of “drone water” is that it is a composition made from a mixture of its constituents and the high molecular weight organic polymers attached to it, due to its unique composition, it provides excellent droplet formation. Furthermore, the damage and loss-free “travel ability” of the droplets is a multiple of any aqueous solution, even in strong sunlight. In the epidermis of plants, the surface tension is so low that after 20-30 seconds it completely covers the entire surface and the absorption is so intense that for a significant proportion of pesticides, 2/3 or in some cases half of the permitted dose is sufficient ”.