Mapping, weeding, harvesting: the role of drones in agriculture
Despite some technical and regulatory issues that have yet to be definitively resolved, real-time monitoring of numerous environmental and crop parameters and selective distribution at variable rates are currently the most successful uses of drones in the agricultural sector. To the benefit of a qualitative improvement and a more effective sustainability of production
Also known as UAVs (Unmanned Aerial Vehicles), drones are remotely controlled unmanned aerial vehicles, which lend themselves to a wide range of applications. They are also used in the agricultural sector, thanks to the possibility of performing low-altitude flights to acquire images, record videos, collect useful data and transmit information for monitoring and managing crops. The drone is typically composed of a lightweight structure with wings or more frequently propellers, allowing it to fly while maintaining stability and maneuverability during air navigation. The motors, electric, are high efficiency and low noise, and are battery-powered.
The different types of drones. The different propeller configurations available result in significant variations in performance, stability, and load capacity. Tricopters (with three propellers) can be used for stunts, FPV flights (First Person View flights, i.e. piloting the drone through images taken by a camera installed on the drone, while the drone is outside its field of view) and action camera shooting. The 4-propeller models – the quadcopters – are more popular and versatile, economical, stable and easy to fly; they are optimal for aerial photography and amateur and semi-professional level video shooting. Hexacopters (6-propellers) and octocopters (8-propellers), on the other hand, are equipped with powerful motors and long-lasting batteries, offer greater stability than quadcopters and are mainly used for professional shooting with heavy equipment. The remote control is implemented with dedicated remote controls, to adjust altitude, direction, speed and numerous other specific functions. A wide range of devices and accessories can be installed on drones: GPS navigation systems, cameras, video cameras, thermal imaging cameras and sensors of all kinds. The data collected can be stored on memory media placed on board or more frequently transmitted in real time to the ground, and also analyzed with the help of Artificial Intelligence, to assess the state of the cultivated plants, then making the consequent operational decisions.
One of the most popular applications is the use of NDVI (Normalized Difference Vegetation Index) sensors to monitor the health of plants, detecting diseases and water stress. Thanks to specific algorithms, physical information is converted into agronomic indicators, identifying the causes of problems, taking into account the characteristics of the crop in progress, the tillage carried out, the characteristics of the soil and the climatic trend. Mapping or monitoring makes use of specific flight planning software, aimed at defining trajectories and automating camera footage.
The challenges... Although promising, the use of drones in agricultural contexts poses challenges and risks that must be carefully considered. One of the most obvious critical issues is represented by the load capacity, which at the moment cannot exceed a few kilograms, thus placing limits on the instruments and devices that can be used on board. The problem related to the reduced load capacity is also reflected in the flight range, limited by the need not to overcharge the vehicle with heavy (and bulky) batteries. Increasing the operational autonomy of drones is therefore a fundamental technological objective, but it still requires significant developments in batteries and, more generally, in energy management systems. In addition to these technical challenges, there is still some regulatory complexity regarding the use of drones in agriculture, including restrictions on the height of flights and the requirement of specific authorizations to operate.
The use of drones also entails significant upfront costs, both in terms of the purchase of aircraft and the education and training of personnel. These are economic burdens that can be a barrier for small farms, limiting access to advanced technologies and potential productivity improvements. A further challenge, which is also of a general nature, is represented by the integration and interpretation of the data produced by the sensors and devices installed on drones. The large amount of information collected requires the adoption of advanced software platforms, and the acquisition of specific skills for data analysis. By the way, it should not be forgotten that drones are particularly vulnerable to cyber threats and can easily be subject to theft.
... and the benefits. Real-time monitoring of plant health and plant needs makes it possible to optimize the exploitation of precious resources such as water, fertilisers and plant protection products, avoiding waste and harmful dispersion, with additional benefits of a social nature, given that precise irrigation planning and the careful and responsible use of fertilisers and pesticides contribute to environmental sustainability. Of course, the environment is grateful, but in a context where food safety is a growing concern, consumers are also guaranteed better quality products, often at more affordable prices. Finally, we must not forget the important role that the use of drones plays in the field of scientific research in agriculture. Among the many opportunities, the data collected is also valuable for monitoring climate conditions, studying environmental changes and preserving biodiversity, for effective environmental protection and sustainable management of natural resources.
Technologies and applications. Current solutions in the use of drones for crop monitoring are mainly based on remote sensing, i.e. the acquisition of multispectral and hyperspectral images using optical sensors. For example, in wooded contexts, phytosanitary monitoring is carried out to identify parasites that cause evident defoliation, such as the Processionary, the Tentredine and the Ifantria, which are easily detectable from above.
In addition to data collection, drones in agriculture can also be used to carry out some processes, including those related to phytosanitary treatments. Bearing in mind their operational limitations, however, drones are already profitably used for targeted interventions, such as for example for the fight against the corn borer through the distribution of Bacillus Thuringiensis, with localized administration on identified outbreaks. Further similar experiments concerned the distribution of insecticidal baits for the control of the olive tree fly and for localized weeding, both in agricultural and non-agricultural fields, such as in golf or football fields.
Italian companies. Developed by Italdron of Ravenna and Adron Technology of Udine, the Agrodron drone has a mass of 5.5 kg at take-off, a flight autonomy of about 18 minutes, and is able to carry a container that releases cellulose capsules with agricultural products. It is therefore used for the biological control of pests, such as the corn borer, for a targeted alternative to traditional solutions, based on the use of a specific equipment combined with the tractor. To ensure precise distribution of the capsules, the drone uses a radio-controlled control system with autopilot and GPS RTK.
Similarly to countries such as Chile, Israel and the United States, where this practice is already well established, there is also a growing interest in harvesting fruit with drones in Italy, especially those placed on the highest branches, which are difficult to reach by hand. Tevel Industries, one of the leaders in the sector, offers Flying Harvest Robots, drones intended for harvesting apples, peaches, plums, apricots and pears. They are enabled to use advanced perception algorithms in an Artificial Intelligence (AI) setting, to identify fruits in the middle of foliage, classify them according to size and degree of ripeness, and determine the optimal approach to harvest each fruit without causing harm. The fruits deemed suitable for harvesting are then detached from the trees by means of suction cups mounted on mechanical arms, which are also guided by AI. Afterwards, the fruits are gently deposited on a self-propelled platform that transports them directly to the warehouse. Designed to maximize efficiency, these robots are able to harvest different fruits, throughout the year, operating in different types of orchards with various row configurations. In addition to this, they can provide real-time data about the amount of fruit harvested, weight, color gradation, degree of ripeness, diameter, time of picking, geolocation, and other useful information
Swarm drones. This is a large number of small machines (even a few tens of kilograms each) that work in a coordinated way, performing specific tasks and communicating continuously with each other. The use of swarm drones has several advantages, especially in terms of operational flexibility. In fact, while a single large drone might have limitations in agility and the ability to cover a large area, a swarm of drones can spread more efficiently over a relatively large area, improving the overall effectiveness of harvesting. In the agricultural context, for example, compared to a single vehicle, the use of a swarm of drones makes it possible to eliminate weeds more quickly in a selective way, with mechanical or even chemical techniques, in the latter case with a consequent reduction in the dispersion of chemicals into the air and on the ground. Another fundamental aspect of agricultural activities is the timeliness of intervention: in the event of a failure of one of the drones within the swarm, the others can easily compensate for the loss, maintaining the continuity of operations without significant interruptions. If, on the other hand, you opt for the operation of a single large drone for the entire task, any malfunction or failure could cause the entire harvesting operation to be interrupted, causing delays and economic losses.
Future evolutions. The successful application of machine learning (deep learning) and then AI will make agricultural drones more efficient and adaptable, adapting their intervention to changing conditions of the ground, climate and environment. Moreover, the improvement of the so-called "energy density" of batteries (i.e. the capacity to store electrical energy in the unit of weight or volume) is significantly increasing the autonomy of drones, making longer and more complex missions possible. However, further progress is needed in terms of standardisation and interoperability, facilitating integration with other data sharing systems, as well as the development of rules and regulations aimed at ensuring a secure and reliable operating environment.
Italian legislation
In Italy, the use of drones in agriculture is regulated by Legislative Decree 18 February 2021, n. 25, which adopts the European Regulation on Drone Operations (UAS). This decree defines the rules for the operation of drones in the European Union, including those used in agriculture, and covers aspects such as registration and identification with ENAC (National Civil Aviation Authority), the division of drones into categories with specific operational requirements, altitude limitations, flight restrictions in certain areas, mandatory insurance, certification and training of pilots, as well as the authorizations necessary to operate in specific contexts such as urban areas or public events.
Qualification to drive drones
In order to be able to fly drones with an operational take-off mass (i.e. the total mass of the drone, including any devices and accessories integral to it, such as a camera) between 0.25 and 25 kg, it is mandatory in Italy to be in possession of the so-called "license" (Certificate A1-A3).
Along with this, the registration of the pilot and the registration of the drone on the D-Flight portal is also mandatory, as well as the opening of a specific insurance policy.
Conversely, drones that exceed 25 kg are considered as traditional aircraft and, therefore, due to their condition it is mandatory to have the Aeromodeller certificate, issued by the Aeroclub of Italy.
