According to the International Society of Precision Agriculture - ISPA:
The definition of Precision Agriculture recently adopted by the Internatioal Society of Precsion Agriculture is as follows:
Precision Agriculture (PA) is nothing more than the consequence of the information and communication technologies in agriculture or AgroICT. AgroICT allows for the acquisition of data from the crop and its environment, its processing to turn them into useful information and its consideration to assist in the decision making on the management actions to be carried out. Having detailed information on the characteristics of the crop and its environment (soil, climate, etc.) helps the farmer and experienced technicians to make better-informed decisions. Every farmer knows that his/her fields do not produce exactly the same in all their extent. Even so, it is not until these differences in productivity are quantified that the magnitude that this variability can have can be seen. Taking into account this variability in the management of the plots is the goal of the Agriculture of Precision. This information led to the intuition that some fields should be managed not evenly but in a specific way, taking into account the different areas with similar characteristics that can be defined. This type of management is called Site-Specific Management and consists in carrying out farm work, or product applications, or irrigation in a variable way in areas of the plot as required. Moreover, in certain cases, such as in tree crops, you can reach (and it will happen soon!) the management of farms at the level of individual plants.
In summary, Precision Agriculture consists in performing the right operation, in the right place, at the right time, in the appropriate manner and in the right amount. And to do this the following elements are needed:
- Visual observations or observations by means of sensors that allow the acquisition of georeferenced data (that is to say, with coordinates that allow their perfect location on the plot).
- Computerized systems for visualizing and processing data (GIS, geographic information systems).
- Decision Support Systems for decision making.
- Agricultural methodologies or machinery capable of carrying out agricultural operations in a specific way at each point of the plot, what is called VRT (Variable Rate Technology).
The Precision Agriculture cycle could be summarized in the 4 stages that are shown in the following scheme:
The cycle begins with the acquisition of crop data and of its environment. To do this, sensors, visual observations and conventional samples are needed, georeferenced using global navigation satellite systems (SSNG / GNSS). These data can be about the geometry of the crop, the amount of biomass, vigor, soil characteristics, etc. Once the data have been acquired, it is necessary to extract useful information for the farmer and / or the technician. One of the obtained information is if the crop is developed correctly and uniformly throughout the plot. This information will be used in the decision-making stage. This stage is where the agronomic management operations that are to be carried out and in what manner are decided. The first decision is whether we continue to handle uniform field or if it has a variability that recommends differentiated management. This handling implies deciding whether or not to apply a specific resource to the different areas of the field (fertilizer, irrigation, plant protection, planting, etc.) and with what dose to apply it. Currently, this stage is one of the bottlenecks of the AP and the one that requires more research. Finally, you must act in the field to apply the necessary resources or carry out the necessary operations. If the action has to be differentiated, it is possible that we need to use the so-called Variable Rate Technologies (VRT), that allow machinery to modify the application doses in agreement with the prescription developed at the decision-making stage.
The practice of Precision Agriculture can be carried out according to three major methodologies:
1. Precision Agriculture based on digital information maps:
Prior to any agricultural operation, we need to take data from the plot, analyze its spatial variability and map them (create a map of the plot with the spatial distribution of the measured variable). After analyzing the maps you have to make a decision to handle. The result of the decision-making process will be a new map, called action map or prescription map, which shows what must be done at each point of the plot (intensity of the operation or dose of product to be applied). Normally, it will be an electronic controller boarded the tractor who will determine what to do at each point and a team equipped with variable performance technology that performs it. In order to practice this type of agriculture, it is indispensable to have a positioning and navigation system (commonly called "a GPS") more or less precise so much for the taking of data as for the action. For example, one could think of the application of an herbicide from a prescription map indicating the need to apply or not based on the presence / absence of a certain weed and the dose to apply.
2. Precision-based precision Agriculture and in real time:
This type of agriculture strictly does not require positioning and navigation systems since the taking of data, the decision and the action are carried out in real time while the tractor and the equipment are moving through the plot. Since the performance will continue to be variable, the team must also be equipped with variable performance technology. The difference is that the performance is not based on a prescription map but on one or more sensors that are taking "on the fly" data. As an example, in the herbicide application described in the previous case, it would not be based on a prescription map but on the detection, in real time, of the weed in question from the measurements obtained by a sensor at that same point.
3. Fusion of the previous two.
While map-based systems allow many more variables to be taken into account and perform much more complex analysis than sensor-based and real-time systems, the latter allow a much faster reaction to situations that require diligent actions.
The practice of Precision Agriculture allows to improve the profitability of the exploitations through the improvement of their management. However, the analysis of the data and a correct decision-making could even improve the quality of the productions or the final products, reduce the risks of the operations, be able to perform a correct traceability of the operations and of the productions, reduce the environmental impact of agricultural activity and, ultimately, increase the sustainability of the farm.
On the other hand, bringing Precision Agriculture into practice requires additional training of farmers and technicians in data acquisition and processing and in automation and control technologies applied to agricultural machinery.
However, before implementing Precision Agriculture strategies, it is necessary to analyze in detail the costs and benefits that this entails. It is true that Precision Agriculture is associated with expensive and "Hi-tech" equipment. However, initial investments must be analyzed taking into account their profitability, in terms of product or water reduction or improvements in the productivity and / or in the quality of the harvest. Another aspect to keep in mind is that it is also possible to practice Precision Agriculture without having too much technology. As mentioned above, it is about applying agrochemicals or water wherever necessary and in the required quantity and this can be done with very simple tools. It will all depend on the dimensions of the plots and the availability and cost of labor.
Currently, the challenges of Precision Agriculture are to facilitate the decision making for all types of crops and achieve their massive commercial implantation. That is why researchers, advisory technicians and equipment manufacturers have to unite efforts to show farmers and society the advantages of this agriculture, which should undoubtedly be the agriculture of this century XXI.
The devices linked to the Precision Agriculture that are most accepted are the guided help systems. These systems are relatively simple and affordable and represent a clear improvement in the eyes of the farmer: perfectly parallel paths without external references and elimination of overlaps and areas without planting or treating or fertilizing. It should be noted that its implementation has gone hand in hand with the generalization of navigation systems in private vehicles (GPS). However, the use of a guided help system, or even automatic guiding systems, is to apply a small percentage of what the Precision Agriculture represents.
Another aspect to take into account is how will the agricultural machinery be in the future. One of the advances is the construction of large equipment for large tractors. These super equipment clearly increase the work capacity and performance of the operator but involve disadvantages such as its high cost of acquisition and maintenance, possible problems of compaction caused by super tractors as well as reservations in the accuracy of operations by wanting to work faster and better. In contrast to this line, there is the view that future farms will be cared for by small robot fleets working cooperatively. This eliminates employee dependence and the need to work quickly and that robots can work up to 24 hours a day and can take time to perform tasks that require accuracy. This option, however, looks a bit more futuristic and raises some doubts. An intermediate option that is already in the market is the use of "master-salve" equipment sets. The idea is to use medium equipment stuck to two or more medium tractors working simultaneously. One of the tractors is manned and exercises as a reference ("master"). The other tractor (s) are unmanned and mimic the trajectories and actions of the first with a certain time and space gap. In this way, more surface is covered without having to resort to exaggeratedly large equipment, achieving more maneuverability and maintaining the supervision of an operator
Precision Agriculture is called to be the agriculture of the 21st century. However, its commercial implantation is uneven according to the type of crop and it is taking a long time. It must be taken into account that the major changes need time to generalize and, if not, how long did it not have to pass from the development of the first tractors to the total implantation?