Precision farming machinery: the current scenario
Agricultural mechanics have always gone hand in hand with agronomic techniques, providing technological solutions to make work more efficient and the use of productive means more rational. A combination that has made it possible to meet the historical needs of an ever-changing agriculture that will continue to do so in future, consolidating development models able of rationalizing the use of natural resources through innovation and research
If we consider the agriculture’s development trend from 2000 to now, at least as far as the agricultural machinery sector is concerned, it can be noted that the most significant event was the introduction of new technologies related to information technology and electronics. Precision farming can be synthetically defined as a management approach based on variability and modern technologies aimed at increasing the efficiency of production processes with a view to minimizing costs and protecting the environment. The introduction of this new management system requires advanced sensor technology, data transmission networks, modeling, telecommunication of geo-referenced information, decision support systems, implementation of automation and digital prescription maps, displays interfacing with the operator, traceability in telemetry of operations, processing and feedback of sustainability indices. All integrated together. Some different approaches have characterized the response of the Italian agricultural world confronting this wide technological availability of the market: the first involves the direct use of sensors and onboard computers for machine control without necessarily involving the human factor (mechanization of precision); in the second one the operations are programmed by the user through the study of thematic maps and the production of prescription maps (precision farming as such).
Precision based on GNSS
The so-called precision mechanization provides forms and functions of direct control of the machinery through standardized procedures that do not use prescription maps, but which are based on GNSS, sensors, and Isobus. There is, therefore, no need for external agronomic competences to manage variability, and the system generally produces certain benefits, which are easily understood by entrepreneurs.
In other words, in this case, we will have to get used to highly reliable and relatively simple technologies, from a mechanical point of view, but equipped with complex service networks to interact with the components that characterize agriculture: soil, plants, animals. A big boost will come from the introduction of new sensors. In fact, they can allow the agronomic techniques to adapt to the intrinsic variability of the soil, of the environment and therefore of the crops. Driving systems with GNSS are the "driver" sector, where business volumes are currently higher. The spread of the guide kits with bar and LED lights to be installed aftermarket is flat or slightly down, but for the benefit of semi-automatic driving of the electric or hydraulic type currently in constant growth. The advantages of satellite navigation taken as a stand-alone system are well known, but they can be amplified if an Isobus system is combined with the GNSS.
The ISOBUS technology provides users with customized protocols for the control of tractors and machinery such as the Sequence Controller, the Task Controller and, lately, TIM (Tractor Implement Management).
The former is applied for the automatic creation of sequences of repetitive turn operations between one pass and the other.
The latter can selectively manage the delivery of the products on sections, nozzles and rows on seeders, sprayers and fertilizer spreaders, implementing thus the automatic control of the sections or ASC (Automatic Section Control). ASC uses a GNSS to locate the position of the machine and then registers the worked areas. If the machine passes through a previously worked or untreatable area, dispensing is deactivated, thus eliminating over-application. The TIM system allows the machine to control some specific tractor functions, such as the feed speed or the pdp rotation speed.
The achievable product savings are worthy of note and depend on constructive and structural characteristics. The greatest advantages are obtained when the working width of a controllable section is low, i.e. it is divided into a large number of sections. In addition, the savings are greater the lower the surface of the plot is, and the more irregular its shape.
Of course, this functionality affects the cost of the machinery, but the control of the sections is the first step towards the so-called variable rate distribution.
More and more opportunities are offered by standardized communication protocols in tractors and agricultural machinery (ISOBUS).
Together with satellite receivers, the technological evolution has led to the presence of many sensors, managed through the onboard computer, to support the monitoring and/or automation of both the tractor and the operating machinery.
All this has been translated into the development of automation systems based on technologically more and more sophisticated actuators.
In this sense, applications for extensive crops concern, for example, the real-time control of the uniformity of seed deposition for monogerm precision seed drill, the variation of soil tillage for pdp-driven operators, variable-dose fertilizer with centrifugal fertilizer spreader equipped with multispectral radiometers, inter and intra-row mechanical weeding for horticulture with optical sensors, flow control and forage density control in giant packing machines, etc.
In sprayers, position sensors positioned upstream of the regulators, allow to detect the presence of the "target" and its position and, consequently, to interrupt or vary the flow according to the presence and characteristics of the vegetation (spot spraying), with obvious additional product savings.
Precision based on maps
The three fundamental steps for adopting precision agronomical practices based on maps are: spatial data collection to characterize and identify homogeneous areas within the field; data analysis to interpret the causes of spatial variability; implementation of the decisions taken on the differentiated agronomic practices to be adopted. It is a more complete, but also more complex and articulated approach because it requires the creation of maps of the ground (with sensors of conductivity or electrical resistivity), vegetation (with sensors near the crop or remote using radiometers positioned on satellites, aircraft and drones), or the characteristics of the productions through the installation of a yield mapping system to detect the quantity and some qualitative characteristics.
After the analysis of the collected data and the subsequent decision phase, the prescription map is transferred to the operators for realizing the variable application of the productive factors (VRA).
For this, the equipment must be equipped with an electronic dose regulation system (DPAE) and with all the previously mentioned devices such as the satellite receiver, an Isobus communication system, flow sensors, and actuators.
Some achievements are already on the market such as the row or monogerm seed drills with electric dosing units, centrifugal and pneumatic fertilizer spreaders with DPAE and variable distribution, sprayers with sensors for the recognition of weeds and dose variation, recovery or mobile wing irrigation systems.
These new technologies are starting to make their way into the market with ever higher percentages of models that install standard systems to make precision farming possible.
This is a clearly slow process, also in light of the quantity and of the very high average age that characterizes the agricultural machinery fleet in Italy.
A driving factor
The process of conversion to precision is certainly slow, but could soon be fueled by the increasingly sought-after quality demand in the agri-food sector.
The intrinsic value added of more sustainable and environmentally friendly products (such as those produced using precision farming techniques) can now be enhanced through new devices that promote traceability of processes and monitoring of agricultural practices adopted.
These devices therefore not only support the entrepreneur with the automation of the compilation of the registers and logbooks but in some way they allow a certification of the practices adopted, giving the final consumer more information and more guarantees: which can more quickly repay the farm of its modernization efforts.
by Luigi Sartori e Francesco Marinello