Some crops to be mechanized require machines with smaller dimensions, such as the R50 tractor from LS Tractor, which was designed to work in the cultivation of grapes, apples, pears, persimmons and peaches.
The mechanization of fruit growing involves, to a large extent, the supply of tractors capable of working in specific conditions inherent to this activity. The wheeled tractor, specifically, is an agricultural tractor, with at least two axles, where the means of propulsion consists of wheels generally fitted with rubber tires. Tractors can be used in various functions in both agriculture and livestock. Above all, a large part of its use includes work on annual agricultural crops of herbaceous size, such as wheat, rice, corn, soybeans, among others, but also on semi-perennial crops of shrubby size, which prevent the traffic of machines over them, requiring the use of spaces between plants and these arranged in rows. This is the case of crops such as coffee, citrus, apples, peaches, grapes, among others. Thus, fruit or compact tractors appear, which are considered special for agricultural use. The ISO 3463 Standard defines them and differentiates them from “standard” tractors by their reduced track, that is, less than 1.150mm on the rear wheels.
In the Brazilian market, these tractors are known generically as “narrow”. In the past, several of these models were simply known as “coffee makers”. However, not all narrow tractors are necessarily special tractors. For crops such as coffee, citrus and apple trees, gauge reductions of approximately 1.400mm already allow the work to be carried out without major problems. For vines, peaches and plums, there is a need to work with minimum usable widths of less than 1.200mm, which requires gauges of less than 1.150mm.
Fruit crops differ substantially in road dimensions, distance between plant rows, and spacing between plants within crop rows (rows). For example, apples in Serra Gaúcha are cultivated in a system of 4,10m between rows, resulting in a distance between plants of approximately 1,60m, since the plants develop in the direction of the row and between rows. The average height of the plants is 2,80m, allowing the use of taller tractors, including those with a protective arch, as long as the maximum width does not exceed 1,50m, to avoid impacting branches and branches.
However, in the cultivation of plums and peaches the condition is completely different and requires tractors with a maximum height of 1,60m to 1,70m, as the driving system causes a tunnel to be formed. The spacing between rows is approximately 4,90m and the maximum width of 1,50m is a condition so that the tractor does not bump into branches and fruits, mainly.
In vine cultivation, the situation is aggravated, as in the trellis training system there is a roof, a horizontal arrangement of the canopy, formed by a wire that supports the branches and, mainly, in the production stage, the bunches with the grains. This horizontal barrier makes it difficult to move machines. Since the space for moving the machines is confined between width and height, resulting from the arrangement of the plants in the rows of pillars, approximate spacing of two meters to 2,10m between rows and height of the horizontal wire between 1,60m to 1,80, XNUMXm. It must also be considered that most areas are located on slopes and, as a result, the height in the bottom row is always lower than in the top row. In fact, this is the reason why some producers create levels, in order to level the spacing between rows.
In view of this, some tractors can be adapted according to their intended use and considering special conditions. The basic adaptations that can be applied are summarized in the distance between axles, track and height of the highest point on the ground. Changing the distance between axles results in changes in longitudinal stability and changes in track and ground height result in changes in the lateral stability of the tractor when working.
In narrow tractors, the width dimension is small, a reflection of the small gauge, consequently causing transverse stability problems in situations of sloping terrain, which requires minimizing the height of the tractor and maintaining the frontal area. An agricultural tractor used in fruit growing or semi-evergreen crops must be low enough to avoid damaging leaves, branches and hanging fruits, in addition to being small in height to increase its stability. As we have seen, in some fruit crops, in addition to the width restriction, sometimes the total height of the tractor is a very restrictive and even impeding factor for operation.
As a result, LS Tractor, through its dealers and customers, received the demand to adapt a tractor, mainly for vine cultivation, predominantly carried out using the trellis system in the southern region of Brazil. However, when developing its information system with the requirements presented by customers, it found that these adaptations could be used for other crops such as plums, persimmons, apples, peaches, as well as for use in poultry farms, which also require machines with reduced dimensions.
Verifying that this was a demand more aimed at customers of the R series, specifically the R50 model, it sought to activate its engineering department and focus this work on substantially reducing the total height of the tractor, through reducing the diameter of the tires, reducing the height of the seat, removal of the vibration attenuation system and reduction of the platform height, with lowering of the foot support plane. This change to the original design resulted in other modifications such as the redesign of the brake pedals and the access step to the driving position, in addition to the removal of the conventional protective arch that equipped this model in its original version.
Since, in this model of tractor, the fuel tank is at the back of the driver's seat, when reducing the height of the seat base the tank protruded in relation to it, but did not require movement or replacement.
In the normal version, the maximum height corresponded to the distance between the ground plane and the top of the safety arch with a dimension of 2.407mm, preventing any movement in an environment with horizontal span restrictions, as described.
The engine fitted to this tractor is the LS brand, model S4QL, four-cylinder, 2.505cm3, mechanical and direct fuel injection and natural aspiration. It meets the Tier 3 emission control standard and provides 50 hp of maximum power, according to the ISO TR 14396 standard, at a speed of 2.600 rpm. Maximum torque is 147Nm, reached at 1.600rpm. It is worth noting that the opening width of the front hood facilitates periodic and corrective maintenance.
As for the transmission of power and torque, this begins with a mechanically driven clutch that uses a disc made of organic material. The gearbox is of the Synchro Shuttle type, equipped with a super-reducer (Creeper), providing 32 forward gears and 16 reverse gears, with reverse direction. The Creeper doubles the number of forward gears and provides very low travel speeds for special operations that require this option.
The supply of power in rotary movement is made by the power take-off (TDP), which is of the independent type with electro-hydraulic drive and three angular speeds, the standard and most common being 540rpm, 1.000rpm and the economical mode which is the angular velocity of 750rpm.
Regarding the use of power in hydraulic form, it is possible to take advantage of it in two ways. The first way is through the three-point hydraulic lifting system, category II, with a total flow of 47 liters per minute and a maximum pressure of 200bar, reaching a lifting capacity of 1.800kgf, measured at the arm joint joint. lower. Therefore, its drive and control system is the conventional two-lever system with position and depth control. The second way of using hydraulic power is through the valves of the independent remote control system (VCR), which can be two in the standard version and three as an option, with a maximum flow of 31 liters per minute.
The brakes consist of two oil-bathed discs, with mechanical actuation, and a lever-operated parking brake. Furthermore, this tractor features auxiliary front-wheel drive (TDA), with a driving front axle, which can be disconnected using an electro-hydraulic control. The axis movement system is shielded and differs from conventional ones (with crossheads), in addition to providing less maintenance and reducing the turning radius. For better handling and traction, with the set of radial tires that equip this model, the internal tire pressure must be 30psi on the front wheels and 20psi on the rear wheels. Thus, the static weight distribution between axles is 47%/53%, front and rear respectively, resulting in a kinematic ratio between axles between 2% and 4%, which is very favorable. On the rear axle, between the differential and the wheelsets, there is an epicyclic final reduction. In fact, the differential lock is mechanical.
To prove the effectiveness of the modifications made by LS Tractor engineering, the Revista Cultivar HF team visited two families, LS customers, in the Serra Gaúcha region, more specifically in the town of São Gotardo – Capela, District of Vila Seca, in Caxias do South, customers of the regional dealership, Trator Serra.
The first location was a vineyard area, owned by the Bassanesi family, where four brothers produce grapes for juice and wine, the burgundy variety, on the trellis system, and which are delivered to wineries in the region.
The four brothers, João Fernando, Pedro Antônio, José Leonardo and Ivo Roque Bassanesi, own 11 hectares, of which nine correspond to an area established 21 years ago, and another smaller area, close to the family residence, established more than 30 years ago. by their grandfather. They use a system in which the spacing between lines is 3m, 2,70m between plants, with the external street for transport measuring 4m and an average wire height of 1,70m. Consequently, it is an excellent system for maneuvering machines and is gradually beginning to be prepared for the implementation of an interim plant in the existing row. The support and tensioning platforms for the wire structure, partly made of itaúba wood and concrete, are excellent in terms of maintenance.
According to what the brothers told us, initially they had other brands of tractors, which were cumbersome to operate and required more work. Today these tractors are only used for transport, as with the modifications to the LS R50 they began to use it for tasks that require movement within the area, mainly for the application of fungicides and insecticides and cleaning the streets and between lines through the fields.
We visited the area during the flowering period, which lasts throughout the month of November. At this stage of development, routine treatment with fungicide and insecticide is intense, mainly to control the caterpillar, management associated with foliar fertilization with macro and micronutrients, activities that last until January, in addition to NPK fertilization on the foot carried out at the beginning of November. According to the Bassanesi brothers, the trellis system creates a microclimate, which, while hindering mechanization, promotes the appearance of diseases and pests. Furthermore, ants are another problem that they solve by applying granulated anticide to the path, especially on dry days, when it is more effective.
One of the producers' concerns is that when emitting grain, “the grape takes away the product”, that is, any hesitation in the fight against diseases and insects will mean losses in production. Also, with some frequency in the summer, they clean the area by controlling invasives through mowing and applying herbicides to the plant line. At the end of the cycle there is always concern about the danger of heavy and windy rain, in addition to the feared frost, which occurred heavily last year. To prevent frost, the family implemented an irrigation system against frost in the area close to the houses and the result last year was rewarding, as approximately 38.000kg per hectare were harvested from these two hectares, otherwise it would have harvested less than 1.500kg per hectare. hectare. Frost and hail insurance, with federal subsidies, is an opportunity for farmers.
The harvest takes place in February and involves the whole family, including neighbors, as it requires ten to 15 people and lasts approximately 20 days. The property is transported to the reception point by truck, with the body covered with aseptic canvas.
After a period of less than 45 days, the family returns to daily work to maintain the structure.
In July and August one of the most important activities in vine cultivation begins, which is pruning, again with the help of the whole family. The local custom is to leave a variable number of buds per branch, depending on the vigor, approximately six or seven buds. In conjunction with pruning, the family ties up the branches that will produce, done with tape using their own machine or with plastic-coated wire.
The maintenance of the wire and the replacement of posts and tensioners occur throughout the year, with the only possibility of vacation in the months of March and April, even so the family alternates between periods.
Although the routine is quite arduous, the brothers enjoy the activity and will only stop when they retire. The team was renewed recently, with the entry of Edelvan Schmeling, son-in-law of Mr. João Fernando, who has a partnership with his brother Pedro Antônio and is the operator of the new tractor.
As for the new tractor, the family has nothing but praise, as the motivation for the purchase was the lack of a special vehicle that would facilitate activities carried out in places with reduced space and height. A field demonstration carried out by the Trator Serra dealership on the neighboring property was decisive for the acquisition of the R50. In previous harvests, phytosanitary treatments were carried out using another tractor, which caused inconvenience and increased fuel consumption. Now, according to them, operating comfort is much greater, mainly due to the lower height and electro-hydraulic controls. For them, the adaptation has greatly improved their quality of life and there is still no perspective regarding maintenance, as the tractor only worked 50 hours and did not require any activity in this regard.
The acquisition made at the Trator Serra dealership was made with a cash deposit and the remainder with direct financing from the company. According to Mr. João Fernando, there is a difficulty for children to succeed their parents in agricultural production, as urban work opportunities are quite attractive and only agricultural mechanization, bringing security and comfort, is capable of keeping youth in the countryside.
The second area visited was that of the Zanette family, who manage Zanette Frutas. Agricultural Engineer Gian Carlo Zanette welcomed us to show the systems adopted by the company in the areas they cultivate with persimmons (5ha), peaches (5ha), plums (1,5ha) and grapes (7ha) for juice and wine that they send to markets from outside Rio Grande do Sul, mainly Paraná and Minas Gerais.
The family made up of Gian Carlo's father, mother, sister and grandparents acquired the area in 2017-2018 and, since then, has been implementing crops with a lot of technology and based on the best production techniques. For them, the biggest difficulties in this type of production are the harvest, which extends over several months of the year, from November to January for peaches and plums, grapes in February and persimmons in April, in addition to the various treatments necessary to contain diseases and insects. that depend on good and well-regulated machines. Another difficulty is peach thinning, which often requires the use of ladders and body protection.
After harvesting, the product is stored for a while in its own cold room, preparing it for outsourced transportation.
Like the Bassanesi family, the Zanettes are very satisfied with the modifications made to the R50, indicating a solution to a mechanization problem they had, mainly in grapes and peaches.
At the time of the visit, a localized irrigation system was being installed, which will reach 100% of the area this year, guaranteeing the production levels they intend.
At the end of the visits and after trying the tractor in different situations, we found that customers are satisfied with the modifications made to the original model of the LS R50 tractor and that perhaps without these it would not be possible to mechanize these areas, especially in the vine, in the cultivation of peach and plum. Even with an operator of normal height, the maximum height was not reached. We also realized that no vital function in the operation was reduced or harmed by the redesign, which preserved the ergonomics of the operator's station, keeping the main controls and functions accessible.
Jose Fernando Schlosser,
Walter Boller and
Daniela Herzog,
Federal University of Santa Maria
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