Adequacy of agricultural machinery

The suitability of tractors for the activities to be carried out is a basic necessity, as an error in ballasting, for example, could compromise the operation to be carried out.

When purchasing agricultural equipment, be it a tractor, a machine or implement, the rural producer is faced with a range of possible adjustments to this equipment, all explained in the operator's manual. What many don't know is why, why and why these changes are necessary.

A classic example is tractor ballast, as many producers ask themselves what it is for, when it should be added or removed, whether they are benefiting or losing, whether they are operating at the correct speed and whether the internal air pressure in the tires is correct. . All these questions that haunt the producer's head have answers in the suitability of the machine.

Adaptation consists of a set of modifications to be made to equipment in order to make it suitable and receptive in different conditions. For example, an operator is going to carry out subsoiling, an activity considered heavy, he must then add more ballast to the tractor to reduce wheel slippage and, consequently, the loss of tractor power.

CHARACTERISTICS/BENEFITS OF ADEQUACY

Currently, the search for increased efficiency is evident in all production sectors and one of the ways to increase efficiency when working with agricultural machinery is by adapting the tractor to the implement it is attached to (Santos, 2010), in addition, the correct adaptation it also reflects in greater work capacity and lower fuel consumption (Mialhe, 1974), the latter being one of the highest costs in agricultural operations.

The suitability of agricultural tractors is directly related to the weight of the tractor and, for an implement to be used rationally, it is also necessary to know the soil conditions it will meet (Mantovani, 1999). In theory, for each soil condition there would be a need for a different adaptation for the same tractor-implement set. The wide variety of agricultural machines available on the market must also be considered, enabling the farmer to choose the best combination to meet his demand.

Therefore, if the tractor-implement set exceeds the required power demand, there is an increase in production costs, because the equipment was underutilized. Conversely, if the tractor-implement set does not meet the necessary power demand, operations may not be carried out, as the tractor will not be able to pull the agricultural equipment, which will cause losses. In practical terms, in heavy operations, a tractor with little ballast can present high rates of slipping, increasing tire wear and reducing operation efficiency, while a tractor with excess ballast can cause soil compaction (Barbosa, 2004).

Agricultural tractors can be ballasted by adding water to the tires and/or with metal parts placed on the wheelsets and front of the tractor. In some tractors, metal ballasts are used on the outside of the wheelset and, in others, metal ballasts are placed on the inside and outside of the wheelset. However, the operator does not usually remove or add metal weights to meet weight needs, because it is a task that requires time and physical effort.

Insufficient ballast can cause problems such as excessive wheelspin, loss of power and traction, severe tire wear, high fuel consumption and low operational productivity. Excessive ballasting, on the other hand, can cause problems such as increased load on the transmission, loss of power and traction, rupture of tire claws, soil compaction, high fuel consumption and low productivity.

Monteiro and Arbex (2009) report that a few steps are used for correct adaptation, the first is the weight/power ratio and this determination is made based on the operation to be performed. The weight of the tractor should be its power times 50, if it is a light operation; 55, if it is a medium operation, and 60 if it is a heavy operation. Taking subsoiling as a basis again, a heavy activity, with a 120hp tractor, then the weight of the tractor must be 7.200kg.

The weight to be distributed on the tractor's axles will depend on the operation to be carried out and the type of tractor, all depending on the weight/power ratio, so operations mounted on a 4x2 tractor will have different distributions than an operation with heavy duty equipment. drag on the same tractor. These values ​​are presented in Table 1. Thus, if a 4x2 tractor weighing 5.000kg is going to carry out a light operation with dragging equipment, its weight distribution will be 1.250kg on the front axle and 3.750kg on the rear axle.

Another important aspect to be considered when adapting agricultural tractors is the adjustment of the operating platform components. However, research carried out demonstrates the need to adapt tractors for Brazilian rural workers. The area of ​​agricultural mechanization has a characteristic of ergonomic inadequacy of tractor systems, as they use technology from other countries.

The ergonomic quality of the product includes ease of handling, anthropometric adaptation, clear provision of information, movement compatibility and other comfort and safety items, which justifies its application in the context of agricultural machinery. Improving safety and comfort conditions for the agricultural tractor operator can contribute to increasing productivity (Vilagra, 2009).

In general, a tractor well suited for the desired operation, with correct distribution of weight on the axles, adequate internal tire pressure depending on the load on the tire and with recommended slip for the type of contact surface, brings fuel economy benefits. , saving time in operation, less tire wear and mainly a reduction in soil degradation.

Soils prepared with overweight tractors tend to be compacted more quickly, so fewer tractor passes are needed to increase soil density. Not only does the tractor's overweight have an influence, but the use of speeds that are inappropriate for operation can also aggravate the situation. This occurs due to excess weight per unit area during a certain period of time, as tractors at lower speeds tend to become more time over the same point, making the situation even worse.

With modern agriculture, adaptation is no longer optional but becomes essential in a system that increasingly seeks excellence with minimal loss in a sustainable way.

Jefferson Auteliano Carvalho Dutra, Deivielison Ximenes Siqueira Macedo, Leonardo de Almeida Monteiro, Viviane Castro dos Santos, Daniel Albiero, Enio Costa, UFC

Article published in issue 161 of Cultivar Máquinas.