Use of tractors in rice cultivation

Sampling carried out among irrigated rice producers in Rio Grande do Sul reveals that the majority of tractors used in the crop are in good or excellent condition.

Rio Grande do Sul stands out as the largest national producer of irrigated rice, being responsible for more than 60% of the total produced in Brazil, with an area of ​​more than one million hectares (ha) cultivated. The Western Border region stands out for being the largest producing region in the state, responsible for more than 300 thousand hectares (Sosbai, 2012). In this region, irrigated rice is cultivated on a surface with controlled unevenness, and almost all areas use the conventional cultivation system, which requires a large number of operations from soil preparation to harvesting.

Due to adverse weather conditions and cultivation in leased areas, where beef cattle occupy the plots until the months close to sowing, the time window for carrying out operations is reduced. In this context, the main alternative is to increase operational capacity so that several operations can be carried out simultaneously. Therefore, it is necessary that agricultural machines are in good operational condition when requested, so as not to cause delays in the execution times of operations. According to Khodabakhshian (2013), only by monitoring equipment conditions is it possible to establish a management plan with a view to optimizing the fleet. In this context, the objective was to characterize the tractors and mechanization index (MI) used in the cultivation of irrigated rice in the Western Border region of the state of Rio Grande do Sul.

The research was carried out on 11 agricultural properties distributed in the Western Border region of Rio Grande do Sul, in the municipalities of Alegrete, Quaraí and Uruguaiana, totaling a productive area of ​​4.144ha. The methodology was based on the identification and collection of information from 71 agricultural tractors, obtaining data regarding the brand, model, traction system, the presence of a cabin or rollover protection structure (EPC) and the external state of conservation, It is rated as good/excellent when there are no scratches or dents, fair when it has scratches or loss of natural shine and in poor condition when it has scratches, dents or the absence of original parts. The cultivated areas on the properties were known through a questionnaire applied to the owners, and information regarding the tractors was acquired through catalogs available electronically by consulting the brand and model of the tractor. To demonstrate the mechanization index, the separation was carried out into three bands ( 200ha), so that each band included a number of properties suitable for carrying out area and power averages. The results were analyzed using the Microsoft Office Excel application and the sample size, expressed as a minimum number of tractors, was defined by the method bootstrap adapted (Days et al, 2014), which considered the stabilization of variables due to significant increases in sample size.

Regarding brands, it was possible to observe the predominance of Massey Ferguson, New Holland, John Deere and Valtra, respectively (Figure 1). The other brands found, with lower representation, were CBT, Muller, Agrale, Engesa and Case IH, respectively, whose sum of percentages represented 18% of the total evaluated. 

As for the traction system (Figure 2), the use of 4x2 TDA tractors is predominant among the other categories (70,4%). This is correlated to rice farming activities, which generally require great capacity to exert traction, but sometimes with reduced-sized implements, due to relief conditions and operations that cannot be carried out with larger tractors, as in the case of rammed earth construction. 4x4 tractors represented 8,5% and were found on few properties, being used mainly for soil preparation. 4x2 tractors accounted for 21,1%, and have limitations within the main operations, thus being used for secondary activities such as transport, activating static equipment via power take-off and other activities where the use of a tractor with greater capacity is not justified. to exert traction. 

Regarding the average power of tractors (kW tractor^-1) it was observed that this has grown over the last few decades (Figure 3), with the exception of tractors with a range of 15 to 25 years of use. This range includes articulated models with four-wheel drive (4x4), which were the highest-powered tractors manufactured at the time. From tractors over 25 years old to tractors up to five years old, average power increased by 20%. 

The mechanization index averaged 1,70kW/ha, being higher for smaller areas and lower for larger properties (Figure 4). For properties smaller than 200ha, the IM was 2,09kW/ha. Properties between 200 and 600 hectares resulted in an IM of 1,57kW/ha and properties larger than 600ha resulted in an IM of 1,46kW/ha. Schlosser et al (2004) found similar results in the diagnosis carried out on rice crops in the central region of the state, linking the higher rate of mechanization on small properties with greater work capacity and allowing tasks to be carried out in a shorter period of time and with greater care. The fact that large properties have a lower level of mechanization implies greater planning of activities due to the large areas to be prepared. These often use the night shift and have a higher level of onboard technology, enabling greater operational capacity.

As for the operating station, the predominance of tractors with EPC (45%), followed by cabs (38%) and finally those without EPC (17%) can be observed. Schlosser et al (2002), report that 51,7% of the most serious accidents with agricultural tractors are caused by rollovers, in this case, tractors without EPC present an imminent risk to the operator. The cabin offers greater comfort and safety during operations, allowing the operator to experience less physical strain. 

Looking at Figure 6, it can be seen that the majority of tractors were in good external condition (49,3%). Although tractors from different eras were evaluated, some of them received repairs in the body shop, being in regular condition (30,9%) and in poor condition (19,7%).

In conclusion, it can be seen that the average power was 90kW per tractor, with a growing trend in newer tractors. The 4x2 TDA traction system is the most common, due to the characteristics of irrigated rice farming operations. Four brands of tractors predominate on the properties and 50% of the tractors are in good external condition, largely due to the extreme operating conditions to which they are subjected. Other data relating to all tractor systems are being processed for future presentation, expanding the characterization of tractors in this strong agricultural region in the south of the country.

Vilnei de Oliveira Dias, Bruno Pilecco Bisognin, Bruna Flores Batistella, Camila Dalcin, Tiago Gonçalves Lopes, Lamap/Unipampa Alegrete

Article published in issue 161 of Cultivar Máquinas.