Valuation of coupled harvesters

Field evaluation shows losses in corn harvesting carried out by a two-row harvester coupled to an agricultural tractor.

The South Region represents a large share of family farming in Brazil, with corn being heavily cultivated and used within these properties. Small corn producers, in the family farming system, still have a lot of harvesters with one or two rows attached to agricultural tractors, this being a fact justified by the small extensions of the properties and few arable areas. In many situations it ends up not being economically viable to acquire large machines (self-propelled harvesters) for these small farming areas. Therefore, many farmers use attached harvesters, as in addition to being equipment that costs less to purchase and maintain, it also allows them to use the agricultural tractor already present on the property. These machines attached to tractors, as they are low cost, do not feature many technologies present in self-propelled harvesters, which often leads to significant losses during the harvesting process. Among all the management practices carried out during the corn crop cycle, mechanized harvesting is the last stage of the production process, requiring great care when carrying it out, as when carried out without the use of some criteria it can lead to large losses, increasing the cost of production and, consequently, reduction in producer profitability (Bertonha et al, 2012). Inadequate speeds when moving the harvester and grain moisture are factors that help increase the number of grain losses. To reduce the amount of losses in the mechanized harvesting process, it is possible to improve the level of instruction of operators, carry out periodic maintenance of harvesters with efficient settings, choose a correct working speed and the right time to start the harvesting operation (Balastreire , 1987). In Brazil, there is great use and commercialization of coupled corn harvesters and farmers in different regions of the country do not have information about the ideal operating conditions of these machines. Therefore, researchers from the Instituto Federal Catarinense carried out a study with the objective of quantifying losses during the mechanized harvesting of corn with three travel speeds and two degrees of moisture in the corn grains, using a two-row harvester coupled to a tractor. agricultural. The experiment was conducted in the 2015/2016 agricultural years in an area of ​​the Teaching, Research and Production Farm of the Instituto Federal Catarinense (IFC) - Campus Rio do Sul, in Santa Catarina.

Read also

FIELD TESTING

Before installing the project, soil samples were taken in the 0cm-20cm layer, forming a composite sample, which was sent to the soil chemical analysis laboratory in the Alto Vale do Itajaí region of the Agricultural Research and Rural Extension Company of Santa Catarina - Epagri. Fertilization was carried out according to the interpretation of the soil analysis and recommendation for corn cultivation, following the recommendation of the fertilization and liming manual for the states of Rio Grande do Sul and Santa Catarina. Corn was sown in November 2015 and defined with a population of six plants/m² and spaced 0,80m between rows, using the 30F53 Conventional Hybrid from Pioneer Sementes. During the development of the crop, spraying was carried out in accordance with agronomic management recommendations and top dressing was applied as recommended by the interpretation of the soil analysis. When the crop reached physiological maturity, grain samples were collected and grain moisture was constantly measured until the desired moisture levels were reached for field analysis. Mechanized harvesting was carried out using a Jumil JM 380 harvester coupled to the tractor, with an axial flow system, positioned laterally, coupled to the tractor's drawbar and chassis. The harvester consists of a harvesting, feeding, threshing, separation and cleaning system, and it harvests two rows of plants at a time with a total platform opening of 1,6m. The traction and drive of the harvester were carried out by a New Holland tractor, model TM 135 with Auxiliary Front Wheel Drive, with 102kW of power. The experimental design used for data analysis was a factorial design with two factors (three harvester travel speeds versus two degrees of grain moisture) containing five repetitions. The differences in humidity were obtained through harvesting on different dates, with the first harvest being carried out when the grain moisture averaged 26% and the second harvest period was carried out when the humidity was around 21%. Harvesting speeds were 3km/h, 4,5km/h and 6km/h, respectively. The variables used for statistical analysis were the loss of grains that fell when passing through the cutting platform and the grains that fell to the ground after passing through the separation and cleaning system with a track. To quantify losses, the methodology described by Mesquita was used. et al (1998). At the time of harvest, plots 50m long were used, with the first 20m serving to stabilize the grain flow inside the machine and the rest of the plots being used to quantify lost grains. To determine the grain losses through the impact of the cutting platform and internal mechanisms, which together represented the total loss, relative to the harvester, a 2m² frame was used with variable dimensions according to the cutting width of the platform, placed on the transversal direction to the planting of the lines. The loose grains and those contained in cobs found on the ground inside the frame were weighed and the values ​​were transformed into kg/hectare. The collected samples were weighed on an analytical balance and subsequently equalized to the moisture content of both samples collected at different times, so that there was no extrapolation of the results using the moisture value used for the sale of corn grains of 13%. . The data obtained were subjected to analysis of variance using the F test and comparison of means using the Tukey test, at a 5% probability level.

Table 1 contains a summary of the analysis of variance and test of average losses caused by the sum of the platform and threshing mechanisms, generating the total losses caused by the harvester. It is possible to note that there was no significant difference between the three work speeds during harvesting when grain moisture was 21%. However, when grain moisture was at 26%, at the same three speeds, there was a significant effect on the increase in grain losses as the harvesting speed increased.

Young and other researchers already in 1953 found that losses in the field with a harvester coupled to the tractor increased as there was an increase in harvesting speed, and at the time the machines were less technologically advanced, going so far as to recommend that harvesting be carried out with tractors. using first gear to move. It is worth mentioning that the authors Ortiz and Cañavate, in 1993, reported that harvesting speeds of 4km/h generated total losses ranging from 3,5% to 10,5% of production per hectare, and could even double this loss value when the speed increased to close to 7km/h.

Regarding the level of humidity related to harvest losses, it was possible to notice that when the crop had grain moisture close to 21%, the losses were not very significant. However, when the harvest was carried out early, with the moisture content of the corn grains at 26%, the losses of grains fallen to the ground after passing through the harvester's threshing and separation mechanisms were greater than 1,5 bags/ha, mainly in the speed of 6km/h. The results found in this work are similar to those found by Loureiro in 2012, who evaluated the quantitative losses occurring in the mechanized harvesting of corn grown in reduced and conventional spacing, where losses greater than 1,5 bags/ha were observed for losses on the platform and mechanisms internal.

According to Sgarbi (2006), as the grains dry in the field, the performance of the harvester improves, both on the platform and in the internal mechanisms (trail and separation), a fact also pointed out by Portella (2003). However, the longer the crop takes to leave the field, the greater the chances of lodging occurring. Otherwise, when the crop is removed in advance from the field with high moisture levels, the producer needs to take into account the need and availability of drying, the energy spent on drying, the risks of deterioration, in addition to the increase in losses in the mechanisms trail (Quick and Buchele, 1978). In general, the losses of grains fallen to the ground after passing the cutting platform and passing through the internal mechanisms of the harvester were high, and at 26% humidity the losses were higher compared to when it was at 21%, since that, as there was an increase in harvesting speed, there was an increase in grain losses. The average values ​​are represented below.

Dionata Hotz, Fabrício C. Masiero, Ricardo K. Veiga, Adelino Do Amaral, Marlon Goede, IFC - Rio do Sul Campus

Article published in issue 168 of Cultivar Máquinas