Care when using the sugarcane harvester

With legislation that prohibits the burning of sugar cane, mills need to be aware of all the changes that harvesting raw sugar cane requires. The cutting, processing, loading and transportation of raw materials have undergone major changes with the new system and require attention.

Until recently, the predominant harvesting system was semi-mechanized, which involves previously burning the sugar cane. In this system, cutting is done manually and the entire sugarcane is loaded into transport vehicles using machines called loaders. Currently, the mechanized harvesting system has been adopted, which occurs entirely with the use of machines, from cutting the raw material to loading it.

The semi-mechanized system uses a man (cutter) with a sickle/machete or a man (operator) with a cutting machine, after the sugarcane has been previously burned, thus calling it manual cutting. Loading and transportation are mechanized, using a loading machine, which loads the raw material directly onto trucks, which transport the sugarcane to the mill's mill. In this system, single row crop spacing predominates in the country, being 1m in the Northeast region, 1,5 and 1,8m in the Southeast region, however, alternating double spacing is also adopted, with greater predominance in the Southeast region. .

The mechanized system carries out the entire harvest of raw sugarcane, using machines, using the harvester and the tractor and transshipment set. The harvester carries out the cutting and processing (fractionation and cleaning) of the harvested raw material, placing it in the transshipment, which carries out internal loading in the field and overflows the sugarcane into the trucks of the transport system, located in the carriers and, from there, the raw material is taken to the mill's mill. This system has been adopted not only due to its operational and economic viability, which has been proven in studies, but also due to legal, labor and environmental aspects, which induce the adoption of mechanized harvesting in the country's plants. Severo & Cardoso (2009) and the National Biomass Reference Center (2008) express this determination that is contained in the agri-environmental protocol, which provided for the end of sugarcane burning in flat areas by 2014 and slopes by 2017.

To implement the mechanized harvesting system in a plant, according to Benedini & Donzelli (2007), the area must initially be systematized. To do this, it is necessary to level the terrain (altimetry), eliminating impediments such as stones, sticks, anthills, termite mounds and adjusting the plots into geometric shapes, in order to increase the length of the cultivation rows and reduce maneuvers. of headboards. The geometric shape of the plot is considered one of the most relevant factors in systematization, due to its direct influence on increasing field efficiency (EFC) and the operational performance of the mechanized sugarcane harvesting system. However, the rectangular geometric shape and the sinuous strip prove to be more viable, as they provide a greater length of the cultivation rows, Figure 1.

Regarding soil compaction by the mechanized sugarcane harvesting system, according to Benedini & Donzelli (2007), the level of compaction caused has been lower than that of the semi-mechanized system. Among the machines in the mechanized harvesting system, the conveyor harvester has lower compaction compared to the tire harvester, as does transshipment, which uses high-flotation tires and also provides a lower level of compaction when compared to trucks. which are used in loading and transporting sugarcane in the semi-mechanized system.

In the country's mechanized harvesting, single row cultivation spacings of 1m are adopted, common in the Northeast region and, in the Center-South region, of 1,4m and 1,5m, the latter being the most predominant. According to Benedini & Conde (2008), a spacing of 1,5m is adequate, because the harvester does not trample the rows of sugarcane, while a spacing of 1,4m causes trampling and mechanical shock between the transshipment and the harvester elevator. For some time now, mills have also adopted alternating double spacing of 2,4m and 2,5m where sugarcane is harvested with a two-line machine.

Mechanized harvesting has faced difficulties with regard to the agronomic aspect of the loss of raw material in the field, which in many cases does not come only from the harvester, but rather from the cultivated variety. This has been a bottleneck that mills have been facing, due to the lack of varieties that are predominantly upright and suitable (recommended) for the different conditions imposed for mechanized harvesting, such as land topography, cultivation spacing, operating speed and others. However, even with this bottleneck, according to Santos et al (2015), it is certain to be resolved, with precision agriculture, through a productivity monitor for a sugarcane harvester.

In the study carried out by Santos et al (2014) it was proven that mechanized harvesting in double spacing, which uses a two-line machine, presents better operational and economic performance compared to that of a single line, as it travels less and processes more raw material. . However, it increases the operational field capacity (ha/h), operational production (t/h), reduces the total distance traveled in the field, thus reducing the cost of fuel, repair and maintenance. In the end, the two-line harvester provides lower operating costs (R$/ha) and operational production (R$/t).

Therefore, the mechanized harvesting system has also shown great virtue compared to the semi-mechanized one, as the sugarcane straw that is left in the field by the harvester also serves to increase the plant's energy production for the local electricity utilities. Furthermore, as mills already use sugarcane bagasse for energy production, the interest of the sugar and ethanol sector in cogeneration of energy with straw has been aroused even more.

The machines used in the biomass system, which are intended for collecting sugarcane straw for cogeneration, are the rake, the baler and the collecting trailer, all tractor-driven, with only the straw transport trucks being motorized. The raking rake has the purpose of raking, placing in line the straw that was left in the field by the harvester, while the baler has the function of baling the raked straw, in prismatic or cylindrical bales, and the collecting trailer, of forwarding the ready bales for loading onto trucks, which transport them to the plant’s furnace.

However, the mechanized harvesting system is a new era in sugarcane mechanization in relation to the semi-mechanized system, so it will require advanced knowledge of agricultural mechanization from the plants, with the adoption of management methods for planning and managing the machines, as well as of biomass system equipment.

Neisvaldo Barbosa dos Santos, UFPI; Casimiro Dias Gadanha Júnior, Esalq/USP

Article published in issue 159 of Cultivar Máquinas.