Português

Abstract

The present study aimed to evaluate the visible and invisible losses in mechanized harvesting of sugarcane by using different speeds of the harvester's displacement and rotation of the primary extractor in first-cut cane fields with 7% slope. The trial was conducted in June 2014, at the time of mechanical harvesting in first-crop cane (cane of year), with a productivity estimate of 75 t ha^-1 in the city of Pacaembu, São Paulo. The sugarcane was formed by the variety RB96-5902, with 12 months of age, in spacing of 1.4 meters between rows. Harvesting was performed using a John Deere harvester, model 3520 accompanied by a tractor, coupled to the transhipment. The treatments evaluated correspond to combinations of two speeds of displacement of the harvester (km h^-1) and two speeds of rotation of the primary extractor (rpm), in addition to the speeds usually used by the plant as a control: 3 km h^-1 at 700 rpm , 3 km h^-1 at 1200 rpm, 5 km h^-1 at 950 rpm (control), 6 km h^-1 at 700 rpm and 6 km h^-1 at 1200 rpm. The analyzed variables were the losses in the forms of stumps, bluffs, toletes, pieces, whole reeds, shards and total losses, in t ha^-1 and the total percentage of losses. Significant responses (p ≤ 0.05) were observed for all forms of losses as a function of treatments, except for losses in whole cane and shoot forms. It was concluded that the increase of the rotation of the primary extractor and reduction in the speed of locomotion of the harvester tend to cause an increase in the losses of sugarcane, being, in the conditions of the present study, indicated the speed of 3 km h^-1 with rotation of the primary extractor of 1200 rpm.