Influência da lastragem e da velocidade de trabalho na qualidade de operação de uma grade intermediária

Abstract

Intermediate disc harrows have significant use by farmers, however, unsatisfactory operating results have been observed, such as irregular cutting. The present work aimed to evaluate the addition of ballast on a disc harrow in the transversal cut uniformity, such as the influence of the speed factor on the operational performance from the variables of average depth, soil disturbed area, soil heaved area, blistering level, operational specific resistance and effective field capacity. The tests were conducted at the Universidade Federal de Mato Grosso, in the city of Sinop - MT. The soil was characterized as a dystrophic Yellow Red Latosol medium textured with 15.34% water content and presented remains of rice culture. The experiment was arranged in blocks under the 4x2 factorial scheme, being 4 speeds and 2 weight (with and without ballast). The theoretical speeds were 2,5 km h-1, 4,5 km h-1, 7,0 km h-1and 8,0 km h-1. The plots were 4 m x 10 m. A profilometer of metal rods was used to obtain the profiles mobilized and the average depth. The results showed that the ballast addition did not provide cut uniformity for the intermediate disc harrow and the speed factor did not present significant statistical interaction for the mean depth variable, as well as elevated area, mobilized area, blistering and draft. Increasing the operating speed provided gain in operational specific resistance and effective field capacity.