Qualidade da operação de preparo do solo em três velocidades de deslocamento

The use of agricultural mechanization allowed for more efficient cultivation practices in crops. We aimed to evaluate the quality of the soil tillage operation with an offset disc harrow at three displacement speeds using the Statistical Process Control (SPC). The speeds were 3, 4 and 5 km h -1 . It´s was used a brandNew Holland tractor, model 7630, with 80 kW (108 CV) engine power, coupled at leveling harrow. The operational field capacity and the effective field yield were evaluated as indicators of soil tillage operation quality. The operational field capacity acquired a stable process at all speeds. The effective field yield gained process instability when worked with 3 km h -1 . The approach of Statistical Process Control in the soil preparation allowed the identification of unstable points in the effective field yield for a speed of 3 km h -1 . The existence of variability in the effective field yield does not compromise the stability of the soil tillage operation with an offset disc harrow at the three speeds. The operational field capacity and the effective field yield show less variability in the speed of 3 km h -1 .