The use of the driving strategy SUTB had the lowest consumption, in all load levels and travel speeds, when compared to FT (Figure 3).
From the regression equations presented in Figure 3A, an increase of 1.79 and 2.15 L h-1 is observed for each 10% increase in load levels applied on the tractor, for FT and SUTB, respectively.
The results presented in Table 2 show that, for all combinations, there was a difference between the two driving modes and six load levels, where hourly consumption varied from 10.86 L [h.sup.-1] for SUTB, at 5.16 km h-1, to 28.27 L [h.sup.-1] for FT at 10.48 km [h.sup.-1].
For a tractor operating with a load level of 50% of the maximum drawbar power, at a travel speed of 7.29 km [h.sup.-1], the potential fuel saving is 18.38% (20.24 L [h.sup.-1] with FT as opposed to 16.52 L [h.sup.-1] with SUTB).
Considering the price paid for one liter of mineral diesel, the consumption reduction, and consequently, the cost of tractor work are important to justify the use of the SUTB strategy instead of FT.
For all treatments evaluated, the SUTB strategy was statistically lower than FT regarding specific fuel consumption, determined by a Turkey test at 0.05 significance (Table 2).