In the subsoiling operation in an Inceptisol with a front wheel drive tractor, worn and new tyres, two engine speeds, two gear ratios and the use or not of the differential lock, were compared. Travel speed, rear wheel slip, theoretical field time, and fuel consumption per hour as well as per worked area were measured. The differential lock did not influence significantly any studied parameter. New tires were superior to worn ones for all parameters. Engine speed of 1800 rpm reduced wheel slip, fuel consumption per hour and per hectare compared with 2000 rpm. Fourth gear reduced the theoretical field time and fuel consumption per hectare compared to third gear.
differential lock; tyre wear; gear ratio; soil tillage
