Most researchers have concentrated their efforts to study the drawbar performance of four-wheel tractors, in view of their popularity in Western and other developed countries. Janane et al. [7] conducted tests in heavy black cracking vertisols
(clay content with 63.8%, moisture content of 13.4% and bulk density of 1.6 g/
cm3) to reduce the fuel consumption of 73.0 kW Massey Ferguson 3080 four-wheel
tractor. They found the maximum tractive efficiency close to 0.9, 0.8 and 0.7 for
stubble, chisel and mouldboard ploughed surfaces, respectively. The dynamic traction ratio of 0.40 or greater was found with near optimum specific fuel consumption
over all tractive surfaces. The specific fuel consumption increased rapidly as the dynamic traction ratio fell below this point. Minimum specific fuel consumption was
found over a range of 10–30% slip