Traction and Trafficability The transmission of tractor engine power is done in three principal ways: i. ii. iii. Through the driving wheels as traction to produce the drawbar power required for draught implement Through the power take-off shaft and Through the hydraulic system Traction is the force derived from the soil-wheel interface to provide draught. Essentially, there are two components in traction, namely the device and the medium (soil, water, air, etc.). Device Track, wheel, winch In agriculture, we are interested in off-road traction device, just as military and civil engineering. The need for traction study 1. Tractive devices do not operate 100% efficient 2. Operation on agricultural soil differs from normal route. Experiment has shown that tractive efficiency on concrete road can be as high as 75% while onn agricultural soil it is only about 50%. 3. The state of soil after the passage of vehicles is very crucial and important for agricultural production Soil as medium Agricultural soils are an extremely complex engineering material and are non-homogeneous. The study of engineering properties of soils is based on experimental approach rather than analytical approach (exact science). Particle Size Analysis of Soil Below are International Society of Soil Science (ISSS) and British Standard Institution (BSI) classifications. ISS classification Figure BSI classification It is important to know which classification is employed at any time. There is also the United States soil classification. Figure United States soil classification The particle sizes are usually determined by the use of sieves.
