DRAFT AND DRAWBAR POWER EQUIREMENT OF MOLDBOARD PLOW IN A CLAY LOAM SOIL

Draft and drawbar power requirement of a general purpose 3-bottom moldboard plow at four levels of soil moisture content (10-12%, 12-14%, 14-16% and 16-18% d.b.) and three levels of plowing depth (20, 25 and 30 cm) were evaluated and compared. The experimental design was a randomized complete block with a 3x4 factorial. The effect of plowing depth on draft and drawbar power was highly significant. Both total draft and drawbar power increased almost linearly with plowing depth. Also, an increasing trend of specific draft with plowing depth was observed, which was attributed to the higher soil bulk density at lower depths. The effect of soil moisture content was significant only on specific draft in such a way that its maximum value occurred at the moisture content of 10-12% and its minimum at 14-16%. Observation of soil condition following the plowing treatments showed better pulverization at higher moisture contents. An acceptable degree of soil clod size was obtained at the moisture range of 16 to 18% for the clay loam soil tested.