Salim Almaliki - Department of Agricultural Machinery, University of Basrah, Basrah, Iraq
Majed Salih Himoud - Department of Agricultural Machinery, University of Basrah, Basrah, Iraq
Sadiq Jabar Muhsin - Department of Agricultural Machinery, University of Basrah, Basrah, Iraq

Development of models for prediction draft requirements of disk plough contribute in improving their performance in the field. In this study, a mathematical models was developed to predict draft force requirements of disk plough under various field conditions. Field experiments were carried out at two levels of moisture content (8 and 21) %, two levels of cone index (550 and 980) kPa, three levels of tillage depth (15, 20 and 25) cm and three levels of forward speed (0.54, 0.83 and 1.54) m/sec in a silty clay soil. A stepwise regression algorithm was utilized to extract models and to analyze results by using Design Expert software. Results showed inconsiderable variation between the predicted and experimental values confirmed the thoroughness of this model in prognostication for draft force requirements of disk plough. The mathematical models analysis of variance demonstrated that all parameters had significant effect on draft force of disk plough. The draft force of disk plough increased by (11, 19, 46 and 116) % with increasing moisture content, cone index, forward speed and tillage depth, respectively. The interaction between forward speed and tillage depth had the most effect on draft force of disk plough.

Disk plough, Stepwise Regression Algorithm, Draft force, Design Expert software