Development and evaluation of a draft force calculator for moldboard plow using the laws of classical mechanics

The moldboard plow is the most common primary tillage implement in the world; therefore, it is valuable to consider this plow from an engineering viewpoint. Since the required draft force and power are among the most important engineering specifications of a moldboard plow, in this paper, a model was developed to calculate them. In this model, the effect of soil cutting, soil displacement, and soil-metal friction on the plow specific draft was considered. Soil parameters, plow parameters, and working condition parameters were considered as the model inputs. To simplify the required calculations, the derived equations were entered in the Excel software, and the finalized spreadsheet was utilized as the moldboard plow draft force and power calculator. To verify the model, comparison of the model outputs with the corresponding results of other studies was carried out. Furthermore, the output of the model and the measured draft force of plowing on a silty clay loam soil was compared. According to the results of this study, the developed model produced acceptable specific draft forces that were within the overall range of the moldboard plow specific draft. Furthermore, draft force and power requirements of a three-bottom moldboard plow working on a silty clay loam soil with the forward velocity of 7 km h−1 were 17.9 kN, and 34.8 kW, respectively, that were about 8% higher than the results obtained by the developed model (16.64 kN, and 32.28 kW). Therefore, the developed model can be used to calculate the draft force and power of the moldboard plow with reasonable accuracy.