Highlights • Soil texture sample taken from field area was silt clay soil. • Parameters determine the draft force of ard plow in silt clay soil were identified. • Parameters used to develop draft force of ard plow were reduced using dimensional analysis. • Parameters using to predict draft force was fitted with measured draft force. • Mathematical model was developed and it can help to reduce draft force and can be input for designing ard plow.

Abstract Due to Ethiopia's rising population, the prediction of a draft force has several crucial in improving tillage performance in smallholder farmland. It helps in proper usage of animal draught; minimizes operator tragedy and full input data for the ard plow designer. This study aimed to develop an effective mathematical model by selecting appropriate soil properties, tool geometries, and tillage operating conditions for estimating the draft force of the ard plow. A mathematical equation was established using dimensional analysis related to PI-Buckingham-pi theorem. The model was verified and validated using the IBM SPSS statistical software. The correlation between draft force between the measured and predicted value of R² was 0.877. The developed model was effective in predicting the draft force success for ard plow as much as 87.70%. No significant difference existed between the measured and predicted values at a 0.05 significance level. The scoring standard of the measured draft and the anticipated draft force is normally distributed with a level of confidence of 99%. Investigation consequence showed a developed mathematical formula for estimating the draft force of ard plow in silt clay soil is effective.