Tractor Tractive Performance Modelling During Ploughing Operation on a Tropical <i>Alfisol</i>: An R Software Packages Approach

Abstract

Modern agriculture relies heavily on tractor applications for various operations. Field performance output from this vital machinery influences the overall production process and system efficiency. Tractor tractive performance modelling involves complex analyzes using terramechanics techniques. This study investigated the application of R software packages to model tractor tractive performance during ploughing operations on a tropical alfisol. The research farm at the National Centre for Agricultural Mechanization (NCAM) was used for the field experiment. The experimental design was a nested-factorial under a Randomized Complete Block Design having three replications. The input factors were tractor power size, T, (60, 65 and 70 hp); tyre inflation pressure, P, (83, 124 and 165 kPa); implement configuration, I, (2 and 3 bottoms disc plough); and operational speed, S, (6.31, 7.90, 9.47, 11.05, and 12.63 km/h). Standard procedures were followed to obtain the measured parameters which were statistically analyzed using the R software package. Correlation analysis and analysis of variance (ANOVA) of the measured parameters at 5% significance level were established. Multiple linear regression was used to develop the model which was validated using the 10-fold cross-validation method. The results obtained show a positive correlation of the measured variables with towing force except for the shear stress and cone index. Input factors and their interactions have a significant effect on tractive performance except for T*S, I*S, P*T*I, P*T*S, and T*I*S. The final developed model has seven variables for predicting towing force with a 6.5 percentage error and an average of 0.4735 cross validation root mean square error. The model quality of fit achieved an R2Adj = 0.8754 which satisfactorily described the response variable.