Predicting the optimal replacement time for farm power and machinery using a computer programme

Abstract

The least-cost machinery selection and replacement was determined in this paper, taking into account fixed, variable and timeliness costs. Replacement models for the medium size diesel-engine tractors (MF 265) were developed and solved using a microcomputer programme written in Dbase. Data obtained from agricultural mechanization schemes in two agricultural zones of Anambra State, Nigeria was used in testing the models. Tractor cumulative use was shown as the major determinant of tractor repair and maintenance costs, and therefore a major factor in the replacement decision. The remaining value of the tractor decayed exponentially with age showing the case is suitable for deterministic replacement modelling. The equivalent average annual operating cost of the tractor under the studied techno-economic situation decreased steadily with tractor age, hit a minimum value of N137,835.98 at year Five, and thereafter increased. The optimum replacement period was therefore shown to be Five years. The equivalent cost followed a 2^nd order polynomial trend. The R² value of 0.9952 and 0.9315 for the tractor’s book value and the equivalent annual operating cost respectively indicated good prediction with the models. Poor book keeping was challenging to successful computerization of agricultural machinery management. It affects timely replacement of machinery and ultimately the cropping operations timeliness, crop yield and profitability of the farm enterprises