DIE ONTWIKKELING VAN 'N MODEL VIR DIE ONDERSTEUNING VAN BOERE BY DIE NEEM VAN VERVANGINGSINVESTERINGSBESLUITE

Abstract

The average age of tractors in use in the RSA have increased considerably the past couple of years and quite a number of tractors arc already too old for effective functioning. The factors that farmers do take into account when they consider tractor replacement are analysed and compared with factors that determine optimality of tractor replacement. Although farmers have become reluctant to replace tractors, when they do consider replacement, the most relevant factors are considered. Various models are available for replacement decisions of which two are especially suitable for the development of decision support systems namely multiperiod integer programming and uniform cost models. An interactive representation of the uniform cost model is given. Although this user-specific model is developed for advice to individual farmers an average tractor replacement age of 10 years was obtained in a nonnative study. This replacement age is higher than the age normally obtained with traditional accounting procedures and can be ascribed to the inclusion of the so called “challenger” in the uniform cost model.

Samevatting

Trekkerouderdomme neem steeds toe en tans is verskeie trekkers in die RSA al te oud om doeltreffend te funksioneer. In die referaal is die faktore wat boere oorweeg by die neem van vervangingsbesluite bepaal en vergelyk met die faktore wat die optimaliteit van 'n vervangingsbesluit beïnvloed. Dit is gevind dat boere traag raak om trekkers te vervang en dat boere dei indien die vervanging van trekkers oorwveeg word, die belangrikste faktore in ag neem. Verskeie modelle is beskikbaar vir die neem van 'n vervangingsbesluit en veral twee tipes blyk geskik te wees vir die ontwikkeling van 'n besluitondersteuningsvervangingsinvesteringsmodel, naamlik die meerpericde integerprogrammeringsmodel en die uniforme jaarlikse koste model. 'n Interaktiewe weergawe van laasgenoemde model is bespreek. Die model is geskik om te gebruik waar produsente van advies met betrekking tot trekkervervanging bedien moet word. In 'n normatiewe studie is gevind dat vervangingsouderdomme van ongeveer 10 jaar verkry word. Die verhoogde ouderdom wat in teenstelling met die tradisionele berekeningsmetodes verkry is, kan aan die insluiting van die waarde van die “uitdager” in die berekening toegeskryf word.