Abstract :
A farm-level mathematical programming model to analyse the economics of alternative tillage and cropping systems for cereal grain and oilseed production is presented. The modelling technique used is discrete stochastic sequential programming (DSSP), which allows for a multistage decision process and stochastic field time constraints. Decision variables are cropping activities, integer tractor and equipment investments and scheduling of tillage and drilling operations. The model is applied to a representative farm with medium to heavy clay soil. Tillage systems assessed are mouldboard plough tillage, chisel plough tillage and direct drilling. The results show that a tillage system characterized by lower capital and labour requirements may be as profitable as a conventional system, despite lower crop yields. Further, the results reveal that there is an interaction between the machinery system and optimal crop mix. A test of the importance of considering field time variability indicates that a deterministic model has a tendency to underestimate optimal machinery sizes.
