Postoptimal linear programming analysis of farm machinery

Linear programming (LP) is a widely used technique for farm machinery selection. Shadow prices from LP models are typically used to identify farm machinery bottlenecks. Shadow prices represent the value of an additional unit of a scarce resource, such as planter hours during a given time period. This shadow price approach can be misleading since a machinery change may affect the usages of other scarce resources, such as tractors and labor. A postoptimality algorithm is presented which improves on the shadow price approach. This algorithm gives detailed information on the effects of a machinery change on all relevant tractor and labor resources. This information is useful for investigating complex machinery interactions. The postoptimality algorithm is illustrated with a case study in Texas.