A mathematical programming model for improvement planning in a semi-subsistence farm

In some semi-subsistence agriculture systems, long fallows have traditionally been used to maintain soil fertility, but fallow periods are often shortened because of increased pressure on land, resulting in reduced crop yields. In such cases crop yields can often be increased by adopting agricultural methods based on the use of new crop varieties, fertilisers and herbicides. These improved cultivation techniques must be introduced over a number of years, but the transition process has received little attention in evaluating improvement of semi-subsistence cultivation systems. In this paper a mathematical programming approach is developed for planning the introduction of improved cultivation systems in a semi-subsistence farm in northern Chiapas, Mexico. This new approach first uses a linear programming model to determine capital dependent steady state cultivation policies. Results from this steady model are then incorporated into a multiperiod mixed integer programming model for determining steady state policy and the associated improvement plan.