A non-linear model for farm optimization with adequate and limited water supplies: Application to the South-east Anatolian Project (GAP) Region

This paper develops a non-linear optimization model for the determination of optimum cropping pattern, water amount and farm income under adequate and limited water supply conditions. The objective function of the model is based on crop water-benefit functions. The model is solved using Ms Excel Solver package for conditions existing in South-east Anatolian Region of Turkey. The model gives the optimal distribution of crop areas, irrigation water needs of crops and total profit for the farm under adequate and limited water supplies. The problem was also solved by a linear programming (LP) model, in order to indicate the difference between non-linear programming (NLP) and linear programming models. After the examination of NLP and LP model solutions, it can be seen that, the NLP model can give higher farm income values than the LP model under deficit irrigation conditions. Also, in some capacity levels, with the NLP model, instead of two different irrigation volume applications for one crop, the best irrigation volume ratio has been calculated.