Commercial Sugarcane Estate Irrigation System Evaluation Using a Network Flow Model with a Piece-Wise Linear Objective Function

Jonas Stray, a lecturer in the Department of Statistical Science will present the Department of Statistical Science seminar with a talk entitled, "Commercial Sugarcane Estate Irrigation System Evaluation Using a Network Flow Model with a Piece-Wise Linear Objective Function .

Commercial sugarcane farming requires large quantities of water to be supplied to the fields, often by means of a system of pipeslines, canals, dams and a combination of irrigation application devices such as furrows or centre-pivots. The field requirements vary with time of year, rainfall, soil type and depth as well as age of crop, to name a few of the factors at play. Current methods for computing the water requirement, and produce an irrigation schedule, work well under the assumption that sufficient water is available at all times. These methods are based on empirically supported models of water requirements of sugarcane and produce schedules indicating how much water to supply to fields at any given point in time. These methods, however, do not fully account for the fact that the ideal irrigation schedule may not be possible to meet due to irrigation system constraints. Our paper proposes to evaluate a commercial sugarcane farm’s irrigation system by modeling the irrigation process as a water allocation problem. Due to the complex nature of water requirements of sugarcane, non-linearities occur in the underlying model. A piecewise linear approximation is used to handle the non-linearity and combines with a network flow model which is solved in a commercial optimisation software package. A test data set is first used to exercise and evaluate the model performance. To illustrate the practical applicability of the model we run a commercial sized data set of over 500 fields.

Monday, October 5, 2015 - 13:00

Lecture Theatre 3, PD Hahn, Upper Campus UCT