Optimizing cropping pattern to maximize water productivity

摘要

Proper water management is becoming a must since shortage started to cause serious problems. The United Nations is stressing on the need to gradually produce more output and/or value per unit of water. The main purpose of this study is to improve water productivity. An optimization model was developed solved by linear programming utilizing the General Algebraic Modeling System to obtain the optimum cropping pattern that maximizes revenue per unit water taking into account crop evapotranspiration, land, market and water availability as constraints. A case study was conducted in Lebanon on an area of 6700 Hectares located in South Bekaa. It was found that the peak water productivity of 1306 LL/m~3 of water occurred at an available irrigation water volume of 26 MCM with a net revenue of $3,383 per hectare and a land use density of 180%, whereas, the peak total net revenue stabilized at 37 MCM with a net revenue of $3,834 per hectare, a water productivity of 1045 LL/m~3 and a land use density of 175%.