A non-linear model is presented which optimizes the lay-out , as well as the design and management of trickle irrigation systems , to achieve maximum net benefit . The model consists of an objective function that maximizes profit at the farm level , subject to appropriate geometric and hydraulic constraints . It can be applied to rectangular shaped fields , with uniform or zero slope . The software used is the Gams-Minos package . The basic inputs are the cropwater-production function , the cost function and cost of system components , and design variables . The main outputs are the annual net benefit and pipe diameters and lengths . To illustrate the capability of the model , a sensitivity analysis of the annual net benefit for a citrus field is evaluated with respect to irrigated area , ground slope , micro-sprinkler discharge and shape of the field . The sensitivity analysis suggests that the greatest benefit is obtained with the smallest microsprinkler discharge , the greatest area , a square field and zero ground slope . The costs of the investment and energy are the components of the objective function that had the greatest ef fect in the 120 situations evaluated .