We study an approach for the optimization of spreading performed by centrifugal spreaders in order to minimize environmental effects due to application errors. Faced with a large scale problem, we divide the domain of study into subdomains so that each tramline is individually dealt with. In order to take into account the mechanical limits of the device, some inequality constraints are introduced. After cost function discretization, we use an augmented lagrangian algorithm associated with a L-BFGS technique to solve the problem. Results are presented for parallel and non parallel paths.