Soquimich uses a system based on mixed-integer linear programming and expert systems to improve customer service

Determining what fertilizer mix to apply to certain soils is complicated and time consuming. Experts vaguely describe the complex relationships among the influencing parameters, such as fertilizer, soil, weather characteristics, and the previous and target yields. Farmers expect fast and reliable recommendations for fertilizer mixes that will meet their needs at low prices. Like buyers of many products, they take the quality of the products for granted. What differentiates providers is the service they offer their customers. Recognizing this fact, Soquimich, S.A., a fertilizer producer, initiated development of a system that would automatically determine optimal fertilizer blends. We developed a hybrid tool using expert system technology and mixed-integer linear-programming models that increased fertilizer sales. Our initial highly sophisticated preliminary version of the system proved unsatisfactory because farmers could not always provide the necessary input and users did not know how to use and maintain the system. Our final simplified version of the system was successful and is being extended to other regions in Chile and in other countries.