Integrated versus hierarchical approach for zone delineation and crop planning under uncertainty

This paper considers the problem of zone delineation management and crop planning. The problem consists of selecting which crops to plant in different management zones in order to minimize the total costs subjected to a given demand requirement. From a hierarchical point of view, the process starts by generating a partition of an agricultural field into homogeneous management zones, according to a given soil property. Then, the best crop rotation must be assigned to each management zone, applying agronomic practices in a site-specific manner in each zone. This hierarchical approach establishes two decision making levels of planning. At each level, a two-stage stochastic optimization model is proposed, representing the uncertain behavior of a soil property and crop yields by using a finite set of scenarios. Next, we combined them into a new two-stage stochastic program, solving an integrated approach by simultaneously determining an optimal zoning and allocation. Results from a set of evaluated instances showed the relevance of the proposed methodology and the benefits of the hierarchical approach over the integrated one.