Coupling of Crop Assignment and Vehicle Routing for Harvest Planning in Agriculture

A method for harvest planning based on the coupling of crop assignment with vehicle routing is presented. Given multiple fields (up to hundreds), a path network connecting fields, multiple depots at which a number of harvesters are initially located, the main question addressed is: which crop out of a set of different crops to assign to each field. It must be answered by every farm manager at the beginning of every yearly work-cycle starting with plant seeding and ending with harvesting. Rather than solving a pure assigment problem, we also account for connectivity between fields. In practice, fields are often located distant apart. Traveling costs of machinery and limited harvesting windows demand optimized operation and route planning. The proposed method outputs crop assignment to fields and simultaneously determines an optimized sequence in which to service fields of the same crop during harvest. The described scenario is of particular relevance for larger farms and groups of farms that collaborate and share machinery. We derive integer programming (IP) based exact algorithms. For large numbers of fields, where exact algorithms are not tractable anymore, elements of clustering and the solution of local Traveling Salesman Problems (TSP) are added, thereby rendering the method heuristic, but also large-scale applicable.