Abstract: Methods and products are provided for facilitating application of variable-product agrochemicals, such as fertilizer, to an application area, such as a field. The fertilizer or agrochemical may include a single fertilizer or agrochemical type or a mixture. In one embodiment, a fertilizer-application area is divided into application cells, and a fertilizer product is determined for each cell, based on zones of the application area with a similar characteristic, such as topographic wetness index levels. Based on a determined product for each cell, instructions for controlling an agrochemical applicator are automatically generated.