Fuente: Wipo "precision farming" A method for in-season macro and micronutrient application based on predicted yield potential and a nutrient response index. The inventive method includes the steps of: determining a nutrient response index for a field; determining the normalized difference vegetation index (NDVI) of an area to fertilize; determining a predicted crop yield for the area; determining an attainable crop yield for the area; determining the nutrient requirement for the area as the difference between the nutrient removal at the attainable yield minus the nutrient removal at the predicted yield, adjusted by the efficiency of nutrient uptake in the particular crop. In one preferred embodiment, processing requirements at the time of application of the nutrient are eased by generating a lookup table of nutrient requirement relative to measured NDVI prior to application of the nutrient.