1. A process for determining the health of crops in a field and for correcting deficiencies in the health of the crops, comprising the steps of: georeferencing aerial photographs of at least a portion of said field, said aerial photographs having a particular spatial resolution; preparing a relative greenness map of the field providing crop status information having spatial resolution equivalent to the spatial resolution of said aerial photographs; converting said relative greenness map to a nitrogen recommendation map having spatial resolution equivalent to the spatial resolution of said photographs; and applying nitrogen to said field according to said nitrogen recommendation map, whereby said nitrogen is applied to said field without loss of spatial information.