This is very important. Farmers with thousands of acres still divide it all into subfields that are around 2500 square meters that they manage separately. They are looking to go smaller than that, which computers allow them to do.
By manage separately the same tractor crosses over each one in a field, but each subsection gets a different amount of fertilizer, seed, and other chemical based on all the data they can get. Sometimes they even have more than one seed/chemical tank so they can apply different amounts of each in one pass.
When you have poor and good soil in the same field (all fields have this to some extent) you want to put the minimum money into the poor areas, while it is worth putting more into the productive areas. (People often ask about building up the bad soils - this is done too, but you can't really change the sand/clay ratio)
