Is variable rate fertilizer application worth the money?

work with your fertilizer man you can take advantage of certain situations..... i bought a small farm several years ago late, like april 1st, got it grid mapped, looking at the maps i figured out the lime map and the phosphorus map were almost identical and the potash, zinc, and sulfur were very close, so we used the potash map and blended in zinc and sulfur in the front box on spreader, and used the phos map and added pel lime in the back to start correcting this farm from year one.