Yes, there are some areas that have enough naturally in the soil. It's the same with fertilizers, the middle number can build up in the soil and be more harmful than good. That's one reason a lot of places have gone from triple number (10-10-10 or 20-20-20) fertilizer to the 3-1-2 ratio or close to it (18-6-12 or 16-4-8).
That's why it is important to do a soil test to see what you need to use instead of just adding stuff. You can get a soil test kit at Lowes or Home Depot. Some local agricultural extension offices will do it for free.
