I suggest you contact the people below and have the soil and water tested. My guess is you have high alkalinity due to water/spring going through limestone.

Penn. ----

Agricultural Analytical Services
Penn State University
Tower Rd.
University Park, PA 16802
(814) 863-0841
http://www.aasl.psu.edu
You can purchase a soil sample collection kit at your local Penn State Cooperative Extension County Office�you'll find the list of county offices on the lab's Website or you can call the lab for your county's office. You then mail your sample directly to the lab. The results will be sent to you with a copy to your local extension agent.