1. Credibility in Soil Testing- Analytical Results

In Illinois, soil testing to help farmers plan line and fertilizer programs are done by cumrnercial testing services. The Agronoiny Department, University of Illinois participates in the State Soil Testing Program in research and coordinating rules. Kecognizing that sources of error in the program may occur in FIELD SAMPLING, ANALYTICAL TESTING, INTERPRETATION OF TEST RESULTS, or FORUMLATION OF RECOMMENDATIONS this paper focuses on ANALYTICAL TESTING. Two quality assurarlce programs in ANALYTlCAL...