Precision fertilizer rate calculations made easy

Do pH (9.5), high calcium (17,000 ppm Mehlich-3 Ca) soils require higher soil P levels than are recommended in the MLSN guidelines? This question came from a consultant who had observed a growth response after application of monoammoniuim phosphate (MAP 11-55-0) when soil test results suggested levels were above the MLSN minimum guideline of 21 ppm Mehlich-3 (M3) P. The soil test reported 37 lbs P₂O₅/acre with a six-inch sample depth. The MLSN P guideline is 21 ppm (mg/kg) of…