Skip to main content

Soil Test Conversion: Mehlich-III Extraction Method

Back to Conversion Tools

Please choose which lab analyzed your sample:

Brookside Laboratories, Inc.
Spectrum Analytic, Inc.
A & L Eastern Laboratories, Inc.
A & L Canada Laboratories, Inc.
University of New Hampshire

Please enter data for conversion [equation input ranges are located at the bottom of this page]:

  Value       Units
soil pH:
Phosphorus: ppm lbs/acre 
Calcium: ppm lbs/acre 
Aluminum: ppm lbs/acre 
Magnesium: ppm lbs/acre 
Potassium: ppm lbs/acre 

 
[ note: Please reset the form between data sets to ensure accurate calculations. ]
Cornell Morgan equivalent in lbs P/acre: P
Cornell Morgan equivalent in lbs Ca/acre: Ca
Cornell Morgan equivalent in lbs Mg/acre: Mg
Cornell Morgan equivalent in lbs K/acre: K


Warning and disclaimer: This program converts soil test results from Brookside Laboratories Inc. (Mehlich-III P, K, Ca, Mg), Spectrum Analytic Inc. (Mehlich-III P, K, Ca, and Mg and Morgan P, K, Ca, and Mg), A&L Laboratories Inc. (Mehlich-III P, K, Ca, Mg and Modified Morgan P), A&L Canada Laboratories, Inc., and the soil testing laboratories from the University of New Hampshire (Mehlich-III P, K, Ca and Mg), University of Massachusetts (Morgan P, K, Ca, and Mg) and the University of Vermont (Modified Morgan P, K, Ca, Mg) to Cornell University Morgan Equivalents. Phosphorus conversions from Mehlich-III data require measured values for soil pH, Mehlich-III P, Ca, and Al. For each test, the range of valid input data is given by a minimum value (min) and a maximum value (max). Also given are the correlation coefficients (r2) for each of the conversion models. The larger the (r2), the more reliable the conversion. Models were derived using New York soils. There is uncertainty involved with each of the conversions. The user assumes all risk. For questions, contact Q.M. Ketterings (qmk2@cornell.edu). Last updated 11/3/2002.


Input ranges and correlation coefficients

min = minimum input value
max = maximum input value

n = number of samples on which equation is based
r2 = correlation coefficient (larger = more reliable)

  Brookside - Mehlich-III   Cornell Morgan Equivalents
  P Al pH Ca Mg K   P K Mg Ca
  ppm ppm   ppm ppm ppm   lbs/acre lbs/acre lbs/acre lbs/acre
min 17 380 4.6 473 67 42 n 235 235 235 235
max 575 1576 7.8 6025 507 468 r2 0.88 0.94 0.94 0.92

  A & L Eastern Laboratories - Mehlich-III   Cornell Morgan Equivalents
  P Al pH Ca Mg K   P K Mg Ca
  ppm ppm   ppm ppm ppm   lbs/acre lbs/acre lbs/acre lbs/acre
min 20 453 4.3 526 71 33 n 232 232 232 232
max 581 1560 7.5 6100 560 504 r2 0.90 0.96 0.95 0.93

  A & L Canada Laboratories - Mehlich-III   Cornell Morgan Equivalents
  P Al pH Ca Mg K   P K Mg Ca
  ppm ppm   ppm ppm ppm   lbs/acre lbs/acre lbs/acre lbs/acre
min 20 423 4.3 433 66 28 n 228 228 228 228
max 559 1443 7.3 5558 493 487 r2 0.89 0.95 0.97 0.93

  Spectrum Analytic, Inc. - Mehlich-III   Cornell Morgan Equivalents
  P Al pH Ca Mg K   P K Mg Ca
  lbs/acre ppm   lbs/acre lbs/acre lbs/acre   lbs/acre lbs/acre lbs/acre lbs/acre
min 21 380 4.4 807 124 36 n 235 235 235 235
max 858 1576 7.5 9218 1002 1093 r2 0.88 0.93 0.95 0.93

  U. of New Hampshire - Mehlich-III   Cornell Morgan Equivalents
  P Al pH Ca Mg K   P K Mg Ca
  ppm ppm   ppm ppm ppm   lbs/acre lbs/acre lbs/acre lbs/acre
min 15 340 4.4 762 89 43 n 232 232 232 232
max 561 1819 7.4 7805 660 716 r2 0.90 0.93 0.94 0.93