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Soil Test Conversion: Modified Morgan Extraction Method

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Extraction method: Modified Morgan

Please choose which lab analyzed your sample:

University of Vermont
University of Maine
A & L Laboratories, Inc. (enter ONLY P data. No conversion available for Ca, Mg, and K)

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

  Value      Units
Phosphorus: ppm lbs/acre 
Calcium: 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 Eastern Laboratories Inc. (Mehlich-III P, K, Ca, Mg and Modified Morgan P), A&L Canada Laboratories Inc. (Mehlich-III P, K, Ca, Mg) 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 Universities of Vermont and Maine (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 8/30/2003.

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)

  U. of Vermont - Modified Morgan   Cornell Morgan Equivalents
  P Ca Mg K   P Ca Mg K
  ppm ppm ppm ppm   lbs/acre lbs/acre lbs/acre lbs/acre
min 0 5 8 0 n 232 232 232 232
max 119 8174 574 658 r2 0.92 0.85 0.75 0.67

  U. of Maine - Modified Morgan   Cornell Morgan Equivalents
  P Ca Mg K   P Ca Mg K
  lbs/acre lbs/acre lbs/acre lbs/acre   lbs/acre lbs/acre lbs/acre lbs/acre
min 5 714 63 94 n 228 228 228 228
max 178 15322 1192 1151 r2 0.97 0.99 0.99 0.98

  A & L laboratories, Inc. - Modified Morgan   Cornell Morgan Equivalents
  P   P
  ppm   lbs/acre
min 18 n 235
max 592 r2 0.97