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AC (ex2) = Concentration (in mg/L) of nutrient in extract No. 2, where A can be N, P, or K.
%AR (ex2) = % Nutrient released during extraction No. 2, where A can be N, P, or K.
AC (ex3) = Concentration (in mg/L) of nutrient in extraction No. 3, where A can be N, P, or K.
%AR (ex3) = % Nutrient released during extraction No. 3, where A can be N, P, or K.
AC (ex4) = Concentration (in mg/L) of nutrient in extraction No. 4, where A can be N, P, or K.
%AR (ex4) = % Nutrient released in extraction No. 3, where A can be N, P, or K.
A (tr) = % Total release of all extractions, where A can be N, P, or K.
A (ne) = % Controlled release (nutrient not extracted, calculated below), where A can be N, P, or K.
A (cr) = % Controlled release (nutrient released in Extractions 2–4), where A can be N, P, or K. W =
Total unground test portion weight in g.
W = Total unground test portion weight in g.
%TAR = Total nutrient (analyte) released, where A can be N, P, or K.
WIN = Water insoluble nitrogen; 1.02 = dilution factor
correction due to addition of the
preservative = 255 mL/250 mL; V = volume, total, of respective extract, in L.
Calculations
Note: An example calculation can be found in Appendix B of ref. 2
%
( 1)
= �
( 1),
1
1000
� 0.255
0.250 � ,
, ( , 100 )
� 100
%
( 2)
= �
( 2),
1
1000
� 0.255
0.250 � ,
, ( , 100 )
� 100
Candidates for 2016 Method of the Year
215