(a) The total neutralizing value of agricultural liming materials, which is the neutralizing value of such materials expressed as calcium carbonate equivalence, shall be determined according to procedures 1.004, 1.005 and 1.006 of the Official Methods of Analysis of the Association of Official Agricultural Chemists, 9th Edition, 1960, pages one and two.

1. (1) The calcium carbonate equivalence of agricultural liming materials derived from magnesium sources shall be determined in accordance to procedure 1.007 (for magnesic limestone) and procedures 1.018, 1.019 and 1.020 (for calcium silicate slags) of the Official Methods of Analysis of the Association of [Official] Agricultural Chemists,9th Edition, pages two, four and five.

2. (2) The calcium carbonate equivalence of agricultural liming materials derived from magnesium sources also may be determined according to procedures of the Association of Official Agricultural Chemists, as outlined in Journals of the Association of Official Agricultural Chemists, as follows:

   1. (i) Volume 45 (1), page 200, February, 1962;
   2. (ii) Volume 46 (1), page 96, February, 1963; and
   3. (iii) Volume 46 (4), pages 611 to 616, August, 1963.

(b)