Why test?

Wisconsin has many deposits of limestone that can be ground and used as an agricultural liming material. The purity of the limestone and the degree to which it is crushed determines it’s relative value in reducing soil acidity.

In addition to traditional ground agricultural limestone, there are many other types of materials that are being applied to Wisconsin fields that have value as a liming material. The only way to determine the grade/quality of ground limestone or the comparative effectiveness of alternate or byproduct materials is to test a sample of the material.

Analysis and Reporting

For traditional ground agricultural limestone, the analysis includes both the fineness and purity factors to calculate a neutralizing index. The fineness factor is based on dry sieving and the purity is determined by comparing the sample to pure calcium carbonate.

In most cases, byproduct liming materials cannot be testing using the conventional methodology due to the presence of clumps or aggregates making it impossible to sieve the sample. In these cases, the calcium carbonate equivalency is reported on a dry matter basis along with the percentage of solid material. Additional recommendations on use of this material are provided based on the calcium carbonate equivalency.