Location: Soil Dynamics ResearchTitle: Simple, simultaneous gravimetric determination of calcite and dolomite in calcareous soils
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2017
Publication Date: 1/4/2018
Publication URL: https://handle.nal.usda.gov/10113/6579859
Citation: Rodriguez, J.B. 2018. Simple, simultaneous gravimetric determination of calcite and dolomite in calcareous soils. Soil Science Society of America Journal. 81:1615-1620.
Interpretive Summary: The carbonate meter (CM) gravimetric technique was modified to simultaneously separate calcite and dolomite in calcareous soils. The new procedure, the modified carbonate meter (MCM) gravimetric technique, can be readily adopted in most soil testing laboratories. The MCM technique was tested using 81 calcite-dolomite-soil mixtures prepared in the laboratory with pure calcite, dolomite and non-calcareous sandy soil. Linear regressions, correlations coefficients, precision and recovery with this technique were excellent. In addition 12 USA calcareous soils were selected to validate the modified method. Furthermore, several calcareous soils from various states, were analyzed with the MCM method and identified soils from Texas, Kansas, Minnesota and Alaska as calcitic, soils from Iowa as calcitic-dolomitic, and soils from Wisconsin as dolomitic. The MCM technique was shown to effectively and inexpensively separated calcite and dolomite in calcareous soils, and could be used for routine analysis of soil.
Technical Abstract: Literature pertaining to determination of calcite and dolomite is not modern and describes slow methods that require expensive specialized apparatus. The objective of this paper was to describe a new method that requires no specialized equipment. Linear regressions and correlation coefficients for calcite and dolomite in calcite-dolomite-soil mixtures, with the modified carbonate meter (MCM) calcite and dolomite results were excellent. Precision for calcite was <5% in 92.6% of samples, precision for dolomite was <10% in 98.8% of samples. Recovery for calcite was 100 + 10% in 86.4% of samples, and recovery for dolomite was 100 + 10% in 97.5 % of samples. The MCM technique efficiently separated calcite and dolomite in calcareous soils. This procedure is recommended for routine analysis of calcite and dolomite concentrations up to 450 g kg-1. The MCM is easy to follow, inexpensive, and results in good precision and recovery.