Methods for analyzing soil, vegetation and sediment samples for total S and handling soil samples for analysis of S constituents were examined. A LECO automated total S analyzer (SC-132) was used for the analysis of vegetation, sediments and soil samples. Results from the LECO analyzer compared favorably with other currently used total S techniques such as alkaline oxidation. Calibrating the instrument on soil or vegetation standards using two combusion accelerators improved accuracy and recovery. The upper 99% confidence interval RSD values for duplicate samples using the LECO analyzer were < 15% for mineral soil, < 8% for forest floor and < 3% for sediment samples. Sample analysis takes < 3 min and provides a direct readout of the total S value. Freeze-drying soil samples caused minor changes (< 15%) in S constituent analyses (Zn-HCl reduction, HI-S and extractable sulfate) when compared to fresh (field moist, refrigerated) samples. Oven-drying at 65°C caused greater changes in soils than freeze-drying, primarily in extractable sulfate.
ASJC Scopus subject areas
- Soil Science