Department of Earth and Environmental Science

Alain F. Plante

Laboratory

Our laboratory is well equipped to provide excellent facilities for research in soil organic biogeochemistry. These laboratory facilities include: an ultrasonic generator and disruptor horn (Branson Sonifier 450D) for physical dispersion of tightly aggregated soil samples, and a high-speed centrifuge (Beckman J2-MI) with high-volume rotor for separation and isolation of soil particle size (silt and clay) and density fractions.

A LICOR LI-7000 infra-red gas analyzer (IRGA) provides the capability for high-precision measurements of CO2 concentrations in gas samples from ambient levels up to 50,000 ppm (depending on injection volume). Two refrigerator-sized incubators are used for laboratory soil incubations at constant-temperature. This capability is used to quantify soil respiration during laboratory incubation experiments as a measure of soil organic matter decomposition by the soil microbial population and its enzymes. An EGM-4 and SRC-1 instrument from PP Systems also provides the same capability for CO2 efflux measurements in the field.

All materials change their physical properties and their chemical characteristics as a function of temperature. Our Netzsch STA409PC Luxx system for simultaneous thermal analyzer (i.e., thermogravimetry and differential scanning calorimetry) provides the capability of measuring mass changes, decomposition behavior, thermal stability, oxidation behavior, etc. of various organic and mineral materials by subjecting samples to temperatures up to 1200°C. Our primary interest in the thermal stability of soil organic matter is as a proxy for biological stability and as means of describing of quality continuum of soil organic matter. To this end, we have coupled a LICOR LI-840a IRGA for measuring CO2 and H20 in the evolved gas during the combustion of soil organic matter during thermal analysis.

Together, these laboratory facilities provide us the means to physically, chemically and biologically fractionate and characterize soil organic matter from a range of soil types to assess its quantity, quality and dynamics.

In addition to our own lab, shared department laboratory space houses a range of traditional soil preparation equipment such as sieves, balances, shakers, grinders, soil and plant drying ovens, muffle furnaces, and adequate storage space for archiving collected soil samples. Departmental facilities also house a range of instrumentation, including: laser diffractometry for particle size analysis, total C and N analyzers (Carlo Erba NA 1500 CN; Costech Instruments Elemental Combustion System), stable isotope ratio mass spectrometry (Thermo Finnigan Delta Plus; Finnigan MAT 252) with various sample preparation units for analysis of 13C, 15N and 18O, mineralogical analysis by x-ray diffraction (Philips XPert Pro XRD Unit), and elemental analysis by inductively coupled plasma analysis (Spectro Genesis).