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Soil Physics Sub-Cluster Laboratory

The Soil Physical Sub-Cluster Laboratory provides support to the research faculty, staff, and graduate students of The Pennsylvania State University in the areas of soil physics, pedology, and hydropedology. Available laboratory procedures and equipment include but are not limited to soil:

  • Hydraulic Conductivities: Saturated and/or unsaturated hydraulic conductivity/diffusivity by tension infiltrometer, constant and falling head method.
  • Infiltration rate by single- and double-ring infiltrometers, and rainfall simulators
  • Vadose-zone water-flux measurements by passive-wick water fluxmeters (pan (zero-tension) and wick (fixed tension) lysimeters
  • Water potential measurements by tensiometry, thermocouple psychrometry, piezometry, electrical conduction (generically Buoyucous blocks), and heat dissipation.
  • Moisture retention curve or water release characteristic curve, available water capacities, wilting point, air capacity using pressure plate apparatus.
  • Volumetric water content - volume of water per unit volume of soil by time-domain reflectometry method and capacitance sensors (FDR) and heat-pulse method.
  • Gravimetric water content - mass of water per unit mass of dry soil using oven with 100–110 °C temperature control.
  • Bulk density - the ratio of the mass of the solid phase of the soil (i.e., dried soil) to its total volume (solid and pore volumes together) by core method and clod method in which a known volume of undisturbed soil sample is dried and weighed (gravimetric method).
  • Particle density - the ratio of the solid phase mass to the volume of the solid phase of the soil (measure of the mass per unit volume of the soil solids only) using water pycnometer method.
  • Soil compaction by penetrometer resistance.
  • Particle size analysis (Sand/Silt/Clay, Stones) using pipette and/or hydrometer apparatus and sieves.
  • Aggregate stability - ability of soil aggregates to resist disruption when outside forces (usually associated with water) are applied is determined by repeated agitation of the aggregates in distilled water.
  • Liquid limit (LL) - the moisture content between the plastic and liquid states using ASSHTO T 89 liquid limit apparatus.
  • Plastic limit (PL) - the moisture content at the boundary between semi-solid and plastic states using ASSHTO T 90 plastic limit apparatus.
  • Plasticity index (PI) - the difference between the plastic and liquid limits. It indicates the size of the range over which the material acts as a plastic — capable of being deformed under stress, but maintaining its form when unstressed.
  • Temperature, heat capacity, thermal conductivity, and thermal diffusivity using standard thermometers, thermocouples (soil temperature), soil heat flow probes (surface soil heat flow), thermistors (soil temperatures profiles).
  • Calibration of a wide range of soil monitoring instruments.