The PL-300 is a field measuring device for determining the air conductivity/air permeability of soils. This value characterizes the water-free pore space and thus the soil aeration—a decisive parameter for soil fertility and workability, among other things.

Functionality

A defined air flow is generated using a measurement chamber in the soil volume investigated. The rate of flow is determined from the drop in pressure through a calibrated two stage measurement throttle in the PL instrument. The pressure difference above the soil volume is recorded by a further pressure sensor and supplies the pressure gradient of this flow. The pneumatic conductivity is calculated from these test parameters using the DARCY equation and shown in the instrument display.

The air-permeable pore space is a function of the water content in the soil. For this reason, the PL-300 has connections for an electronic soil tensiometer and a moisture probe, allowing suction tension and/or soil moisture to be measured in parallel. The data of all connected sensors as well as the calibration data of the measurement chambers and a marking of the measurement point are saved and managed by a microcomputer within the instrument. Its compact and tough design make the PL-300 a practical and portable field measurement instrument.

Measurement chamber

In accordance with the requirements of the location, different measurement chambers are available:

• PL-300 measurement chamber for homogenous flow according to dArCY with integrated pressure probe
• PL-300 surface measurement chamber for inhomogeneous flow in undisturbed soil volume
• PL-300 soil sample ring adapter for the measurement of soil sample rings

Why do we measure air permeability in soils?:

• Soil aeration in agriculture: Importance for soil microbiology, root penetration, fertility and yield.
• Evaluation of soil compaction and the resulting loss of soil functions: Soil is considered healthy when approximately 50 % of the pore space is filled with air (Lal & Shukla, 2004).
• Soil hydrologic properties: influence on the infiltration rate, soil drainage and the potential for erosion.
• Environmental monitoring and remediation: planning remediation measures and assessing risks associated with soil contamination.
• construction industry: Informed decisions on soil stability and drainage to avoid subsidence and other structural problems
• Investigation of the influence of bioturbation on the covering of landfills or other contaminated materials.

• 1 x Device case with quick guide in the lid
• 1 x Interface cable
• 1 x Charger with plug
• 1 x Measuring chamber