Soil respiration measurements are used for forecasting, surveying and checking remediation work, for biodegradability measurements of substances (pesticides, fungicides, fertilizers, etc.) and for carrying out toxicity tests. Thanks to specially designed, test-proven vessels, these measurements are made accurate and simple with the OxiTop® Control System. A cost effective alternative compared to conventional methods. Soil respiration measurements can be carried out in 2 different vessel types. For actively respiring soils with strong CO2 development, the MG 1.0 measuring vessel is recommended: its large opening (approx. 100 mm / 3.9 in dia.) easily fits large-volume CO2 absorber vessels for later quantitative CO2 determination.

The determination of the biodegradability should be checked before new chemicals are used for the first time, not only for environmental reasons but to minimize disposal charges. The sample and a blank are stirred at a constant temperature for 28 days in closed bottles. The CO2 produced is removed by means of an absorber, the resulting negative pressure is a measure of the biodegradability. The OxiTop®-C continuous value recording guarantees proper documentation. The measuring bottles and adapters can be autoclaved at 121 °C (249.8 °F).

Anaerobic degradation processes take place in the absence of oxygen. A septum sealed bottle nozzle fills the head space above the sample with inert gas. When anaerobic degradation has taken place, the dissolved CO2 can be driven off and then removed from the head space by means of a CO2 absorber. The resulting pressure difference is proportional to the CO2 concentration; the remaining overpressure is proportional to the methane concentration. The degradation process can be conveniently observed in the “pressure” operating mode.

The use of special measuring bottles with a septum sealed nozzle allows the interference-free addition of substrates and solutions. Pressure alterations could indicate a reduction in oxygen concentration, which could necessitate the addition of oxygen, air, or other gases. It is possible to set a “warning pressure” or a pressure limit so adjustments can be made. The momentary pressure can be stored so the adjustments are fully documented. The recording of these measured values (max. 10 values) permits long-term measurement.