Start

Program screenshot.

The inexpensive, precise, computerized respirometer for measuring soil respiration rate simultaneously in 1 to 96 samples for extended periods of time.

RESPICOND VII measures the evolution of CO₂ by capturing it in KOH. This results in a decrease of the conductance in the hydroxide solution, which is measured with platinum electrodes in each incubation vessel. It is a greatly improved version of the apparatus (Respicond I) described in: Nordgren, A. (1988) Apparatus for the continuous long term monitoring of soil respiration rate in large numbers of samples, Soil Biology & Biochemistry 20, 955-958. RESPICOND VII differs from V by having a highly insulated waterbath partitioned into two halves with 48 sample chambers each. The temperature in each partition can be independently controlled at least between 4 and 30 centigrades.

The Program

Data plot.

Versatile control software (a windows program) monitors each incubation vessel during the experiments.

Plotting and listing functions are accessible at all times during the experiments. You can plot the data as conductance (mS), mg accumulated CO₂ and mg CO₂ per hour, all three of which can be viewed in the listing window together with time. The latest scan for all the 96 vessels can also be viewed in these three ways plus a number of parameters, that enable you to judge the precision of the measurements.

Thanks to modern electronics the precision is very high. Basal respiration rate can be measured for two months with the precision shown in the plot above, without replenishing the hydroxide, . For higher precision a more dilute hydroxide solution would be used, which however needs to be replenished more often.

Precision and frequency of measurements

High resolution plot.

You have a total of 96 sample vessels available to you and you could measure all 96 with good precision every 20 minutes. You can measure 4 samples every minute but those samples will have to respire sufficiently per minute to be interesting.

You can enter a general description of the experiment as well as the treatment of each vessel in the data file. The latter is shown when you plot the results. The data files can easily be converted to forms compatible with your statistics and spreadsheet programs.

Work on this equipment started 1980 and operational equipment has existed since 1983. Much experience has been gained during both hardware and software development, that now is built into the Respicond VII respirometer.