Hello,

I am making an apparatus to measure soil respiration over a 24 hour period for the Haney Soil Health Test and am having some trouble determining what math needs to be done. The test originally used Solvita gel paddles to measure co2 and reports values in CO2-C ppm, however, the creator of the test now recommends using NDIR or IRGA sensors for measuring CO2-C. I have made a product that goes into a mason jar lid and measures in ppm. I am wondering what conversion i need to do to take the raw data from just CO2 in ppm to CO2-C in ppm while accounting for the dimensions of the incubation jar (0.2365-L glass jar) and (i think?) the mass of dry soil that went into the test (40g). I believe this paper (https://soilfertility.osu.edu/sites/soilf/files/imce/Protocols/Respiration%20Protocol%20-%20OSU%20Soil%20Fertility%20Lab%20%28Oct%202019%29.pdf) is on the right track and mostly what I need to do, but they convert into a different value while also using a calibration method that I will not be using. I will be using a blank mason jar measuring the ambient CO2 levels and removing that value from the unknown soil sample CO2 values to correct for background levels. I believe my next step will be to plug the raw CO2 (ppm) values into the ideal gas equation to account for those conditions as shown in the linked paper, but I need to stay in ppm.

This paper is what I am basing most of my protocol on because it is made by the creator of the test that I am trying to run, Dr. Rick Haney (Article Simple and Rapid Laboratory Method for Rewetting Dry Soil fo...

Any suggestions or advice would be appreciated.

Thank you,