Free Co2 Via Soil Respiration

[Homesteader]

I accidently discovered this week that my soil mix creates massive amounts of CO2 when it is cooking. I mixed about 200 gallons of soil mix and decided to put them in the grow room for a few days while I waited for my order from Logic to get in. I was shocked when the next morning, my monitor showed 2500ppm when my room was set for 1250ppm. I never had a problem in the short time that I have owned this equipment, so I turned off the gas and let the room air out and get back to about 700-800ppm. A few hours later, the # was at 1800ppm with no gas on.


I decided to experiment with this and found the ppm climbs significantly higher if I moisten the soil and then drops as it dries. I also found that I can seal the soil in 40 gallon totes and burp them to release about 800ppm+ at 1hr.


Anyone else ever observe this type of soil respiration? I have never heard of it in any discussion and I assumed that my soil was hot and created some CO2 but never expected 2500ppm in a few hours.


Like I said I only discovered this the other day, but my gas has been off all week and my room has stuck around 1000-1500ppm. I assume this is bacterial activity from a lot of sources, but I am assume the majority is from the rice hull and peat decomposing…….any insight….?



Here is a link to my soil mix.

https://www.thcfarmer.com/community/threads/soil-mixes-w-soil-tests.83464/#post-1754440

 

[Paul Simon]

This is the carbon cycle! When plants breathe in CO2 they use it to build structure combined with light energy. As these structures are broken down by microbiology, nutrients are seperated from CO2 and immobilized in the microbes while the energy used to make the now digest compound is released in the form of thermal energy.

Now get a thermal transfer coil to put in your compost pile to extract the heat for hot water or area heating. We are going to try a year around light dep in a Walapini heated with compost.

 

[Homesteader]

Discovered that this was not the case, with the base of my soil alone. Was kind of hoping that EWC and Peat by itself would raise the #s but it didnt seem to be significant. PPM last night was at 800ppm. Opened up a sealed 20 gallon bag of soil mix, and it rose and maxed out at 1700ppm within 30 min. I will continue to seal/unseal bags every other day and open another and see how long this respiration lasts. This seems to provide more than enough. Still haven't had the need to turn the gas back on.

 

[Seamaiden]

Did I hear someone say carbon cycle...?

@Homesteader I am very glad you decided to open this discussion up with the rest of the forum. The whole thing is pretty wild and we're still learning so much.

 

[Homesteader]

PPM was down to 600 last night and the soil was slightly dry. Watered media and PPM climbed back to 1450ppm by this morning. I am now only using the growing media that I have in the room and no longer burping bags or totes. I know this seems unbelievable, but I don't know what to tell you other than its working. I assume that because most people buy premixed soil they don't have the decomposition that mine does. I would love somebody to try out my soil mix and see another point of view on this subject.

edit: all together there is about 100 gallons of soil in pots right now, and that is what is producing the CO2. The other bags and totes are out of the room.

https://www.thcfarmer.com/community/threads/soil-mixes-w-soil-tests.83464/

 

[Homesteader]

CO2 remains steady after two weeks at 1400 to 1500 ppm with no gas and only drops when media begins to need watering. PPM no longer climbs above 1600 ppm either which leads me to believe their is some slowing in decomposition.

 

[Homesteader]

After a few days of getting lower readings and adding a 45 gallon bag of soil to the grow, CO2 was at 3300ppm this morning. Obviously too high, but back down to 1000 after a few minutes of airing out.
A month now of no gas? I was wondering why I used so little gas in the past, figured I was just more sealed than others or smaller plants. Aside from the occasional spike when new soil goes in, this seems like the way once I get it dialed in.

 

[Homesteader]

Finally turned the gas on last night after about a month of free CO2. The levels were reading in the 600ppm range in the days with temps at 82-84 degrees and then would spike during night cycles to about 1500ppm at 78 degerees unless the medium was dried out, which would bring the number down to about 1000ppm. Even though my gas is now turned on, due to the respiration, it will only be needed a few times a day if that.

 

[Bulldog420]

Paul Simon gave a great response.

Homesteader, what you are experiencing people pay money to test for. Check out this info at Logan Labs. Really explains what is going on here.

http://loganlabs.com/doc/respiration_guide-NRCS-Solvita.pdf
http://loganlabs.com/doc/Professional-Soil-Interpretation-Guide.pdf

Thanks again for another great thread.

No idea if that link will work, it's a pdf. If it doesn't, go here.... http://loganlabs.com/customer-tools.html and click on the very bottom right link that says soil respiration and solvita test. Bottom two.

 

[Homesteader]

Awesome links @Bulldog420 ! I have some homework. This sentence here describes why I didn't see the same activity with just peat and microbes.

"The amount of soil respiration is an indicator of nutrients contained in organic matter being converted to forms available to crops (e.g., phosphate as PO4, nitrate-nitrogen as NO3, and sulfate as SO4)."

 

[Homesteader]

This soil was made 4 months ago give or take. 3500ppm-2000ppm first month and ammonia smell from the N breaking down (No bueno for growing). 1800-1200ppm month 2and 3 with earthy smells. Started dropping in flower on last grow and was 1000-800 ppm towards the end.

Reactivated this soil with EM-1 and forest microbes and numbers are back to 1500-900ppm with signs of dropping only when media is drying up. Fish raises the numbers considerably but never above 1500ppm using about 200 gallons of soil.

Attempt a C:N of 50:1 and add microbes moisture and 78 degrees.
brick of coco, 5 gals peat, 5 gals rice hull, 5 gals EWCs and 1-2 cups of soy and bone char.
Magic

"Solvita ® 1-day CO2-C: This result is one of the most important numbers in this soil test procedure. This number in ppm is the amount of CO2-C released in 24 hours from soil microbes after your soil has been dried and rewetted (as occurs naturally in the field). This is a measure of the microbial activity in the soil and is highly related to soil fertility. In most cases, the higher the number, the more fertile the soil.
Microbes exist in soil in great abundance. They are highly adaptable to their environment and their composition, adaptability, and structure are a result of the environment they inhabit. They have adapted to the temperature, moisture levels, soil structure, crop and management inputs, as well as soil nutrient content. In short, they are a product of their environment. If this were not true they most likely would have died out long ago, but they didn’t. Since soil microbes are highly adaptive and are driven by their need to reproduce and by their need for acquiring C, N, and P in a ratio of 100: 10: 1 (C: N: P), it is safe to assume that soil microbes are a dependable indicator of soil health. It is clear that carbon is the driver of the soil nutrient-microbial recycling system. This consistent need sets the stage for a standardized, universal measurement of soil microbial activity. Since most soil microbes take in oxygen and release CO2, we can couple this mechanism to their activity. It follows that soil microbial activity is a response to the level of soil quality/fertility in which they find themselves."

 

[Homesteader]

"Microbial soil respiration and its dependency on carbon inputs, soil temperature and moisture"

 

[Homesteader]

 

[Homesteader]

This video is the best source of information that is available in regards to soil respiration.

 

[Homesteader]

One awesome observation I have made recently IMO is how the production of CO2 is so quickly stopped when temps fall below 78 degrees. I have observed high respiration at 78 degrees and virtually none at 75 degrees. On the wamer end, I see production slowing above 82 degrees but not stopping all the way up to 90. I have yet to go above that temp, but I assume that it would continue to slow until 98 degrees it would stop, but that is just a guess.

 

[Homesteader]

Experimenting with a 2:1 peat moss and Earth Worm Castings mix to see how much CO2 20 gallons will produce. I assume that the mix needs about three days for the fungi to start oxidizing the peat. I may find that I need to add fish, but at this point I don't know.

 

[jumpincactus]

One awesome observation I have made recently IMO is how the production of CO2 is so quickly stopped when temps fall below 78 degrees. I have observed high respiration at 78 degrees and virtually none at 75 degrees. On the wamer end, I see production slowing above 82 degrees but not stopping all the way up to 90. I have yet to go above that temp, but I assume that it would continue to slow until 98 degrees it would stop, but that is just a guess.

Yes this would make sense as the soil carbon cycle does like warmer temps for the process. Here is a small snippet from a study by Raich & Schlesinger and PeterJohn et al 1994

Reference the para titled Elevated Global Temperatures Great thread BTW you are bringing out the soil carbon cycle nerd in me. :) here is the link, Once at the site you can download the full pdf file

https://www.researchgate.net/profil...rbon_Cycle/links/54b165a00cf220c63ccf9d45.pdf

 

[jumpincactus]

Paul Simon gave a great response.

Homesteader, what you are experiencing people pay money to test for. Check out this info at Logan Labs. Really explains what is going on here.

http://loganlabs.com/doc/respiration_guide-NRCS-Solvita.pdf
http://loganlabs.com/doc/Professional-Soil-Interpretation-Guide.pdf

Thanks again for another great thread.

No idea if that link will work, it's a pdf. If it doesn't, go here.... http://loganlabs.com/customer-tools.html and click on the very bottom right link that says soil respiration and solvita test. Bottom two.

Great link @Bulldog420 this is right up my alley.

 

[jumpincactus]

So it would seem that 95 to 104 deg F is the point at which soil respiration becomes limited.

Moisture levels also play a key role as too much moisture can inhibit the process as well.


Inherent factors that impact soil respiration, such as climate, cannot be changed. Inherent soil respiration rates depend on amount and quality of SOM, temperature, moisture, salinity, pH, and aeration. Biological activity of soil organisms varies seasonally, as well as daily. Microbial respiration more than doubles for every 10°C (18°F) soil temperatures rise up to a maximum of 35 to 40°C (95 to 104°F), beyond which soil temperature is too high, limiting plant growth, microbial activity and soil respiration. Soil respiration increases with soil moisture up to the level where pores are filled with too much water limiting oxygen availability which interferes with soil organism’s ability to respire (Figure 2). Ideal soil moisture is near field capacity, or when approximately 60 percent of pore space is filled with water. Respiration declines in dry soils due to the lack of moisture for microbes and other biological activity. As soil water-filled pore space exceeds 80 percent, soil respiration declines to a minimum level and most aerobic microorganisms “switch tracks” and use nitrate (NO3), instead of oxygen, resulting in loss of nitrogen, as nitrogen gases (N2 and nitrogen oxides), emission of potent greenhouse gases, yield reduction, and increased N fertilizer expense.

https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053267.pdf

 

[NightsWatch]

Way to much fucking around to achieve any good c02 for plant growth. you need to factor in lots of stuff alt , barometric pressures , temps etc RH
Why not just buy a bottle and be done with it or put in 1- 2000 liter Vat and start making wine or beer :) in your grow room ..
You here people talk about thermol energy could only imagine how much of a pile one would need to maintain 80 degrees in a house with a shit pile.
Most thermal i have read is there drilling 300 feet into the ground where its more stable in temp variations ,, a shit pile is not going to be stable one bit.
that is just wasted money might as well make a Diy Boiler to heat up what ever

I have made some pretty hot soil mixes and i think the hottest i got it up to was 60 anything hotter were defeating the purpose as micrbioligical life DIE
So your damned if you do and damned if you don't ;)
A well-designed indoor compost system, >10 gallons in volume, will heat up to 40-50°C in two to three days. Soda bottle bioreactors, because they are so small, are more likely to peak at temperatures of 30-40°C. At the other end of the range, commercial or municipal scale compost systems may take three to five days to heat up and reach temperatures of 60-70°C. Compost managers strive to keep the compost below about 65°C because hotter temperatures cause the beneficial microbes to die off. If the pile gets too hot, turning or aerating will help to dissipate the heat.