Drained peatland GHG emissions source

[JohnGalway]

I'm looking for specific information on GHG's emitted by drained peatlands. Namely, if a piece of peatland is, or has been in the past, drained where on the site do the emissions come from exactly.

Are they mostly coming from open drains/ditches, and/or is it a result of general effect of the lowering of the water table meaning there would be an emitting blanket across that site?

Thinking carbon dioxide, nitrous oxide, methane and whatever else there is.

Hard info appreciated please

 

[Spencer]

For what purpose?

 

[JohnGalway]

For what purpose?

For nefarious purposes. I'm working on something for which I need this information to prove or disprove a theory.

 

[Exfarmer]

The biggest danger is that as the peat dries out, two things happen. The acidity drops which is a natural preservative. Then the peat oxidises releasing carbon dioxide.
methane emissions are caused by the natural breakdown of plant matter in the wet bog, so should cease when it is drained

 

[Exfarmer]

Should have said, the oxidation will be slowed possibly to zero , if the peat is covered by grass and arable cultivation will speed it up dramatically

 

[toquark]

Peat is just uncomposted vegetation, mainly sphagnum moss held in a perpetual state of preservation by anaerobic conditions. Once it’s drained, the ph can rise a bit, but crucially, it allows gaseous oxygen to enter the system and decomposition can begin. As bacteria begin the process of vegetation decomposition, they release co2.

Literally thousands of years worth of carbon storage can be released in a few years with peat drainage.

 

[Exfarmer]

Draining peat land is also the only time when it is proven that drains actually cause flooding. And this was shown on work draining Irish peat bog

 

[JohnGalway]

Hold on...

This is going directions that, while interesting, are getting away from the specific purpose of the thread.

What I'm looking for is, if we're standing on a parcel of land, a field, however one wishes to describe it, where in that field or parcel of land are the emissions coming from.

My own thinking (based on not much) is that there are some coming from the open drains and some coming up through the land itself. BUT I am looking for proper evidence, mapping, measurements, case studies etc. So more specific to localised locations rather than the general terms of this is what happens if..... scenario.

The biggest danger is that as the peat dries out, two things happen. The acidity drops which is a natural preservative. Then the peat oxidises releasing carbon dioxide.
methane emissions are caused by the natural breakdown of plant matter in the wet bog, so should cease when it is drained

This could be helpful in general to what I have in mind, would you have a source on it?

 

[toquark]

The emissions come from the land which is drying out, so anywhere affected by the drainage, on peat flows, it can be hundreds or thousands of acres, depending on the intensity of the drainage.

There is loads of research on the topic to back this up. Its not a controversial viewpoint, its widely accepted. Locally to us the Crichton carbon centre have some research projects ongoing, but I'd just google the topic and I'm sure you wont be long in finding peer reviewed papers on the subject.

 

[JohnGalway]

The emissions come from the land which is drying out, so anywhere affected by the drainage, on peat flows, it can be hundreds or thousands of acres, depending on the intensity of the drainage.

There is loads of research on the topic to back this up. Its not a controversial viewpoint, its widely accepted. Locally to us the Crichton carbon centre have some research projects ongoing, but I'd just google the topic and I'm sure you wont be long in finding peer reviewed papers on the subject.

I'm not attempting to disprove that drained peat is a source of emissions. I'm attempting to form an alternative to "rewetting", which is constantly pushed at "the" solution. While it will do as it says on the tin, it also finishes that piece of land, and possibly neighbouring land, in terms of suitability for grazing. I believe there is another solution, which allows for the emissions to be sequestered, and grazing to continue but with modified management.

 

[Top Tip.]

I'm not attempting to disprove that drained peat is a source of emissions. I'm attempting to form an alternative to "rewetting", which is constantly pushed at "the" solution. While it will do as it says on the tin, it also finishes that piece of land, and possibly neighbouring land, in terms of suitability for grazing. I believe there is another solution, which allows for the emissions to be sequestered, and grazing to continue but with modified management.

I really would doubt that you will get any peer reviewed scientific evidence that says in a quantifiable manner how much co2 is released by peat land either by wetting it or drying it. There is plenty conjecture and hypothesis but hard facts are just about impossible to find. I’ve been around peatland most of my life and I’ve never seen any evidence of gases being released when it is drying although I have seen and smelt plenty evidence of gaseous emissions when it is wetting.

 

[JohnGalway]

I really would doubt that you will get any peer reviewed scientific evidence that says in a quantifiable manner how much co2 is released by peat land either by wetting it or drying it. There is plenty conjecture and hypothesis but hard facts are just about impossible to find. I’ve been around peatland most of my life and I’ve never seen any evidence of gases being released when it is drying although I have seen and smelt plenty evidence of gaseous emissions when it is wetting.

There's a lot of peat where I'm from. What I understand is drainage lowers the water table (duh), this allows more oxygen into the soil, which changes the conditions within the soil and allows the previously preserved plant matter be consumed by soil life, which couldn't do so previously due to the absence of oxygen. Our CO2 comes from (I'm not an expert but I have some knowledge) bacteria being unable to use all of these newly available food resources (the formerly preserved plant material), so they blow off the excess in the form of CO2. CO2 wouldn't have a smell.

My understanding suggests you're correct that gasses are produced from wetting also. I think methane and nitrous oxide, these do smell.

There are, for example, and I'm not sure how high up they are in terms of being peer reviewed, documents out there from pan European sources (Universities) quantifying that drained peatland used as grassland releases "up to" 20 tons of CO2 equivalents per hectare per year, and if used for tillage that figure rises to "up to" 30 tons.

I am hopeful that there is a solution where I can farm away, albeit in a modified manner, while leaving drains open, and sequester the gasses at the same time. A healthy biodiversity can also be maintained, but in a modified environment. I have reached out to some people smarter than myself (wouldn't be hard) to clarify if what I think (based on other peoples work) is correct or whether I've missed something important.

I understand rewetting, but I object to it being pushed by both some policy makers and their backers, as the only solution to this issue. It will leave some farmers with no actual job on that piece of land in the sense that we're used to, nor much other value if historical treatment is taken into account.

 

[Ffermer Bach]

There's a lot of peat where I'm from. What I understand is drainage lowers the water table (duh), this allows more oxygen into the soil, which changes the conditions within the soil and allows the previously preserved plant matter be consumed by soil life, which couldn't do so previously due to the absence of oxygen. Our CO2 comes from (I'm not an expert but I have some knowledge) bacteria being unable to use all of these newly available food resources (the formerly preserved plant material), so they blow off the excess in the form of CO2. CO2 wouldn't have a smell.

My understanding suggests you're correct that gasses are produced from wetting also. I think methane and nitrous oxide, these do smell.

There are, for example, and I'm not sure how high up they are in terms of being peer reviewed, documents out there from pan European sources (Universities) quantifying that drained peatland used as grassland releases "up to" 20 tons of CO2 equivalents per hectare per year, and if used for tillage that figure rises to "up to" 30 tons.

I am hopeful that there is a solution where I can farm away, albeit in a modified manner, while leaving drains open, and sequester the gasses at the same time. A healthy biodiversity can also be maintained, but in a modified environment. I have reached out to some people smarter than myself (wouldn't be hard) to clarify if what I think (based on other peoples work) is correct or whether I've missed something important.

I understand rewetting, but I object to it being pushed by both some policy makers and their backers, as the only solution to this issue. It will leave some farmers with no actual job on that piece of land in the sense that we're used to, nor much other value if historical treatment is taken into account.

Not answering your question, but sort of related, I think when we put Nitrogen fertliser on, the bacteria in the soil need Nitrogen and Carbon to grow, with an excess of N they are looking for C, which they find in the soil Carbon. This is why putting bagged Nitrogen on a field causes the lowering of the soil organic matter. Are there any soil scientists who could tell me if I am right on this?

 

[toquark]

I really would doubt that you will get any peer reviewed scientific evidence that says in a quantifiable manner how much co2 is released by peat land either by wetting it or drying it. There is plenty conjecture and hypothesis but hard facts are just about impossible to find. I’ve been around peatland most of my life and I’ve never seen any evidence of gases being released when it is drying although I have seen and smelt plenty evidence of gaseous emissions when it is wetting.

The forestry industry has done loads of research on the subject. It’s what informed the decision to ban planting trees on deep peat. Check out forest research for actual papers but there are plenty out there.

To try and answer the OP, I think it’s a difficult circle to square to be honest. I did see once in N Ireland some deep peat growing good grass once. The owner said he just threw lime at it now and again, no fertiliser and no drains other than the standard ditch along the field boundary. No idea how that translated to carbon emissions etc, it was just quite an interesting field!

 

[JohnGalway]

The forestry industry has done loads of research on the subject. It’s what informed the decision to ban planting trees on deep peat. Check out forest research for actual papers but there are plenty out there.

To try and answer the OP, I think it’s a difficult circle to square to be honest. I did see once in N Ireland some deep peat growing good grass once. The owner said he just threw lime at it now and again, no fertiliser and no drains other than the standard ditch along the field boundary. No idea how that translated to carbon emissions etc, it was just quite an interesting field!

A ditch would have an effect I imagine, we might have a terminology confusion

 

[toquark]

A ditch would have an effect I imagine, we might have a terminology confusion

Yeah, from memory it was a 10ac field so the ditch/drain probably didn’t have too much of an effect beyond the immediate edge of the field. It didn’t feel soft to walk on and the grass looked well enough!

 

[penntor]

Used to be involved in peat bog research on Dartmoor ( as the grunt taking the cores), look at research by Paul Lunt, University of Plymouth.
Basically if peat bog wet the sphagnum moss is preserved and locked up, if it is allowed to dry out and oxygen gets into the peat it decomposes.