Carbon content of foodstuffs.

[melted welly]

This is a question for people cleverer than I, because I can’t find an immediate answer online, and I don’t know how to work it out myself.

We, all of us, grow food. Be it beef, lamb, potatoes, cereals etc etc. All of this is made up of a % of the co2 either the plant has sequestered, or the plant the animal eats has sequestered.

Therefore, every kg of produce leaving our farms contains a % of C that we have sequestered in the growing process.

I want to know (roughly) how much carbon is in each kg of wheat, barley, osr, potatoes, carrots, rhubarb and triticale leaves our farm. But I cannot for the life of me find any figures anywhere. My wife is going to work it out by scientific means which I don’t understand, but I’m a bit impatient to wait till this evening.

Has anyone done the figures and worked it out for their produce?

My reasoning is that, our carbon audit includes all our inputs as emissions, includes our “crops” in emissions (429t). In my sequestration part, there is no sequestration figure attributed to crops. But that cannot be right, if I plant 1 potato, get 6 back and sell them, then I’ve captured and sold more C (in potato form) than I bought. So that should count as sequestration. But it doesn’t.

So if anyone has any pointers as to how to work it out, I’d be very grateful as I’m having a discussion about this tomorrow am.

 

[ollie989898]

1 tonne of spuds has a dry matter of what, 20 percent, tops?

What isn't water is either an organic substance (lipids, carbohydrates or proteins- these all contain carbon atoms, more for lipids but less for proteins) plus a little bit of inorganic content (i.e. minerals like magnesium and calcium). You need to find a very simple food molecule and then work it out on a carbon percentage of each mole of that substance.

I remember the human body is roughly something like 18% carbon by mass.

Grain I suspect will be somewhat higher. This paper discusses it here:

Carbon fluxes from a spring wheat–corn–soybean crop rotation under no‐tillage management
The increase in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in rainfed cropping systems of the northern Great Plains (NGP) has altered the delivery of ecosystem services from agricultural land. To date, there is limited understanding about how these crops affect the carbon (C) balance of cropping systems in the region when included in a short rotation window. This study sought to quantify C balance of a spring wheat (Triticum aestivum L.)–corn—soybean rotation under no‐tillage management using eddy covariance (EC) techniques. Paired field sites with the same soil type near Mandan, ND, were used for the study. Annual net ecosystem production (NEP) by crop was –34, 120, and 7 g C m–2 y–1 for spring wheat, corn, and soybean, respectively. Carbon removed in grain over the rotation was less than a third of C lost by ecosystem respiration (ER) (210 vs. 674 g C m–2 y–1). After accounting for grain C removal, net ecosystem carbon balance (NECB) was –164, –253, and –121 g m–2 y–1 for spring wheat, corn, and soybean, respectively, with a mean NECB of –179 ± 39 g C m–2 y–1 (P = .043; t test for difference from zero), implying the rotation was a net C source. Time associated with active crop growth each year was 27% for spring wheat, 41% for corn, and 28% for soybean. Management strategies that lengthen the period of biomass growth may mitigate C loss from spring wheat–corn–soybean rotations in the NGP. Eddy covariance methods were used to quantify CO2 fluxes from a wheat–corn–soybean rotation. Annual net ecosystem production was negative for wheat, positive for corn, and near zero for soybean. Carbon removed in grain was less than a third of carbon lost by ecosystem respiration. Net ecosystem carbon balance for the rotation was negative, implying carbon loss.
View
... growing seasons (Table 3). When removal of carbon from grain harvest was accounted, assuming 40% of carbon content in wheat grains (Kumar et al., 2014), the loss of carbon is estimated to be 40 g C m − 2 for removal of 1 t ha − 1 (100 g m − 2 ) grains. Net ecosystem carbon balance (NECB), calculated as the difference between net ecosystem production (NEP = -NEE) and carbon removal through grain harvest, would range from 311 to 370 g C m − 2 for grain-only wheat and from 112 to 317 g C m − 2 for graze-grain wheat. ...

 

[melted welly]

1 tonne of spuds has a dry matter of what, 20 percent, tops?

What isn't water is either an organic substance (lipids, carbohydrates or proteins- these all contain carbon atoms, more for lipids but less for proteins) plus a little bit of inorganic content (i.e. minerals like magnesium and calcium). You need to find a very simple food molecule and then work it out on a carbon percentage of each mole of that substance.

I remember the human body is roughly something like 18% carbon by mass.

Grain I suspect will be somewhat higher. This paper discusses it here:

Carbon fluxes from a spring wheat–corn–soybean crop rotation under no‐tillage management
The increase in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in rainfed cropping systems of the northern Great Plains (NGP) has altered the delivery of ecosystem services from agricultural land. To date, there is limited understanding about how these crops affect the carbon (C) balance of cropping systems in the region when included in a short rotation window. This study sought to quantify C balance of a spring wheat (Triticum aestivum L.)–corn—soybean rotation under no‐tillage management using eddy covariance (EC) techniques. Paired field sites with the same soil type near Mandan, ND, were used for the study. Annual net ecosystem production (NEP) by crop was –34, 120, and 7 g C m–2 y–1 for spring wheat, corn, and soybean, respectively. Carbon removed in grain over the rotation was less than a third of C lost by ecosystem respiration (ER) (210 vs. 674 g C m–2 y–1). After accounting for grain C removal, net ecosystem carbon balance (NECB) was –164, –253, and –121 g m–2 y–1 for spring wheat, corn, and soybean, respectively, with a mean NECB of –179 ± 39 g C m–2 y–1 (P = .043; t test for difference from zero), implying the rotation was a net C source. Time associated with active crop growth each year was 27% for spring wheat, 41% for corn, and 28% for soybean. Management strategies that lengthen the period of biomass growth may mitigate C loss from spring wheat–corn–soybean rotations in the NGP. Eddy covariance methods were used to quantify CO2 fluxes from a wheat–corn–soybean rotation. Annual net ecosystem production was negative for wheat, positive for corn, and near zero for soybean. Carbon removed in grain was less than a third of carbon lost by ecosystem respiration. Net ecosystem carbon balance for the rotation was negative, implying carbon loss.
View
... growing seasons (Table 3). When removal of carbon from grain harvest was accounted, assuming 40% of carbon content in wheat grains (Kumar et al., 2014), the loss of carbon is estimated to be 40 g C m − 2 for removal of 1 t ha − 1 (100 g m − 2 ) grains. Net ecosystem carbon balance (NECB), calculated as the difference between net ecosystem production (NEP = -NEE) and carbon removal through grain harvest, would range from 311 to 370 g C m − 2 for grain-only wheat and from 112 to 317 g C m − 2 for graze-grain wheat. ...

Would animal bodies be similar to human bodies in the % carbon by mass calculations do you think?

 

[ollie989898]

Would animal bodies be similar to human bodies in the % carbon by mass calculations do you think?

I would think all mammals would be broadly similar.

 

[melted welly]

If attribute a 40% figure to grains, and put arbitrary figure of 20% to veg, suddenly I’m carbon negative.

Further confirming my views on net zero fascination and carbon trading, it fecking stinks.

 

[betweenthelines]

Diamonds and coal are pure carbon.

Foodstuffs contain carbon compounds (usually known as carbohydrates) which also contain oxygen and other elements.


Crops will draw C02 from the atmosphere to create carbohydrates so the question is pointless.

You might as well ask if the farmer exhales on his farm or elsewhere (humans exhale CO2)

 

[melted welly]

Diamonds and coal are pure carbon.

Foodstuffs contain carbon compounds (usually known as carbohydrates) which also contain oxygen and other elements.


Crops will draw C02 from the atmosphere to create carbohydrates so the question is pointless.

You might as well ask if the farmer exhales on his farm or elsewhere (humans exhale CO2)

It’s not pointless.

we’re being made the kicking boy, where we bear the “footprint” of both inputs and outputs. And it’s just taken on board as our burden to bear.

none of this net zero, carbon trading is going to go away so we need to fight our corner or we’ll be royally shafted by it.

 

[soapsud]

Diamonds and coal are pure carbon.

Foodstuffs contain carbon compounds (usually known as carbohydrates) which also contain oxygen and other elements.


Crops will draw C02 from the atmosphere to create carbohydrates so the question is pointless.

You might as well ask if the farmer exhales on his farm or elsewhere (humans exhale CO2)

On your last point, I agree we are all part of the one big whole and therefore co-dependent but the question of growth and development in the animal kingdom and their sequestering of carbon is still an interesting idea. I say this in the context of the many here on TFF saying how over populated we are.

 

[Grass And Grain]

We capture the carbon. We sell on the carbon containing products. Folk buy it, eat it, respire back out the CO2, so the consumer is the polluter in this case.

We can't claim credit for the photosynthesis AND the sale of the carbon producing product. That would be double counting of the same thing. However, we could claim some carbon sequestration by adding to soil OM, AND sale of our carbon containing products.

 

[melted welly]

We capture the carbon. We sell on the carbon containing products. Folk buy it, eat it, respire back out the CO2, so the consumer is the polluter in this case.

We can't claim credit for the photosynthesis AND the sale of the carbon producing product. That would be double counting of the same thing. However, we could claim some carbon sequestration by adding to soil OM, AND sale of our carbon containing products.

thats what I’m getting at.

we know how much produce we sell, so if we know the C content of the produce, then it’s a fairly simple calculation to work out C sequestered surely

those credits could then be sold retrospectively, negating the need for the shyster schemes.

 

[DaveGrohl]

We capture the carbon. We sell on the carbon containing products. Folk buy it, eat it, respire back out the CO2, so the consumer is the polluter in this case.

We can't claim credit for the photosynthesis AND the sale of the carbon producing product. That would be double counting of the same thing. However, we could claim some carbon sequestration by adding to soil OM, AND sale of our carbon containing products.

Why’s it double accounting? We’re absorbing CO2 from the atmosphere and it leaves the farm as stored carbon with a lower CO2 atmospheric % alongside. No other industry worries about double accounting anyway, but again, why are you calling this double accounting?

 

[How Dairy]

It depends whether you are calculating carbon atoms or something else. Carbon is in pretty much everything. You have to count the 'C's. It'd be difficult to claim that muscle and fat contained more carbon than starch etc.

Glucose is C(6)H(12)O(6) and is a monosaccharide, two of these form a disaccharide like sucrose or fructose etc. Multiples of this form starch or cellulose.

Amino acids are H(2)NCH RCOOH and multiples of these make up proteins which make up muscle.

Fatty acids are made of a carbon backbone with e.g. C(6)H(7)COOH. Multiples of these make up fats.

Then you produce Urea CH(4)N(2)O, Carbon Dioxide CO(2), Methane CH(4) (the latter two have the same number of 'C's per molecule but are counted differently as their carbon 'warming' effect is different and we know about the debate on this!!)

 

[How Dairy]

thats what I’m getting at.

we know how much produce we sell, so if we know the C content of the produce, then it’s a fairly simple calculation to work out C sequestered surely

those credits could then be sold retrospectively, negating the need for the shyster schemes.

So if we produce more from less land, we are more environmentally friendly? (caveat on inputs required to get there!).

I am not sure that would stand up well for livestock if I'm honest. Is there more carbon in muscle and fat than starch, cellulose and sugar? If not, it is easier to demonstrate carbon sequestered from a crop than livestock you feed that crop to - ahhhh then you have ploughing and permanent pasture and grass vs cropping - it's getting too complicated .

It is definitely not simple!

 

[soapsud]

Separating carbon capturing process from carbon holding produce does suggest an allocation of carbon-releasing responsibility between food producers and retailer-processors though?

I'm still interested in the growth of individual animals as carbon sequesters. I'm too stupid to try and work it out but I can see that:
- barley -> beer/whiskey -> pint/dram would be less than
- barley -> animal feed -> meat on a plate
as each has a carbon calculatable cost for every step in the process

... not that I'm proposing we drink more and eat less!

 

[Derrick Hughes]

What about Footprints
Other that what the anti farming lobby print

 

[melted welly]

So if we produce more from less land, we are more environmentally friendly? (caveat on inputs required to get there!).

I am not sure that would stand up well for livestock if I'm honest. Is there more carbon in muscle and fat than starch, cellulose and sugar? If not, it is easier to demonstrate carbon sequestered from a crop than livestock you feed that crop to - ahhhh then you have ploughing and permanent pasture and grass vs cropping - it's getting too complicated .

It is definitely not simple!

It’s not simple at all.

we grow cereals and veg. Where I’m coming from is that my inputs to my system (fert, chems, fuel, lime, machinery) are all counted for in my emissions.

So the produce of others which I have used goes in my emissions column.

By that logic all the carbon containing material which leaves the farm should be in the sequestered column as a proportion of which I sell is carbon. it is sold as there is a demand, therefore the creator of that demand is responsible for it. That’s how it works for fuel, oil, electricity, so why not food??…….

The only reason is that it would shine a light where it isn’t wanted.

 

[soapsud]

It’s not simple at all.

we grow cereals and veg. Where I’m coming from is that my inputs to my system (fert, chems, fuel, lime, machinery) are all counted for in my emissions.

So the produce of others which I have used goes in my emissions column.

By that logic all the carbon containing material which leaves the farm should be in the sequestered column as a proportion of which I sell is carbon. it is sold as there is a demand, therefore the creator of that demand is responsible for it. That’s how it works for fuel, oil, electricity, so why not food??…….

The only reason is that it would shine a light where it isn’t wanted.

Would you say it's the use and consumption of raw inputs supplied in that count as emissions against you?
If so, how is that different from a shopper buying and consuming your cereals and veg?
Food shoppers need inputs to carry on going about their daily lives.
One consequence of this shifts the cost from farmers to their customers. It would simply mean that a carbon tax will, in effect and probably indirectly, be put on food.

 

[farmerm]

We capture the carbon. We sell on the carbon containing products. Folk buy it, eat it, respire back out the CO2, so the consumer is the polluter in this case.

We can't claim credit for the photosynthesis AND the sale of the carbon producing product. That would be double counting of the same thing. However, we could claim some carbon sequestration by adding to soil OM, AND sale of our carbon containing products.

What is this scheme that allows me to claim credits for photosynthesis, I am not aware of this....

My understanding is current schemes pay for carbon sequestation in the soil but not the carbon sequestered in our products.

Carbon in the air or in biomass above ground or biomass in topsoil is all transient!

If carbon is to be taxed to reduce carbon emissions is should be taxed at one point and one point only, the point when it is taken out of deep ground storage and added to the active carbon cycle, everything else is just pointless reshuffling chairs on the deck

 

[Grass And Grain]

What is this scheme that allows me to claim credits for photosynthesis, I am not aware of this....

My understanding is current schemes pay for carbon sequestation in the soil but not the carbon sequestered in our products.

Carbon in the air or in biomass above ground or biomass in topsoil is all transient!

If carbon is to be taxed to reduce carbon emissions is should be taxed at one point and one point only, the point when it is taken out of deep ground storage and added to the active carbon cycle, everything else is just pointless reshuffling chairs on the deck

Actually, yes, agree, you're correct, agricultural production just cycles carbon. What is respired by the human being is same as what was captured by the plant . It's a bit like burning biomass isn't it. Cyclical.

 

[melted welly]

Would you say it's the use and consumption of raw inputs supplied in that count as emissions against you?
If so, how is that different from a shopper buying and consuming your cereals and veg?
Food shoppers need inputs to carry on going about their daily lives.
One consequence of this shifts the cost from farmers to their customers. It would simply mean that a carbon tax will, in effect and probably indirectly, be put on food.

Yes, my inputs are in the emissions column, yet my outputs do not feature in the sequestration column.

I’m interested as to how other industries count it.

Eg if a bakery has a carbon audit, does it just look at say, energy use, transport and packaging, or does it include a value for the ingredients?

The ingredients are just passing through, the consumer is at the end of the chain.

If the consumer wasn’t there, the bakery wouldn’t exist and the land wouldn’t have produced the wheat.