Impact of a plant-based diet-Large scale monocropping

Graeme M

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Non-vegans, especially farmers, often point to vegans as being responsible for causing environmental destruction by supporting large-scale monocropping. They say all the chickpeas and lentils and soy needed to feed vegans are doing this. Vegans on the other hand will say it is animal feed causing this problem. I was curious about this, so went off and did some calculations. They are very rough but it was surprising.

First up, right now, around 1.4 billion hectares are used to grow extensive "monoculture" crops such as wheat, rice, soy, barley, corn, palm oil crop and so on. Almost all of this is due to the demand for food etc from people. Very little is caused directly by plant-based diets and probably only a small percentage for animal feed.

If we could magically eliminate animal sourced food today, we'd need to replace those lost calories with plant sourced foods. As meat and dairy provide about 43% of all protein consumed by the world, we'd need a lot of protein dense plant foods. Presumably, we'd grow a lot more lentils, pulses, soy etc. On my calculations, we would reduce the land under monocultures by as little as 60-70 million hectares. That is, a plant-based diet tomorrow would reduce total land area under large scale crops by little more than 5%. While this is noticeable, it doesn't look like a plant-based diet is a good solution to the problem of monoculture cropping.
 
Almost all of this is due to the demand for food etc from people. Very little is caused directly by plant-based diets and probably only a small percentage for animal feed.
You're saying that animal feed accounts for only a small percentage of monoculture crops? That almost all monoculture crops are grown to feed people, not livestock/animals?
 
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. I was curious about this, so went off and did some calculations. They are very rough but it was surprising.

First up, right now, around 1.4 billion hectares are used to grow extensive "monoculture" crops such as wheat, rice, soy, barley, corn, palm oil crop and so on. Almost all of this is due to the demand for food etc from people. Very little is caused directly by plant-based diets and probably only a small percentage for animal feed.

If we could magically eliminate animal sourced food today, we'd need to replace those lost calories with plant sourced foods.

First off you seem to forget that those calories from animal sources don't magically appear. Modern cows and chickens and pigs all eat crops. Crops that are grown specifically for them - and not humans.

I think chickens are the most efficient of the bunch and are about 33% efficient in converting their feed to chicken. So just by dropping the middle man the efficiency of changing crops to calories increases by.... well you do the math.

I'm going to use corn as the next example. Granted corn is the worst offender but well... you will get the idea. About one-third of all the corn grown in the US goes to feed animals. If you don't feed cows you have a lot of corn leftover. What you should have is a lot of cropland left over. And without the cows being inefficient converters of corn to beef - that cropland will be able to feed even more humans.

And before you get into the "cows can eat grass" thing. Yes, they can. but modern cows are all finished in feedlots where they get fed corn.
 
Soooo many more uses!
The amount grown for whole foods for human consumption seems a very small amount. Even those for humans are made into thing like oil, highly processed sugars and fillers.

Same thing for corn. People only eat about 10% of the corn crop as corn. A big chunk goes to ethanol, too.
 
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If we could magically eliminate animal sourced food today, we'd need to replace those lost calories with plant sourced foods. As meat and dairy provide about 43% of all protein consumed by the world, we'd need a lot of protein dense plant foods. Presumably, we'd grow a lot more lentils, pulses, soy etc. On my calculations, we would reduce the land under monocultures by as little as 60-70 million hectares. That is, a plant-based diet tomorrow would reduce total land area under large scale crops by little more than 5%.
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The United States Department of Agriculture's findings appear to disagree with yours, although this is a very old report: https://naldc.nal.usda.gov/download/ORC00000242/PDF

Here is page 4 of this USDA report. Graeme, please show your data, links to data sources, and your calculations, for comparison.


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First up, right now, around 1.4 billion hectares are used to grow extensive "monoculture" crops such as wheat, rice, soy, barley, corn, palm oil crop and so on. Almost all of this is due to the demand for food etc from people. Very little is caused directly by plant-based diets and probably only a small percentage for animal feed.
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According to the United Nations Food and Agriculture Organization (FAO), almost 50% of the world's grain production is fed to livestock (see Box 1 of this report: Livestock - a driving force for food security and sustainable development )
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Bear in mind I am limiting this analysis only to large-scale monocropping, so I haven't assessed any impacts on pasture. The relevant numbers as I get them from Our World In Data are:

Cereals (wheat and rice): 700 million hectares
Coarse grains (corn, barley, sorghum etc): 350 million hectares
Oil crops (soy, palm): 300 million hectares

Almost all of the wheat and rice is grown for human consumption, though some proportion is fed to animals (low quality crop not able to be used for human food, mostly).

Much of the coarse grains are grown for food in poorer countries, though in the OECD it is mostly for feed and biofuel. I haven't found a good figure for this, though the FAO report linked above suggests 50%. I used 30% because we aren't interested in the portion for biofuel.

Oil crops are grown largely for human use in cooking, biofuels and industrial uses. Almost all soy is grown for human use primarily.

Eliminating animals would result in the loss of demand for coarse grains used as feed (30% of 350 million hectares, or 115 million hectares) and for the loss of about 7% of soy production (guessed at 7 million hectares - I think there are about 100 million hectares under soy globally). Additionally, with the loss of demand for feed, much of the soy crop may be replaced by palm as it is much higher yield per hectare. This may be wrong and total soy may not change much at all. As well, without meat we might see a modest reduction in demand for cooking oil - I assumed 10% but it may be more or less in fact. Altogether, I estimate a saving of around 200 million hectares.

Balanced against this is the need for protein to replace the lost meat. I used an average for this rather than actuals as we eat too much meat. An average person weighs 62kg, he needs .8g/kg protein, globally averaged we get around 43% protein from meat and there are 7.8 billion of us. I also assumed we'd use protein crops such as soy, lentils, pulses etc. This means we need 325 billion kg of such crops annually, at an average yield of 2500kg/hectare we need 130 million hectares.

That means we save as little as 70 million hectares in total.
 
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Bear in mind I am limiting this analysis only to large-scale monocropping, so I haven't assessed any impacts on pasture. The relevant numbers as I get them from Our World In Data are:

Cereals (wheat and rice): 700 million hectares
Coarse grains (corn, barley, sorghum etc): 350 million hectares
Oil crops (soy, palm): 300 million hectares

Almost all of the wheat and rice is grown for human consumption, though some proportion is fed to animals (low quality crop not able to be used for human food, mostly).

Much of the coarse grains are grown for food in poorer countries, though in the OECD it is mostly for feed and biofuel. I haven't found a good figure for this, though the FAO report linked above suggests 50%. I used 30% because we aren't interested in the portion for biofuel.

Oil crops are grown largely for human use in cooking, biofuels and industrial uses. Almost all soy is grown for human use primarily.

Eliminating animals would result in the loss of demand for coarse grains used as feed (30% of 350 million hectares, or 115 million hectares) and for the loss of about 7% of soy production (guessed at 7 million hectares - I think there are about 100 million hectares under soy globally). Additionally, with the loss of demand for feed, much of the soy crop may be replaced by palm as it is much higher yield per hectare. This may be wrong and total soy may not change much at all. As well, without meat we might see a modest reduction in demand for cooking oil - I assumed 10% but it may be more or less in fact. Altogether, I estimate a saving of around 200 million hectares.

Balanced against this is the need for protein to replace the lost meat. I used an average for this rather than actuals as we eat too much meat. An average person weighs 62kg, he needs .8g/kg protein, globally averaged we get around 43% protein from meat and there are 7.8 billion of us. I also assumed we'd use protein crops such as soy, lentils, pulses etc. This means we need 325 billion kg of such crops annually, at an average yield of 2500kg/hectare we need 130 million hectares.

That means we save as little as 70 million hectares in total.
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Please provide weblinks to each of these data. You're citing a lot of data for crop yields and crop protein content, but these data can't be verified without seeing your sources. Please tighten up your analysis.

Thank you.
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Much of the coarse grains are grown for food in poorer countries, though in the OECD it is mostly for feed and biofuel. I haven't found a good figure for this, though the FAO report linked above suggests 50%. I used 30% because we aren't interested in the portion for biofuel.
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How do you calculate that only 30% of the world's grain production is used for animal feed? The FAO report states that 50% of grain is used for animal feed: Livestock - a driving force for food security and sustainable development .
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Soy is grown for human use almost exclusively. About 6% globally just for human food, 7% for feed only and the balance - 87% - for oil. That 87% delivers about 20% oil and 80% feed from the same source stock. The demand for oil drives oil crops overall, but the demand for feed drives the increase in share by soy.

I used 30% because I couldn't find a specific figure but that more or less matched the data I was finding. Is that FAO report current? Note that it wouldn't make a particularly big difference to the final result, but I would like to get a better source of data on that stat. Use for biofuel has increased in recent years and in any case, it might be that while a lot is fed to animals, it starts as intended for human consumption. Farmers sell low quality yields to the feed market.

The areas under crops I got from Our World In Data.


Land Use (scroll down to Land Use By Crop).
 
Soy is grown for human use almost exclusively. About 6% globally just for human food, 7% for feed only and the balance - 87% - for oil. That 87% delivers about 20% oil and 80% feed from the same source stock. The demand for oil drives oil crops overall, but the demand for feed drives the increase in share by soy.

I used 30% because I couldn't find a specific figure but that more or less matched the data I was finding. Is that FAO report current? Note that it wouldn't make a particularly big difference to the final result, but I would like to get a better source of data on that stat. Use for biofuel has increased in recent years and in any case, it might be that while a lot is fed to animals, it starts as intended for human consumption. Farmers sell low quality yields to the feed market.

The areas under crops I got from Our World In Data.


Land Use (scroll down to Land Use By Crop).
Please read your cited article more carefully. It says that 75% of soy is used for animal feed.
 
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David3, yes, but that's talking about a by-weight measurement. 13% of soy is used directly for food and feed. 87% is processed and of that 87%, around 80% by weight is used for mealcake and 20% by weight is oil. So ALL of that 87% is used for human supply chains. 93% of all soy grown is specifically for human use. Only 7% appears to be grown directly for animal feed. That means that about 93 million hectares is used to grow soy for human use and just 7 million for animal feed. Figures do vary, but generally they come out to around these proportions which is why I linked that reference - it's about the best concise summary I have found.
 
Almost all soy is grown for human use primarily.
Around 70 percent of the world's soy is fed directly to livestock and only six percent of soy is turned into human food, which is mostly consumed in Asia. The rest of soy is turned into soybean oil.


Just over 70 percent of the soybeans grown in the United States are used for animal feed, with poultry being the number one livestock sector consuming soybeans, followed by hogs, dairy, beef and aquaculture.

 
Lou, no, that is a misinterpretation. Reread my comment above and the source I referenced.
From your source

"99% of soy cake is used as an animal feed ingredient (see Figure 3 and 5) – mostly in pig and poultry farming (respectively 29% and 53%), but also in aquaculture (8%) and dairy farming (2%). Less than 1% of soy cake is used for human consumption. This is further processed into protein-rich food ingredients such as textured vegetable protein. Because of its high protein content and meaty texture, textured soy protein is often used in products such as vegetable burgers."
 
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Lou, it works like this. Using that source's figures, 7% of soy grown is used directly to feed animals. 6% is food for people (eg tofu, edamame, soy milk etc). What is left, 87% of the soy yield globally, is crushed for oil. The left over residue after the crush is used as mealcake for livestock feed. So, the same source soy beans deliver two products - oil and meal. However, the actual primary demand is oil for human use. All that has happened is the happy confluence of the two demands being met by soy (happy for the grower, that is). So, the world oil crop is less dominated by palm oil and an increasing share is soy oil because of the economic value proposition for soy. Presumably this has also led to a lower demand for some other feed stocks such as corn, but I don't know about that given the huge increase in meat consumption. Perhaps all sources of animal feed are increasing.
 
Lou, it works like this. Using that source's figures, 7% of soy grown is used directly to feed animals. 6% is food for people (eg tofu, edamame, soy milk etc). What is left, 87% of the soy yield globally, is crushed for oil. The left over residue after the crush is used as mealcake for livestock feed. So, the same source soy beans deliver two products - oil and meal. However, the actual primary demand is oil for human use. All that has happened is the happy confluence of the two demands being met by soy (happy for the grower, that is). So, the world oil crop is less dominated by palm oil and an increasing share is soy oil because of the economic value proposition for soy. Presumably this has also led to a lower demand for some other feed stocks such as corn, but I don't know about that given the huge increase in meat consumption. Perhaps all sources of animal feed are increasing.
1-Where is the protein in soybean oil?

2- Low fat plant based diet does not use oil.

3-People are overeating protein right now so maybe you do not even need to supply the same amount through plant sources but it's probably not a problem since meat is a very inefficient way to produce nutrients. And before you mention people still need to fill their stomachs you can watch this video starting in 1:37

4- What about all the land that is being used as pasture and for which also rain forest is being destroyed? Not all is suitable to grow grains but how much can be? And can't some be used for fruit or nuts or other plant based foods.
 
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I am not sure I see the relevance of your points, fakei. No, there is no protein in vegetable oil. What does that have to do with this analysis? Low fat diets of any kind presumably use little vegetable oil, but again what is the relevance? As for over-consumption of protein, my calculations use the RDI for protein. If we factor in some sort of discretionary over-consumption, the results may well be different, but I suspect not by much. The analysis is only about large-scale monocropping, not pasture land. Land clearing to grow these crops is the same problem under either scenario, because the demand for plants is the cause.