Impact of a plant-based diet-Large scale monocropping

[Graeme M]

More than three-quarters (77%) of global soy is fed to livestock for meat and dairy production. Most of the rest is used for biofuels, industry or vegetable oils. Just 7% of soy is used directly for human food products such as tofu, soy milk, edamame beans, and tempeh.

In the context of the discussion, it's a bit misleading to think of 77% of all soy grown being used to feed animals. Something like that is probably the proportion by weight, but it isn't in terms of actual purpose. I think too that graphic may be mixing up different methods of evaluation. At its simplest, of all the soy grown, about 7% is used for human food and 7% used for animal feed. The rest, about 86% of the soy grown, is used to produce vegetable oil which is then used in a variety of human applications like cooking, baking, biofuels and industrial uses. So nearly all soy (and hence area under soy) is actually being used for human applications.

 

[Graeme M]

a vegan diet would demand a total of just 3m

Three million hectares to produce enough food to feed all Britons? I'd like to see the calculations. The global average protein requirement per person is about 50g/day I think. A reasonable rule of thumb is to multiply by about 6 to work out how much plant food such as lentils or soy is needed to return the 50g, which comes to about 300g/day or 110kg/year. As those sorts of crops yield maybe 1500kg/hectare on average, we'd need about 4.5 million hectares. The UK has about 3-3.5 million arable hectares. Still, it does show that a vegan diet requires a lot less land.

 

[Lou]

Three million hectares to produce enough food to feed all Britons? I'd like to see the calculations.

I believe this contains those calculatons

 

[Graeme M]

I believe this contains those calculatons

Yes, and the downloadable PDF contains the tables. I think there are a few assumptions smoothing over some uncertainties, so I feel the calculations are a bit optimistic. However, the main points appear to be that an organic version would require about 7.2 million hectares to feed the UK population, while the 3.1 million hectares Monbiot talks about would require extensive chemical inputs (ie synthetic fertilisers, pesticides etc). The claim about 200 million people is if some proportion of non-arable land were used to grow crops as well. As the UK only has about 4 million hectares of arable land, I'm not sure there is enough land for a vegan system to deliver enough food. Still, it does highlight that a vegan system produces a lot more for a lot less land.

 

[LoreD]

In the context of the discussion, it's a bit misleading to think of 77% of all soy grown being used to feed animals. Something like that is probably the proportion by weight, but it isn't in terms of actual purpose. I think too that graphic may be mixing up different methods of evaluation. At its simplest, of all the soy grown, about 7% is used for human food and 7% used for animal feed. The rest, about 86% of the soy grown, is used to produce vegetable oil which is then used in a variety of human applications like cooking, baking, biofuels and industrial uses. So nearly all soy (and hence area under soy) is actually being used for human applications.

I' m not really sure why you are arguing that a vegan diet doesn't help the planet; and that a meat based diet does very minimal damage to the planet.

All of the credible sources are very clear that animal agriculture is the single biggest driver of climate change.

It is just confusing to me that a vegan is using the omnivore/carnivore talking points.

 

[Graeme M]

I' m not really sure why you are arguing that a vegan diet doesn't help the planet; and that a meat based diet does very minimal damage to the planet.

All of the credible sources are very clear that animal agriculture is the single biggest driver of climate change.

It is just confusing to me that a vegan is using the omnivore/carnivore talking points.

LoreD, that isn't quite what I've said. In that comment, I am pointing out that it's a mistake to assume that we grow so much soy purely to feed animals. So much soy IS grown to feed animals, but most of it is also used for us. In the absence of animal feed as a market, we still need just as much soy, or some alternative crop.

I agree that doing far less animal farming would reduce a range of negative impacts such as land clearing, environmental degradation, emissions and so on. But I think it's a mistake to assume that animal farming can never be good for the land, in fact it can. The alternative is to grow crops which are not good for the land - land must be cleared, biodiversity reduced, artificial inputs used, and vast numbers of animals killed. Globally, we have about two billion hectares of arable land which can be used, we are already using 1.6 billion of those. Eliminating animals and replacing them with crops wouldn't save much of the croplands; I estimate we'd still end up with perhaps 1.2-1.4 billion hectares under crops. And that must grow over time as population grows. So, is a plant-based diet really best for the world?

I'm not so sure.

 

[David3]

LoreD, that isn't quite what I've said. In that comment, I am pointing out that it's a mistake to assume that we grow so much soy purely to feed animals. So much soy IS grown to feed animals, but most of it is also used for us. In the absence of animal feed as a market, we still need just as much soy, or some alternative crop.

I agree that doing far less animal farming would reduce a range of negative impacts such as land clearing, environmental degradation, emissions and so on. But I think it's a mistake to assume that animal farming can never be good for the land, in fact it can. The alternative is to grow crops which are not good for the land - land must be cleared, biodiversity reduced, artificial inputs used, and vast numbers of animals killed. Globally, we have about two billion hectares of arable land which can be used, we are already using 1.6 billion of those. Eliminating animals and replacing them with crops wouldn't save much of the croplands; I estimate we'd still end up with perhaps 1.2-1.4 billion hectares under crops. And that must grow over time as population grows. So, is a plant-based diet really best for the world?

I'm not so sure.

.
Please present sources for your calculations.
.

 

[LoreD]

More than three-quarters (77%) of global soy is fed to livestock for meat and dairy production. Most of the rest is used for biofuels, industry or vegetable oils. Just 7% of soy is used directly for human food products such as tofu, soy milk, edamame beans, and tempeh.

Drivers of Deforestation

The world loses 5 million hectares of forest each year. What activities are driving this?

ourworldindata.org

 

[LoreD]

LoreD, that isn't quite what I've said. In that comment, I am pointing out that it's a mistake to assume that we grow so much soy purely to feed animals. So much soy IS grown to feed animals, but most of it is also used for us. In the absence of animal feed as a market, we still need just as much soy, or some alternative crop.

I agree that doing far less animal farming would reduce a range of negative impacts such as land clearing, environmental degradation, emissions and so on. But I think it's a mistake to assume that animal farming can never be good for the land, in fact it can. The alternative is to grow crops which are not good for the land - land must be cleared, biodiversity reduced, artificial inputs used, and vast numbers of animals killed. Globally, we have about two billion hectares of arable land which can be used, we are already using 1.6 billion of those. Eliminating animals and replacing them with crops wouldn't save much of the croplands; I estimate we'd still end up with perhaps 1.2-1.4 billion hectares under crops. And that must grow over time as population grows. So, is a plant-based diet really best for the world?

I'm not so sure.

All of the sources point out that more 3/4 of soy and grain is fed to animals.

I'm not really sure why you are arguing meat industry talking points on a vegan forum?

 

[David3]

According to Beef Magazine, the feed conversion ratio for feedlot beef is 6:1 (6 pounds of feed are necessary for the cattle to gain 1 pound of weight): Supplement Conversion Ratio . This isn't an efficient use of soy and grain.

 

[LoreD]

According to Beef Magazine, the feed conversion ratio for feedlot beef is 6:1 (6 pounds of feed are necessary for the cattle to gain 1 pound of weight): Supplement Conversion Ratio . This isn't an efficient use of soy and grain.

All the evidence now points in one direction: the crucial shift is from an animal- to a plant-based diet. A paper published last week in Science reveals that while some kinds of meat and dairy production are more damaging than others, all are more harmful to the living world than growing plant protein. It shows that animal farming takes up 83% of the world’s agricultural land, but delivers only 18% of our calories. A plant-based diet cuts the use of land by 76% and halves the greenhouse gases and other pollution that are caused by food production.

93% of the soya we consume, which drives the destruction of forest, savannah and marshland, is embedded in meat, dairy, eggs and fish, and most of it is lost in conversion. When we eat it directly, much less of the crop is required to deliver the same amount of protein.

The best way to save the planet? Drop meat and dairy | George Monbiot

Farming livestock for food threatens all life on earth, and ‘free-range’ steak is the worst of all, writes Guardian columnist George Monbiot

www.theguardian.com

 

[Lou]

All the evidence now points in one direction: the crucial shift is from an animal- to a plant-based diet. A paper published last week in Science reveals that while some kinds of meat and dairy production are more damaging than others, all are more harmful to the living world than growing plant protein. It shows that animal farming takes up 83% of the world’s agricultural land, but delivers only 18% of our calories. A plant-based diet cuts the use of land by 76% and halves the greenhouse gases and other pollution that are caused by food production.

93% of the soya we consume, which drives the destruction of forest, savannah and marshland, is embedded in meat, dairy, eggs and fish, and most of it is lost in conversion. When we eat it directly, much less of the crop is required to deliver the same amount of protein.

The best way to save the planet? Drop meat and dairy | George Monbiot

Farming livestock for food threatens all life on earth, and ‘free-range’ steak is the worst of all, writes Guardian columnist George Monbiot

www.theguardian.com

That is the same author for the article I cited that rekindled this conversation.
But yeah, I'm with @LoreD and @David3.
All the complex data and math is interesting but really all you have to know is that livestock do Not convert crops to food at 100% (obviously) and we can make more food on more land if we just cut out the middleman.

And sure the concept that some lands are not suitable for crops but can support livestock is interesting. but in the US, most pigs and chickens are fed crops from day one. Although most cows are born and spend time on range land, they are quickly shipped off to places where they are fed animal feed. Again in the US, only a small precentage of beef in the stores is grass -fed. ( its in the single digits). so I don't even consider that significant.

 

[silva]

LoreD, that isn't quite what I've said. In that comment, I am pointing out that it's a mistake to assume that we grow so much soy purely to feed animals. So much soy IS grown to feed animals, but most of it is also used for us. In the absence of animal feed as a market, we still need just as much soy, or some alternative crop.

I agree that doing far less animal farming would reduce a range of negative impacts such as land clearing, environmental degradation, emissions and so on. But I think it's a mistake to assume that animal farming can never be good for the land, in fact it can. The alternative is to grow crops which are not good for the land - land must be cleared, biodiversity reduced, artificial inputs used, and vast numbers of animals killed. Globally, we have about two billion hectares of arable land which can be used, we are already using 1.6 billion of those. Eliminating animals and replacing them with crops wouldn't save much of the croplands; I estimate we'd still end up with perhaps 1.2-1.4 billion hectares under crops. And that must grow over time as population grows. So, is a plant-based diet really best for the world?

I'm not so sure.

Your arguments don't add up. You say animal farming can be good for the land, yet you don't expand on how.
Your argument that converting land used for animals to land used for plants for human consumption would require vast numbers of animals killed --land used for animals bred for human food requires vast numbers of wildlife killed off.
As it's been continually pointed out, raising animals for food requires 6 x's the feed that has to be grown elsewhere to feed the animals fed to people. Your insistence that eliminating animals and replacing replacing them with crops wouldn't save much of the croplands doesn't add up. Eliminate the animals and you eliminate the need for as much cropland.
You completely miss the amount of water used for animals, both for their own consumption, and for the cleaning. You don't mention what happens to the animals waste products


Another point that gets lost is that crops do not need to be grown on land

 

[LoreD]

Your arguments don't add up. You say animal farming can be good for the land, yet you don't expand on how.
Your argument that converting land used for animals to land used for plants for human consumption would require vast numbers of animals killed --land used for animals bred for human food requires vast numbers of wildlife killed off.
As it's been continually pointed out, raising animals for food requires 6 x's the feed that has to be grown elsewhere to feed the animals fed to people. Your insistence that eliminating animals and replacing replacing them with crops wouldn't save much of the croplands doesn't add up. Eliminate the animals and you eliminate the need for as much cropland.
You completely miss the amount of water used for animals, both for their own consumption, and for the cleaning. You don't mention what happens to the animals waste products


Another point that gets lost is that crops do not need to be grown on land

I watched a documentary about a conservancy that purchased bankrupt dairy farms and just let them go back to way they were before farming. It was really fascinating how fast forests, grasslands, and meadows reappeared. Within about 20 years the forest was thriving. They didn't plant anything. The land did it all by itself.

 

[Lou]

I watched a documentary about a conservancy that purchased bankrupt dairy farms and just let them go back to way they were before farming. It was really fascinating how fast forests, grasslands, and meadows reappeared. Within about 20 years the forest was thriving. They didn't plant anything. The land did it all by itself.

That would have been an old fashioned dairy farm. New fangled dairy farms are stainless steel and concrete.

Here in California some old dairy farms are being converted to almond orchards. With modern irrigation they still use less water. Not sure how it compares in other ways. It would be interesting to find out.

California Dairy Farmers Are Switching to Almonds

Faced with declining milk sales, California dairy farmers are "diversifying" with almond groves as vegan milk sales continue to climb.

www.livekindly.co

 

[Graeme M]

Please present sources for your calculations.

Ok. Of course, this is an educated guess, so you can take it as seriously as you wish, but it IS backed by some empirical data.

Our World in Data tells us that currently, about 1.6 billion hectares are used for crops (which includes all possible uses such as food, feed, biofuels, textiles and so on). See Our World in data (though this is now several years out of date, so it may be a little more):

Cropland extent over the long-term

Total cropland area, measured in hectares. Cropland refers to the area defined by the UN Food and Agricultural Organization (FAO) as 'arable land and permanent crops'.

ourworldindata.org

Now, some proportion is utilised for animal feed, but it isn't clear exactly how much. According to the FAO in Mottett et al (2017), the area is about 550 million hectares, though I am unsure of the definition for "feed" crops (for example, soy is a feed crop by FAO definition yet most soy still services human applications, so not ALL soy planted area would be saved by eliminating animal feed). As an aside, NO, 77% of soy is not grown as animal feed only. In fact, 87% or thereabouts is grown to provide both animal feed AND vegetable oil. Of that 86%, about 20% by weight is oil and 80% by weight is meal. The 77% refers to a "by weight" analysis.

So, if we have 1.6 billion Ha under crops and 540 million Ha are used for feed, then around 1 billion Ha are used for human applications. I would discount slightly the area for feed on the basis of what I said about soy - it is classified as feed yet most is used for human applications. If we eliminated the feed market, how much soy would still be needed? We currently have about 100 million Ha of soy, so even if we reduced this by 2/3, it still leaves about 30 million Ha, so total feed use is closer to 520 million Ha. This bumps the total used for human applications up closer to 1.1 billion Ha. If you disagree you need to offer an alternative analysis.

Our World in Data states that about 740 million hectares are used for human food; they got this from Poore & Nemecek (2018).

https://ourworldindata.org/uploads/2021/03/Land-use-of-different-diets-Poore-Nemecek-2048x1259.png

We should add our 30 million Ha for soy to this, giving us a total of about 770 million Ha for human food. This suggests that cropland area for other than food and feed is about 330 million Ha (1.1 billion less 770 million). I think it is safe to conclude therefore that currently about 330 million hectares are used for non-food applications.

Now we have a baseline, how much crop do we need to replace animals in our diet? Here we have a couple of references which give us some estimates for land use for a vegan diet.

The first is from the Australian CSIRO which estimates that globally, we shouldn't use more than about two billion hectares to grow crops. Currently, we use about 1.6 billion (and possibly more).

News and articles

Discover the latest in science and innovation with our news stories and media releases.

blog.csiro.au

CSIRO reports that the average Australian uses about .25/Ha of cropland, including animal feed crops. An Australian pursuing a healthy and sustainable diet might reduce this to about .15/Ha of cropland.

The second paper offers a detailed analysis of the opportunity cost of animal foods compared to plant foods and concludes a plant-based system will realise multiple benefits, including a reduction in land area used for agriculture. More useful however is their estimate that a vegan diet would require about .12/Ha of cropland per person in the US. This estimate as far as I can tell is based on a diet that doesn't significantly reduce calories over the standard US diet so it is possible that a healthy vegan diet might use less.

https://www.pnas.org/doi/10.1073/pnas.1713820115

In a rough analysis I conducted a couple of years ago, I concluded that a vegan diet would require about .18/Ha of cropland, interestingly somewhere in the middle of the range of values here. The point is that an average diet right now requires about .1/Ha of cropland for fruit and vegetables, while I have estimated that an additional .08/Ha is required to replace meat and dairy. Given the estimates in these papers, the correct value is somewhere closer to about .02-.05/Ha. Let's go for the lower value of .02/Ha.

8 billion people needing .02/Ha gives us about 160 million Ha.

So, adding this all together. 770 million Ha for human crop food right now, an additional 160 million Ha to replace meat and dairy, plus about 330 million Ha for non-food human applications, gives us a total of around 1.26 billion Ha. Note that this does NOT include any land needed to grow plants to replace other animal product applications (eg leather, wool). So there is likely to be a little more again. Plus, is there allowance for crop failures and so on due to increasing climate volatility? I am not sure, but I am willing to bet we should add a bit more to this. So we have a solid estimate of 1.2-1.3 billion hectares, with potential for this to be closer to 1.3-1.5 billion Ha.

Of course we can also do a direct calculation using the vegan diet footprint from the Shepon paper; that is .12/Ha x 8 billion people which returns about 960 million hectares, add on the 330 million hectares for non-food use and we get 1.260 billion hectares. This is very close to my estimate above, but without seeing how Shepon et al came up with their value, I am inclined to suspect they haven't allowed for a variety of uncertainties. But taken all together, It still turns out that we are going to need somewhere around 1.3 billion hectares and probably a little more.

Not a big reduction in cropland overall. Plus, this area must grow as population increases. Of course, other methods of food production may change this picture substantially (eg precision fermentation of meat/dairy analogs, vertical farming).

My proposition then remains. If we magically replaced tomorrow all animal use by humans for food, fibre etc with plants and maintained the global population with a healthy and sustainable plant-based diet, land area under crops would not decrease by a significant margin. I think it would decrease, but not by as much as people think.

 

[Graeme M]

Your arguments don't add up. You say animal farming can be good for the land, yet you don't expand on how.
Your argument that converting land used for animals to land used for plants for human consumption would require vast numbers of animals killed --land used for animals bred for human food requires vast numbers of wildlife killed off.
As it's been continually pointed out, raising animals for food requires 6 x's the feed that has to be grown elsewhere to feed the animals fed to people. Your insistence that eliminating animals and replacing replacing them with crops wouldn't save much of the croplands doesn't add up. Eliminate the animals and you eliminate the need for as much cropland.
You completely miss the amount of water used for animals, both for their own consumption, and for the cleaning. You don't mention what happens to the animals waste products

Silva, most of your comment is misleading. I am not inclined to go into depth, but think about the best we can do with either option. Croplands are not good solutions for food overall - less biodiversity, the need for intensive artificial inputs, the killing of vast numbers of animals (primarily invertebrates) and so on. There is little we can do to improve this. On the other hand, animals *can* be farmed in ways that are net beneficial to the landscape - we don't *have* to use feedlots or CAFOs. When I visit my friends beef and sheep farm, I observe good soils, trees and natural grasses, minimal environmental intrusion and the use of non-human edible food to produce human-edible food. When I visit my other friend's sugar cane farm, I see the complete opposite.

In this regard, consider using natural pasture grazed ruminants for some proportion of global protein (remember that while animals provide only 18% of calories, they provide nearly 40% of protein). If we stick with the 740 million Ha Nemecek & Poore claim is currently used for human food, and topped up calories/protein with grazed ruminants, how much cropland would we need for feed? I do not know, but I am willing to bet it isn't 550 million ha (most of which goes to CAFO system monogastrics). My best guess? About 100-150 million ha. Giving us a total area under crops of some 900 million Ha. Add on the 330 million ha for non-food related uses, and we have about 1.23 million Ha. This *might* be better in the longer run.

 

[Vai101]

The large scale monocropping of plants for a plant-based diet can have several potential impacts, both positive and negative. On the positive side, it can increase food production and security by allowing large-scale production of certain foods, potentially helping to reduce world hunger. However, this kind of agriculture can also reduce biodiversity, as only one or two species of plants will be grown on a large scale, as well as increasing the risk of agricultural pests and diseases. Additionally, there is potential for soil erosion and contamination from the use of fertilizers and pesticides.

 

[David3]

The large scale monocropping of plants for a plant-based diet can have several potential impacts, both positive and negative. On the positive side, it can increase food production and security by allowing large-scale production of certain foods, potentially helping to reduce world hunger. However, this kind of agriculture can also reduce biodiversity, as only one or two species of plants will be grown on a large scale, as well as increasing the risk of agricultural pests and diseases. Additionally, there is potential for soil erosion and contamination from the use of fertilizers and pesticides.

.
The large-scale monocropping of plants for livestock feed is even worse.

Per the U.S. Department of Agriculture, one-third of the U.S. corn crop is used for animal feed, one-third is used to make ethanol fuel, and the remaining third of the U.S. corn crop is used for a combination of industrial uses, beverages (high fructose corn sweetener), human food, and for export: Corn is America’s Largest Crop in 2019

Per the U.S. Department of Agriculture, 70% of the U.S. soybean crop is used for animal feed: https://www.usda.gov/sites/default/files/documents/coexistence-soybeans-factsheet.pdf

 

[Lou]

I'm not anyone has mentioned this yet but there is also a social economic price to pay. Maybe the best example is the 'food desserts" created in Middle America with corn. Because of a number of economic factors the only way corn farmers can make a living is by growing more corn. This creates a landscape where every available square foot is dedicated to corn production. in these areas, a little more than 50 years ago farmers had gardens and orchards too. Now despite being surrounded by farm land the local market has to import produce from other states or countries.