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  • Writer's pictureNicholas Carter

The Eco Story of the Humble Soybean

Updated: Dec 6, 2023

Exploring Soy's Environmental Impacts and Solutions

Few food subjects spark as much debate as soy. The story of soy weaves a complex tapestry of environmental considerations. This is a tale of contrasts, where soy's benefits are intertwined with its challenges in its dominant pesticide heavy intensive use to feed farmed animals.

In this review, we dig deep into soy's environmental impact. Does it truly champion eco-friendliness in our quest for planetary health and food security? Let's find out.

DALL·E 3 AI Image generated using a prompt of an eco-friendly soy farm with wood chips, renewables, and rewilded landscape.

Article Contents:

Origin story of soy

The precise beginnings of the soybean is commonly associated with its origin in North-eastern China around 1100 BCE. Some research states it was domesticated from wild soybean Glycine soja (Sieb. & Zucc.) in East Asia 6000-9000 years ago. Historical records from China attribute great significance to the soybean as a pivotal legume and one of the five revered grains, including rice, soybean, wheat, barley, and millet, which collectively formed the bedrock of Chinese civilization's sustenance. Other records suggest soy was being grown in both Korea and Japan around 5,500 years ago.

Soybeans as depected in Japanese texts sourced from Leiden University Libraries digital collections

Soybeans origins were primarily used for ecological restoration as a rotation crop to improve soil fertility then later for its nutritional components. Soybean cultivation began to expand globally during the 18th and 19th centuries, estimated to arrive in North America in 1765 where it became a crucial crop due to its high protein content and various industrial uses, such as soybean oil production.

Soy by the numbers

Some may imagine the below now when they think of soy. This narrative is used as an anti-industrial agriculture visual, often attacking plant-based foods for human consumption.

But where does all this soy go?

Image sourced from SEI of a mass soybean harvesting for animal feedcrops in Campo Verde, Mato Grosso, Brazil. Photo: alffoto / Getty Images Plus.

It is almost entirely destined for the animal agriculture industry, mostly for chickens and pigs in confinement.

  • 76% of soy globally is used as animal feed (37% of which is solely for chicken)

  • 6% of soy is for human consumption (mostly organically grown)

  • 90% of soybean crops grown in the US are feed for farmed animals

  • 95% of Brazilian soy (the country now producing the most soy) is used for animal feed.

The area sown with soybean alone has more than doubled since 1990. It is now three times the size of Germany.

Is soy good for the environment?

Soy has remarkable potential to alleviate deforestation, increase food security, lower greenhouse gas emissions (GHG), and address key environmental issues. Soybeans hold the distinction of being the most abundant protein source among leguminous crops and pulses (at ~43% protein depending on the subtype and variety). This has resulted in it being the go-to crop to quickly grow confined farmed animals to produce meat and dairy. As such, soy is a major driver of deforestation (although still a distant second behind beef). This has created a stigma likely pushing consumers away from tofu, tempeh, soy milk, and other soy products. We have an abundance of data on the scientific realities of soy and its environmental benefits. Yet it's been a victim to significant environmental and nutritional misinformation campaigns paired with dairy industry supported studies amplifying this uncertainty, casting doubt, and delaying positive changes towards healthy, planetary health promoting plant proteins like soy.

Recent meta-analyses have made this absolutely clear in the scientific literature that soy products for human consumption, like tofu, tempeh, edamame, etc. are among the lowest impacts foods to produce and consume:

Images sourced from BBC via study by Poore & Nemecek, 2018

Images sourced from Poore & Nemecek, 2018

What about soy milk?

Cow's milk demonstrates substantially greater impacts compared to its plant-based counterparts across all metrics. Based on a meta-analysis of almost 40,000 farms covering data from 119 different countries, research by Poore & Nemecek (2018) showed that dairy generates approximately threefold higher greenhouse gas emissions, occupies approximately ten times more land, consumes two to twenty times more freshwater, and gives rise to significantly elevated levels of eutrophication (excessive nutrient runoff into waterways).

Sourced from Our World in Data

The environmental footprints of types of milk per 100 grams of protein would show soy is the best in each category.

For individuals seeking to diminish the environmental footprint of their dietary choices, transitioning to soy-milk, that can be made from scratch without tetra packs and plastic waste, offers a commendable strategy. It would be wise to add calcium and supplement B12, which can be done with easy fortification.

Yield benefits

Soybeans exhibit remarkable efficiency in protein and calorie production per acre according to an original analysis showing they lead in protein yield with 513,066 g/acre, outperforming even the most productive animal source, chicken, which only yields 163,212 g/acre. This signifies a substantial 214% advantage in protein output. Soybeans also excel in calorie production, yielding 6,271,268 g/acre, a remarkable 319% more than chicken on a per acre basis.

More published research is needed to further outline the varying estimates in the literature, but this is generally the reason why the animal agriculture industry uses soy more than any other crop to quickly grow farm animals.

Where is the majority of soy now grown?

Brazil, Argentina, and the United States (US) are the three largest soy producers in the world, accounting for about 81% of global soy production (as of 2021). The US has been a major player in soy production since the 1940s, but South America’s share has grown significantly in recent years. Brazil, Argentina, and Paraguay alone were responsible for 52% of global soy production in 2021, up from less than 3% in the 1960s. And in 2019, Brazil officially became the world’s largest soy producer.

From 2000 to 2017, only a quarter of the soy produced in South America was used domestically. The rest was exported to other countries. In 2021, the EU and China were the largest importers of South American soy, taking 11.3% and 33.6% of total production, respectively (FAO Stat).

95% of Brazilian soy (the country now producing the most soy) is used for animal feed. More than 75% of soy (by weight) globally is used for animal feed. 37% of global soy is fed to chickens and other poultry, one-fifth to pigs; 6% for farmed fish, and only about 2% for beef and dairy production.

The drive for more soy production is a story centered around our global food system incentivizing animal agriculture, and particularly shifting towards more consumption of chicken. Global meat production and per capita has quadrupled over the last 50 years, particularly chicken - the largest consumer of soy feed.

Only 6% of global soy output is used for human consumption. 81% of soy processing is in the form of cake. 99% of that goes to farmed animals.

A Diagram shows the estimated usage of soybeans and their derivatives by weight. The percentages in the diagram are based on data from the USDA for 2018-2019 and expert estimations from the United Soybean Board (USB) for 2017-2018. The use of soy oil for biodiesel was calculated by combining estimations from the USB with data from USDA biofuel annuals. This figure was produced by TABLE.

What drives soy to be planted?

The increase in soy production has mainly been due to the growing demand for soy cake, which is used as animal feed.

This is because of the increasing demand for animal-based products. However, both soy oil and soy cake come from the same bean, so the rapid growth in the use of soy for feed has also been helped by the increasing demand for soy-based vegetable oil and biofuel.

"An argument could be made, however, that increases in the production of soy have primarily been driven not by the demand for animal feed, but by the demand for soy oil for human consumption. One might view soy cake as only a by-product of the production of soy oil, as its economic value is much lower (a kilogram of soy oil is about twice the value of a kilogram of soy cake). However, since the crushing of soybeans produces much less oil (20% by weight) than cake (80%), only a third of the overall value of a kilogram crushed soybeans is derived from the oil, as compared with two thirds from the cake. Soy oil is also one of the cheapest vegetable oils on the commodity market, whereas soy cake is the most valuable of all oilseed cakes due to its favourable amino acid profile and the low levels of anti-nutritive compounds it contains after heat treatment. It is therefore likely that the growth in soy production has primarily been driven by the demand of soy cake for feed, and hence by the growing demand for animal-based products.” Report: Soy: food, feed, and land use change.

While both components have value, when it comes to what provides farmers the most value and economic livelihood, it is the component that feeds confined animals that drives profitability, partly driven by disproportionate global subsidization of animal agriculture.

The amount of US & EU public money supporting plant-based alternatives (all, not just soy-based) is 0.1% of what props up animal agriculture and there’s 190 times the lobbying expenditure for animal agriculture in the US, according to a recent analysis. This has resulted in many US farmers in particular feeling trapped and unable to escapate the soy for feedcrop commodity cycle, one that mostly benefits big animal agribusiness, not small farmers.

Chicken, Soy, and Biodiversity Loss

Soy and chicken are linked. What people perceive as an issue with the environmental impacts of soy is largely a chicken issue. The issue is that we funnel a huge amount of crops through animals, at only about a 10% conversion rate of crop calories to meat. It’s often grown in monocultures with little care for soil erosion or quality of the plant, but instead simply as a mass commodity.

For every 100 calories of crops, like soy or grains, fed to chickens, people only receive about 12 calories of chicken meat. That’s almost a 90% loss, which happens because of course these are functioning living animals. The protein conversion is equally dismal with a 60% loss. Perhaps an even bigger reason to opt for soy plant proteins instead of chicken is when one widens the lens to consider increased risks of zoonotic diseases and antibiotic-resistant bacteria. Continuing to farm chicken is one of the riskiest ways of attempting to feed the world.

This needs to change, as the biomass of poultry globally is three times that of ALL wild bird species and is a major driver of biodiversity loss, largely due to increase demand for soy feed crops. ​

A significant proportion of China's farmed animal production relies on soy-protein feedstock sourced from Brazil, primarily the Cerrado. China's annual soy imports from Brazil witnessed a remarkable increase, escalating from zero in 1996 to approximately 7,000,000 tons merely a decade later. In 2003, China's soybean imports surged to an astonishing 21,000,000 tons, constituting 10% of the global soybean production and marking an 83% increase compared to 2002. Notably, a substantial portion, 29%, of these soy imports originated from Brazil. To facilitate these imports, approximately 4,000,000 hectares of Brazilian cropland are dedicated to soybean production destined for China's livestock feed industry.

“Substituting soy for meat as a source of protein for humans would reduce total biomass appropriation in 2050 by 94% below 2000 baseline levels” Machovina, Feeley, & Ripple, 2015

When comparing the land area required for protein production, it’s evident that soybeans are a substantially more efficient protein source compared to meat. The area needed to produce 1 kilogram of protein from soybeans stands at a modest 12 square meters. In stark contrast, the land area required for common cuts of meat production reveals a stark disparity: chicken necessitates 3 times more area at 39 square meters, pork demands 9 times more at 107 square meters, and beef commands a staggering 32 times more area at 377 square meters.

DALL·E 3 AI Image generated a prompt asking for an image of whole soy foods including soy milk, edamame, soy curls, white miso paste, soy sauce. tempeh, textured vegetable protein, soy nuts and firm tofu.

Degenerative vs. Regenerative Soy

The introduction of a new type of soybean in 1996 made it easier to grow soy in areas that were previously difficult to cultivate. This new soybean was able to tolerate a common herbicide, glyphosate, which meant that farmers could use less labor and machinery to control weeds. Since 1990, the global use of pesticides has doubled, reaching a yearly application of over 4 million tons of active components used for managing weeds, insects, and various plant pests. This came with a host of issues, especially for those exposed to them frequently. But as a result, soy production was able to expand into areas with high levels of native vegetation or weeds. This has been an important development in the history of soy production, but also is often exaggerated in its benefits since it isn’t the only way in which it can be mass grown.

Compared to Brazil where 94% of soy crop is genetically modified (GM) for glyphosate weed control, the EU has strict regulations governing GM soy for direct human consumption. A substantial portion of the soy consumed in Europe originates from European production. The good news? Soy yields exhibit a similarity between the EU and Brazil, with France yielding 3 tonnes per hectare in contrast to Brazil's 2.9 tonnes. Interestingly, certain EU nations achieve even higher yields, such as Spain (3.3 tonnes) and Italy (4 tonnes).

How can soy be grown better? Being a legume, it has the ability to biologically fix its own nitrogen, grow in poor quality soils, and rely on very little fertilizer or manure inputs. On average, 68% of the plant's nitrogen can be derived from symbiotic nitrogen fixation. There’s also other more natural ways to manage weeds and grow in full stock-free organic settings, which should be incentivized.

Intercropping soybeans is a the restorative practice of planting two crops together. One can plant soybeans among small grains or using different combinations like ryegrass or clover with soybeans. Introducing grasses or legume-grass mixtures into soybean fields during specific growth stages can reduce erosion and offer winter ground cover, eventually enriching the soil in the following spring.

These regenerative ways to grow soy without synthetic fertilizers, manure, or herbicides still provide back a massive amount of protein and nutrients per acre, while freeing up a major amount of land back for rewilding and biodiversity. They would require more labour though and smaller farms, in some cases possibly hurting yields, but worthwhile exploring for the major tradeoff benefits.

Stock image of soybean farm in Wisconsin.


Government Action

  • Allow soy milk as a reimbursable milk alternative option in free and reduced school lunch programs. This program, as proposed in the United States, allows schools to get reimbursed by the federal government for free meals for underpriviledged kids in schools. The dairy industry relies heavily on school lunch programs but if you want to offer soy milk in school, one doesn't get reimbursed. Many have called out this as racist since racialized individuals have a higher rate of lactose intolerance. USDA has already admitted soy milk is a nutritionally adequate alternative, but still doesn't offer reimbusent.

  • The Brazilian government and almost all Brazilian soy traders, who together account for 90% of soy exports, have signed the Soy Moratorium. The goal of this agreement is to prevent further loss of native vegetation in the Brazilian Amazon.

  • Mighty Earth has intensified pressure on Cargill's commitment to finally halt ecosystem destruction linked to soy and other commodities in Brazil, Argentina, and Uruguay by 2025. There is still a limited scope to the pledge and arbitrary exclusion of other at-risk areas like Bolivia, Paraguay, and Colombia, where Cargill's operations contribute to substantial deforestation.

  • The EU Deforestation-Free supply chain regulation could improve accountability and could reduce soy feed crop production. However, it currently exempts recently deforested pastureland converted to soy cropland, and the biodiverse Cerrado savanna in Brazil, the biggest producers of soy.

New technologies

  • Trase Earth is better tracking key areas like the Amazon and Cerrado biomes of Brazil where 40% (1.8 Mha) and 20% (3.5 Mha) of the areas where soy was grown in 2015, had been under native vegetation in 2000. This is a significant reduction in not only carbon drawdown, but also biodiversity, the vast majority driven by increased need to feed confined animals feeding the majority of the world’s meat consumption.

  • According to Brazil’s space agency, INPE, the overall rate of deforestation in the Brazilian Amazon has decreased to about a third of what it was before the Soy Moratorium was implemented. This is a significant reduction and shows the positive impact of the Moratorium on preserving native vegetation in the Brazilian Amazon. Funding for this though has jeopardized monitoring some areas. The moratorium also unfortunately does not prevent conversion of pasture land that had been cleared prior to the July 2008 cut-off, which makes little sense.

Image sourced from Trase of a soy feedcrop plantation // Marizilda Cruppe

Consumer Campaigns

  • Beans is How campaign, which focuses on doubling global bean consumption by 2028 (including soy, peas, lentils and other pulses, and legumes), and as reported by Green Queen, beans are cheap, long-lasting, nutrient-dense, versatile, planet-friendly, and ubiquitous, and are being rebranded.

  • Better show that the impacts of soy are due to animal agriculture. Soy is a high-protein, high-energy crop and will continue to be used to grow animals quickly, unless to switch it to improve food security and planetary health.

Ultimately, this makes the case that soy is an environmental solution. However, we should still be striving to diversify the mix of plant proteins produced to increase resilience to the planet and our health.


Soybeans are a major global crop with significant environmental impacts. Soy is only behind beef as the leading cause of deforestation in the Amazon. This is commonly used in arguments against plant-based diets and soy foods. However, 76% of global soy production is used for animal feed, and only 6% is used for human consumption as a protein food, most of which is organically grown.

Compared to dairy, soy milk uses one-tenth of the land, produces one-third of the greenhouse gases, and consumes half to one-twentieth of the freshwater. Embracing soy for protein means using significantly less land compared to chicken, pork, or beef: 3x less for chicken, 9x less for pork, and a staggering 32x less for beef per kilogram of protein. Choosing to swap meat and dairy for soy-based options like tofu, tempeh, and soy milk is choosing to free up land, biodiversity, water, and to enhance overall planetary health.


Featured Report: “Soy: Food, Feed, and Land Use Change” (summary) aims to illuminate key debates surrounding and linked to soy, land use change and animal- versus plant-based protein.

Explainer: Soy (Our World in Data)

Learn more at:

DALL·E 3 AI Image generated using a prompt of a lush solarpunk futuristic windfarm soybean farm that restores nature and sells whole plant foods from a modern market stand with a green roof.

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