Early in the morning, a tractor arrives at the edge of a field and starts to make its way across the vast stretch of land. This farm, like so many others, is filled with row upon row of soybeans, the fourth most widely farmed crop in the world by both land area and value.
Global demand for soybeans has soared in recent years, largely due to the popularity of this legume as a source of protein in animal feed. The world now produces over 13 times more soy than it did in the early 1960s. While this might be good for the soy industry, it comes at a great cost to the environment.
Brazil, the world’s leading soybean producer, harvests 133 million tonnes of soy per year, followed by the U.S. at 117 million tonnes. Most of the world’s soy is farmed in these two countries. The crop is also grown in Argentina, China, India, Paraguay, and various other places around the globe.
In South America, where the area of land used to grow soy more than doubled between 2000 and 2019, soybeans are commonly grown on former cattle pastures. Because buying land that has previously been cleared by beef producers pushes cattle ranching further into forest areas, soy farms play a key role in driving deforestation. Soy farms have invaded the Amazon rainforest, Argentina’s Chaco dry forest, Paraguay’s Atlantic Forest, Bolivia’s Chiquitania forest, Uruguay’s Campos grasslands, and Brazil’s Cerrado savanna.
More than 81 percent of soybean-producing land in the U.S. is found in the northern Midwest, where higher crop yields allow soybeans to be grown relatively cheaply. In 2020, around 35 percent of national soybean production came from just three states: Illinois, Iowa, and Minnesota. Agricultural expansion for soybean production in the Midwest has destroyed vast swathes of tallgrass prairies.
According to the 2017 USDA Census of Agriculture, more than 300,000 farms in the U.S produce soybeans. Of these, close to 19,500 farms devote at least 1,000 acres to soy, with the largest soy crops stretching across more than 5,000 acres of land.
While most soybean producers are small, a minority of large producers dominate the sector. In 2012, farms covering less than 250 acres—around 70 percent of soy farms—accounted for only 23 percent of the year’s soybean crop.
Some people mistakenly blame the high demand for soy on foods such as tofu, tempeh, edamame beans, and soy milk, but the real culprit is factory-farmed meat. Globally, a total of just 19.2 percent of soy goes to food for humans, almost two-thirds of which is turned into oil, while 77 percent is used to feed farmed animals, primarily chickens and pigs.
Poultry production is the world’s single biggest consumer of soy, with chickens and other domestic fowl gobbling up 37 percent of the total amount of soy produced. Although it is not naturally a part of their diet, farmed birds, especially those in intensive systems, are fed soy because it is high in protein and promotes growth.
When grown directly for human consumption, soy can be a relatively sustainable source of nutritious plant protein, but the scale on which it is produced to feed farmed animals and the intensive farming practices used harm the environment in numerous ways. Soybeans are typically grown in rotation with corn, or in monoculture systems (where soy is the only crop planted). While this way of farming can make the land more productive (at least in the short term), it also damages vital natural resources such as soil and water and emits significant quantities of greenhouse gases.
One of several problems with intensive soy farms is their use of agrochemicals. The lack of biodiversity in soy plantations makes the crops more prone to disease and more attractive to insects, leading to the increased use of pesticides. Most soybeans grown in the U.S. are genetically modified (GM) to be herbicide-tolerant (HT) so that they can survive being sprayed with high concentrations of these chemicals, allowing for even more environmental damage.
According to the results of the 2020 Agricultural Chemical Use Survey, conducted by the National Agricultural Statistics Service (NASS), herbicides were applied to 98 percent of U.S. land used for soybean cultivation. 22 percent of the land was treated with fungicides, and 20 percent with insecticides.
Fertile soil is essential for growing food, but in many parts of the world, the health of this vital material is rapidly deteriorating. While soil naturally erodes and degrades over time, agricultural activity, such as the constant plowing of land for crop cultivation, accelerates this process. Over the past 150 years, the world has lost half of its topsoil.
Iowa, for example, is home to some of the world’s most fertile loam topsoil, but the 20th century saw the state’s average depth of topsoil decrease from approximately 14-18 inches to just 6-8 inches. A 2010 study of soil quality in Iowa’s croplands found that in just 50 years, the soil had lost organic matter, become more acidic, and its structure had degraded.
Soy plantations typically cover huge areas of land, and bigger farms typically mean bigger equipment. Heavy farm vehicles and machinery are leading causes of soil compaction. Loosening compacted soil for planting often uses more tillage operations than normal, which harms the soil’s structure and makes the ground more prone to becoming compacted again. Compacted soil is lower in quality and less productive.
When soil becomes less fertile as a result of conventional farming practices, more fertilizer is then needed to help plants to grow. In 2020 alone, soybean production in the U.S. used more than 3 billion pounds of potash, nearly 2 billion pounds of phosphate, around 450 million pounds of nitrogen, and 138 million pounds of sulfur.
The negative impacts of soy farms on soil impacts water quality of nearby rivers and streams. Soil erosion leads to water pollution when rain washes loose soil particles, or sediment, into waterways, turning the water murky and making it harder for sunlight to get through, which depletes the water of oxygen.
Agrochemicals are another key source of water pollution. Pesticides and fertilizers applied to soybean fields in huge quantities enter surface water through agricultural runoff or seep through the soil into the groundwater underneath, leading to dead zones in oceans.
Soy farming also consumes a lot of water. Of all the freshwater that was taken from ground or surface water sources in the U.S. in 2015, 42 percent went to crop irrigation (the controlled watering of plants using artificial systems such as pipes and sprinklers). Soybeans are one of the nation’s most irrigated crops, second only to corn.
While the majority of soy farms are able to depend on rainwater, more than 8,300 farms in the U.S. irrigated all of their soybean crops in 2017 and almost 16,600 irrigated some of their soybean crops. Overall, more than 9 million acres of land were irrigated for soybean production.
Of the 8.1 gigatonnes of carbon dioxide equivalent (CO2-eq) greenhouse gas (GHG) emissions released into the atmosphere each year by animal agriculture, an estimated 41 percent (3.3 gigatonnes CO2-eq) comes from the production of animal feed, in which soy is a common ingredient. From the clearing of native vegetation for agricultural expansion to the processing and transportation of animal feed, every stage of soybean production emits greenhouse gases.
Land-use change, energy consumption, and soil disturbance are three key sources of soy farm emissions. As a result, the carbon footprint of soy varies widely depending on how and where it is grown. A life-cycle analysis of the global warming potential of soybeans grown in U.S. Midwestern counties calculated that in areas where soy cultivation had the highest environmental impact, up to 22 kilograms of CO2-eq GHG emissions were produced per kilogram of soybeans.
It is worth noting, however, that eating soy directly has a far lower environmental impact than eating animals who have been fed soy. Data from a meta-analysis of global food production shows that, on average, 1.98 kilograms of CO2-eq emissions are emitted per 100 grams of protein from tofu. While that might sound like a lot, animal products, by comparison, emit between 4.21 and 49.89 kilograms of CO2-eq emissions per 100 grams of protein, with beef on the highest end.
Like many other intensive farms, soy farms not only harm the environment but also have numerous social impacts, especially on rural communities. While soybean production can boost economic growth, it can also increase income inequality and affect human health via water pollution and occupational hazards. This kind of large-scale agriculture for export can also leave agricultural workers with less security and freedom of choice than other forms of farming, especially when compared to farming based on secure land tenure.
Smallholder farmers are often pressured into selling their land over to soybean production. In some cases, mainly in South America, soy estates threaten, violently attack, and steal land from Indigenous peoples.
People who live near or work in soybean fields are exposed to hazardous chemicals, many of which can lead to chronic health issues in humans. An incident in Brazil in 2013 saw around 90 people hospitalized when an airplane spraying pesticides in nearby fields of soybeans and corn flew over a school. Many residents in exposed areas have reported that they have symptoms of pesticide poisoning.
The intensive way that soy is currently farmed is the main reason why it is bad for the environment. The driving force behind the increasing global demand for soy and its negative effects on the planet is the mass consumption of meat. Directly consuming soy by eating foods such as tofu and tempeh as part of a healthy and balanced plant-based diet can help to lessen the negative impacts of our food system, including its contribution to climate change.