Breaking Ground

In 2009, Philip Hunke, a Ph.D. candidate at the University of Potsdam in Germany, was pondering topics for a dissertation on soil erosion and degradation when his adviser suggested he look at Brazil. A specialist in hydrology, or the study of the movement of water over land, Hunke began by looking at the country’s deforestation rate. Countless researchers had published their findings on the reasons and consequences of deforestation in the Amazon rainforest. But as he looked at the numbers, Hunke was surprised to find that the Amazon’s deforestation rate had been overtaken by that of another, less celebrated biome: a grassland in the center of Brazil, called the Cerrado. When Hunke looked at the state of Mato Grosso in Brazil’s center-west, he could see why: What had once been part of the savannah was now agriculture. The only natural vegetation that was left was hugging the streams. Intensive agriculture – the kind that depends on large doses of chemical fertilizer and heavy machinery – has long been connected to the destruction of soil. But when he looked for data on the subject, Hunke found that virtually no one had attempted a study of agriculture’s impact on the region’s soils.

From China to the American Midwest, the world’s soil – the foundation for more than 99 percent of humanity’s food supply – is becoming a scarcer resource. There are two faces of this slow-motion catastrophe: one is degradation, or the destruction of the biological and mineral properties which give soil life and allow plants to grow from it. The other is erosion, where soil that has been made physically weak blows away in the wind or washes away in the rain. By one estimate, the world loses 10 hectares of cropland – equivalent to 10 million FIFA soccer fields – every year to erosion. And as the world’s population grows and becomes wealthier, demanding more meat fed with crops like corn and soy, the stress to the world’s soil is becoming harder to ignore.

Faced with the global destruction of the world’s soil, humanity has two options, says David Montgomery, author of Dirt: The Erosion of Civilizations and the forthcoming Hidden Half of Nature: grow more food on the land we already farm, or convert new land to farming. But farming is not just a hapless victim. The chemically intensive, highly mechanized ways we’ve used to increase our food supply in the past are usually the cause of soil’s destruction in the first place. On the other hand, expanding into new areas would mean converting areas like rainforests and grasslands to agriculture – areas that breathe and store carbon and fill the earth with oxygen. Making farmland out of these areas comes at the cost of losing an irreplaceable natural resource and a hedge against climate change. If we mistreat it, we set ourselves up to repeat the problems of the past.

This is why, if you want to know about the future of farming and food, it helps to consider the soil that is anchoring one of the newest and largest agricultural corridors on earth. In two generations, Brazil has transformed the Cerrado into one of the major soy producing regions of the world. Soy is an essential feed for pigs, and with a growing appetite for pork, China is the Cerrado’s largest customer. Feeding China has been an incredible business opportunity for Brazilian farmers. But as soy plantations blanket the region to feed that demand, they are also laying waste to the Cerrado’s soils.

If the Brazil-China corridor is an example of the global food system’s agility – its ability to leverage the natural resources of one country for another’s benefit, ensuring that China’s demand for food is not limited to what it can produce on its own soil – it is also an example of how the problems with growing food transcend national boundaries. The Cerrado may be in Brazil, but the roots of its problems extend to the far side of the world.

THE CORRIDOR

In the history of Chinese agriculture, the period known as the “reform era” spanning the 1970s and 1980s stands out as a particularly stressful time. For decades, the government had insisted on self-reliance in grain and soy, but as the economy opened up and an increasingly wealthy population consumed more food, Chinese farmers were pushing the nation’s soil to its limits. To increase yields, farmers applied ever-larger amounts of fertilizer, overwhelming the soil biology and causing it to degrade. To expand their fields, farmers cut down forests to cultivate the soils under the trees, and fertilized, planted, and plowed nutrient-poor lands to the point that the soil there could no longer grow anything. As eroded soil washed away, it clogged irrigation systems, making it harder to grow anything, even on those areas where the soil was still intact. By the middle of the 1980s, the once reliable increases in yield had hit a ceiling.

According to a 1997 study by Scott Rozelle and Jeremy Veeck of Stanford and Western Michigan Universities, the cost of this catastrophe to China’s grain and soy supply may have been as much as 5.7 million metric tons per year during the late 1980s. At a time when China produced roughly 300 million metric tons of corn, rice, wheat, and soy combined annually, the loss of 5.7 million tons may have been serious, but not so much that the country needed to abandon a policy of self-sufficiency in grain. Through the 1990s and 2000s, China could grow almost all of its own corn, wheat, and rice, and often produced a surplus.

But soy was another matter. Between their deteriorating soils and a growing middle class, Chinese soy farmers could not keep up with demand. In 1995, China bolstered its supply by importing soybeans for the first time. Even though it was still one of the largest producers of soy in the world, domestic production could not keep up with demand. By 2012, China accounted for almost two-thirds of all soy imports in the world. Brazil was its number one supplier.

Why Brazil? The simple answer is that in the Cerrado, Brazil had room to meet the new global demand like no other country did. In the United States (still, to this day, the world’s top producer of soy) farming had reached its geographic limit long ago. In fact, the U.S. had a net loss in agricultural land: almost 9.4 million acres from 1961 to 2012, according to the World Bank. Though the U.S. could export more of its crop to China, there was no new land to cultivate. The Cerrado was ripe for opportunity.

It wasn’t always this way. With its acidic, nutrient-weak soils, the Cerrado has been a desert of economic activity for most of Brazil’s history. When the capital was relocated to the region in 1960, the government had to give away surrounding land to farmers just to bring some in. Then, in the 1970s, Brazilian government scientists developed a few varieties of soy which, paired with a hefty dose of fertilizer and lime, could grow in the harsh tropical soils. Outside Brazil, the discovery was little noticed at first. But once China entered the world market, it took just seven more years for production to double.

As the boom took off, Brazil’s large producers and some foreign agribusiness giants came to the Cerrado, building everything from silos for soy storage, to roads to connect it to the world. Land was cheap, and natural vegetation was constantly being cut down, limed, and made ready for agricultural use, allowing large farms of 40 hectares or more to proliferate. From 2002 to 2012, Brazil increased its agricultural land by an average of 2.4 million acres per year, mostly by clearing the Cerrado. Years after the boom began, a farmer in Mato Grosso could rent an acre for $6, or buy one for $200 — a tenth the rate of the soy-growing regions of the American Midwest. Lured by the bargain, farmers came from all over the world, even from the United States. But more came from Rio Grande do Sul and Paraná, in the agricultural heartland in Southern Brazil.

Saulo Sabino da Cunha, a Brazilian, was one of the incoming farmers. In 2006, when the boom was already underway, he came to Mato Grosso to grow soy and corn, which he sold to some of the big multinationals like Cargill, Bunge, and Louis Dreyfus. Unlike in the South, the terrain was flat here, and with the right soy, the climate was just right for growing.

“In the beginning, everything was really difficult since the technology for the Cerrado was still in development,” he told me. But more money brought in new machinery and chemicals to make growing soy in the converted savannah easier with each passing year. Production grew faster than the infrastructure to move it: After a record 88 million metric ton harvest in 2013, trucks lined up 50 kilometers along the highway to deliver soy to the Port of Santos near Sao Paulo. That year, 75 percent of the country’s soy exports — more than a third of its entire harvest — went to China.

The soy that stays is feeding a growing meat industry: In 2014, Brazil shipped 3.6 million metric tons of chicken and more than half a million metric tons of pork around the globe.

That the agricultural boom had changed the Cerrado’s soils for the worse was undeniable. A few studies had already connected soil erosion to agriculture in parts of the region. But after four decades of agricultural expansion in the region, how badly the biome was threatened was still unknown. Surveying the previous research on the region, Hunke realized no one had connected the various studies to make a comprehensive assessment of the fate of the Cerrado’s soils.

The lack of data reflects a wider lack of interest in the Cerrado, even in Brazil. Though it is one of the most biologically diverse regions in the world, the Cerrado has never enjoyed the romantic appeal of its neighbor, the Amazon rainforest, says Roberto Smeraldi, co-founder and director of Amigos da Terra - Amazônia Brasileira and one of the country’s most prominent environmental activists. Around the world, just mentioning the Amazon invokes images of sky-high trees teeming with life. By contrast, the natural Cerrado looks barren, with a few tangled trees among the grasses. But the surface impression is deceptive. Much of the Cerrado’s life is below the earth — networks of interconnected roots, like an underground forest.

“The difference between the Cerrado and the Amazon is that most of the biomass in Amazonia is above the soil,” Hunke says. “In the Cerrado, it’s a bit like you turn the tree around.”

“So the Amazon is seen as the big thing,” Smeraldi adds, “and the Cerrado, not so much.” That biomass is also a huge carbon store. According to Smeraldi, an acre of Cerrado contains about two-thirds of the carbon of an acre of Amazon.

At the height of the campaign to save the Amazon, Smeraldi says, activists mistakenly assumed the rainforest could be saved without preserving the savannah to its south. Yet the two biomes are closely linked, with the terrain and climate of one blending into the other. In the Cerrado there is a tree, coveted for its wood, called the Pequi. In the Amazon, there is a related species called the Pequia. In some parts of Brazil, you can see both at the same time. Some of the largest rivers feeding the Amazon originate in the Cerrado. As the rainforest’s southern reach has experienced a drop in rainfall in recent years, there is even some evidence that the Cerrado’s transformation is to blame.

Despite their interdependent nature, Brazilian law has followed the logic of the Amazon’s activists and protected the Amazon by cornering it off from the rest of the country. In 2006, under international pressure, soy producers and traders agreed to stop clearing Amazon land for new farms. New soy plantings in the Amazon fell every year thereafter, but with nowhere else to go, farmers expanded their operations in the Cerrado with a newfound zeal. In 2012, the government formalized the Amazon’s protection in law. Activists praised the move, but beyond making clearing land inside the Amazon for farming illegal, the new law also made clearing land outside of it easier, making the Cerrado more necessary to fill the world’s rising demand for soy than ever before.

In 2010, Hunke made the first of several trips to Brazil to gather data himself. Working with master’s students from the Federal University of Mato Grosso, he settled in a farm area near Cuiabá and practiced his Portuguese. There were agricultural workers mixing pesticides, wearing nothing but shorts and flip flops, and farmers living in internet-connected huts in the middle of their fields, monitoring commodity prices through the website of the Chicago Board of Trade.

There was also visible evidence of soil erosion. The team observed ravines hundreds of meters wide and up to ten meters deep – not natural formations, but gullies, formed when the intense rain of the area fell on soil too weak to absorb it, causing massive amounts of the earth to wash away. Hunke started taking samples.

THE NEXUS

What was causing the Cerrado’s erosion? Part of what makes soil erosion in the Cerrado strange is that the primary way Brazilian farmers prepare soil for planting is considered environmentally sound. In many parts of the world, soil erosion is tied to plowing: Driving a metal implement knifelike through the earth loosens the soil and drives weeds underground. Plowing makes farming easier, but it also leaves soil exposed, drying the soil out, killing microorganisms, and making it prone to washing away in the rain, or blowing away in the wind.

Two ways around this problem are to use a “no-till” system, in which farmers plant crops directly into the soil, and to plant a second “cover crop” after a harvest to protect the soil. In the Cerrado, more than 90 percent of cropland is cultivated using no-till systems, and many farmers also plant a cover crop, often a grass. Despite these adaptations, the Cerrado’s soils were deteriorating.

Perhaps the biggest threat to soil is actually one of the fixes farmers applied to make it useable. The Cerrado’s soils are naturally acidic, so farmers coat their land with dolomite for lime at a rate far higher than the rest of Brazil. As the acidity falls, it frees nutrients, without which plants like soy can’t grow. But if you use lime enough, soil will stop clumping, making it less able to hold itself together when stressed by the wind and rain.

In 2014, Hunke and his colleagues in Germany and Brazil published their initial findings from Mato Grosso in the journal Geoderma Regional. By a number of measures, intensive agriculture was harming the soil in Mato Grosso. Citing their own data, the group confirmed a direct link between lime and soil erosion in the Cerrado. Limed soil was weaker than the soil in those areas that were left undisturbed. Though many farmers planted cover crops after a second harvest of soy, the rains were typically most intense between harvests when the soil, already made weak with lime, was left naked under the elements.

Run over repeatedly by tractors and combines, the soil of the Cerrado plantations was also more densely packed than the untouched areas, so that when the rain fell, it collected at the top of the soil, instead of percolating deeper into the ground. Cultivated soil was simply weaker and less able to absorb the typically intense rains of the region. Little wonder, then, that in heavy rains, soil was falling off the land in sheets, as roads became like river beds, carrying dissolved soil, rich with fertilizers and pesticides, into the nearest body of water. While the team observed changes in pastures and sugarcane plantations, “the most pronounced effects have occurred in soybean plots,” they wrote. The local rivers and ponds, meanwhile, were enduring the collective weight of the fertilizers, pesticides, and lime of the Cerrado plantations. In some cases, the team found that pesticides in water exceeded Brazil’s own legal limits.

The future was not encouraging. In another paper that year, Hunke and the team synthesized findings from 80 soil and sixteen water studies on different parts of the Cerrado. The low stability they had observed in Mato Grosso had been observed by other researchers all over the Cerrado. As land became scarcer, farmers would likely move further north, where soils were sandier, less stable, less fertile, and the rate of erosion would accelerate. The expansion of intensive agriculture “is likely to seriously limit the Cerrado’s future regarding both agricultural productivity and ecosystem stability,” they wrote. In feeding China, Brazil was turning an irreplaceable biome into a farm, and now the farm itself was under threat.

THE GLOBAL GOOD OF SOIL

There is an argument that, managed carefully, and kept inside some geographic limit, high fertilizer, chemical-intensive farming is actually the compromise needed to keep agriculture from taking over all the world’s grasslands and forests. But simply expanding agricultural land alone won’t solve these problems. It could just bring those problems to new areas.

“Once we’re farming everywhere in the world that could be farmed productively, we still have to figure out how to do that in perpetuity,” Montgomery says. “Say we expand everywhere. We’re still going to have the same problem, just later, if we use agricultural methods that degrade the soil.”

Da Cunha, the Mato Grosso soy farmer, says he believes some kind of change is imminent. If we do not make it ourselves, the environment may force it upon us. “In my opinion, the entire agricultural system lives in a big paradox,” he says. “At a time we need to produce more and more food for a world population that does not stop growing, we also need to think of our increasingly scarce natural resources… I believe we have to rethink the way we farm, live, and feed ourselves.”

For the Cerrado’s conversion from grassland to farmland, there have been some substantial benefits: more soy and more meat for the world, more opportunities for farmers from Rio Grande do Sul to Iowa and the companies that supply them. How evenly the wealth of the soy industry is distributed is still controversial: A 2012 study of Amazonian soy found that the industry added huge wealth to the region, but that it was mostly captured by the large farmers who dominated production.

Today, Brazil depends heavily on soy for export earnings. Brazilian soy is also more necessary to China than ever before. The Chinese middle class – now more than twice the size of the entire US population – is undoubtedly the driving force behind surging demand. But environmental degradation has made it increasingly difficult for Chinese farmers to contribute to the national supply. Less than ten years after peaking in 2004, China lost more than 31 million acres of farmland. About 40 percent of the remaining soils are seriously eroded, degraded, and polluted with industrial chemicals. China can still produce almost all of its own corn, wheat, and rice, but in the next ten years, whether the loss of land will progress further and force it to source those grains from elsewhere, or whether yield will grow with demand, is not yet clear. For the foreseeable future, the Cerrado will continue to be one of the major sources of China’s soy.

When we last spoke this month, Hunke had recently turned in his dissertation, a body of research on the water and soil of the Cerrado, and how intensive agriculture is harming both. His work is pioneering, but there are still major gaps in our knowledge of the soy industry’s impact on this region, which is both one of earth’s most important ecosystems and, more recently, one of its most important agricultural lands.

Put onto ships and moved out the Port of Santos, the Cerrado’s soybeans are a global resource. But that means the environmental calamity caused by their production is also a global problem. Even if it is right to place soy production above the health of the Cerrado, growing soy there will only become more difficult as intensive farming erodes the Cerrado’s soil. If this is how the world must feed itself, the world may be in trouble. But what if there was another way?

What's next? See the next stories in this series:

Holding Ground
What does it take to raise beef on the edge of American agriculture?

The Ecology of Knowledge
How do farmers learn to be soil stewards? We asked some from all over the world.

Common Ground
What can Cuba teach the world about preserving its soil?

Did you miss part one?

From the Ground Up
Though we don’t think about it, soil is a finite resource — a living ecosystem that’s way more complex, important and fragile than you think.

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