By Julian Wong Feb.24.2009
In: agriculture
1 comment

Soils and Sustainability: Tales from the Loess Plateau

The Loess Plateau at Linxian, ShanxiAs unlikely as it sounds, if there is one thing that holds the key to China’s sustainable future, that one thing is soils.  Indeed, it would be no exaggeration to emphasize that soils lies at the heart of the food-water-energy trilemma, which this blog has been harping on as of late (see previous post).

Soil is really where all life begins. Most obviously, our food sources depend on it.  Soils are also a vital links global nutrient and water cycles.  Less well known is the immense potential of soils to act as vast carbon sinks, with the ability to “naturally turn over about 10 times more greenhouse gas on a global scale than the burning of fossil fuels.”

Understanding the significance of this last fact relies on the appreciation that displacing all fossil fuel power plants with solar and wind farms, while necessary in curbing the flow of additional greenhouse gases into our atmosphere, does nothing to capture the prevailing stock of greenhouse gases accumulated from 150 years of industrialization and that will remain in the atmosphere for upwards of a hundred or more years to come.  This distinction between stock and flow of greenhouse gases hearkens to the need to capture atmospheric carbon.  This need is especially acute when one tries to comes to terms with the likelihood of cutting our global greenhouse gas emissions by 60 to 80% by 2050, which is what most experts agree we need to do to stabilize our climate (i.e. highly unlikely at current practices).   While the fossil fuel industry tries it hands at by squandering billions of dollars of research on unfeasible technical solutions such as geological sequestration of carbon emissions from power plants, soils are a natural solution which has been proven for hundreds of millions of years of biological and evolutionary history.

Recently, we highlighted the statistic that China has up to 3.57 million square kilometers of degraded lands, i.e. lands experiencing “heavy water and soil loss.”  The scale of such soil degradation is unimaginable; such an area is equivalent to the area of ten Germanys!  One of the major casualties of soil degradation is the Loess Plateau (pictured), the 640,000 sq. km feature that covers almost significant parts of Shanxi, Shaanxi, and Gansu provinces, the Ningxia Hui Autonomous Region, and which takes its name after Loess soil, whose silty properties make it highly erosion prone.

I recently came across a great feature story entitled “Our Good Earth” by Charles Mann in last September’s edition of National Geographic on soils.  The bits on relating to China focused on the Loess Plateau are so fascinating and I feel compelled to reproduce the relevant excerpts verbatim.  There is no happy ending here, but in a future post, I will describe the efforts of a true ecopreneur and his incredible efforts to restore the lands of the Loess Plateau and other regions.

For now, soak in the Nat Geo excerpt…

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Journalists sometimes describe unsexy subjects as MEGO: My eyes glaze over. Alas, soil degradation is the essence of MEGO. Nonetheless, the stakes-and the opportunities-could hardly be higher, says Rattan Lal, a prominent soil scientist at Ohio State University. Researchers and ordinary farmers around the world are finding that even devastated soils can be restored. The payoff, Lal says, is the chance not only to fight hunger but also to attack problems like water scarcity and even global warming. Indeed, some researchers believe that global warming can be slowed significantly by using vast stores of carbon to reengineer the world’s bad soils. “Political stability, environmental quality, hunger, and poverty all have the same root,” Lal says. “In the long run, the solution to each is restoring the most basic of all resources, the soil.” [bold added: the food-water-energy nexus!]

When I met Zhang Liubao in his village in central China last fall, he was whacking the eroded terraces of his farm into shape with a shovel-something he’d been doing after every rain for more than 40 years. In the 1960s, Zhang had been sent to the village of Dazhai, 200 miles to the east, to learn the Dazhai Way-an agricultural system China’s leaders believed would transform the nation. In Dazhai, Zhang told me proudly, “China learned everything about how to work the land.” Which is true, but not, alas, in the way Zhang intended.

Dazhai is in a geological anomaly called the Loess Plateau. For eon upon eon winds have swept across the deserts to the west, blowing grit and sand into central China. The millennia of dust fall have covered the region with vast heaps of packed silt-loess, geologists call it-some of them hundreds of feet deep. China’s Loess Plateau is about the size of France, Belgium, and the Netherlands combined. For centuries the silt piles have been washing away into the Yellow River-a natural process that has exacerbated, thanks to the Dazhai Way, into arguably the worst soil erosion problem in the world.

After floods ravaged Dazhai in 1963, the village’s Communist Party secretary refused any aid from the state, instead promising to create a newer, more productive village. Harvests soared, and Beijing sent observers to learn how to replicate Dazhai’s methods. What they saw was spade-wielding peasants terracing the loess hills from top to bottom, devoting their rest breaks to reading Mao Zedong’s little red book of revolutionary proverbs. Delighted by their fervor, Mao bused thousands of village representatives to the settlement, Zhang among them. The atmosphere was cultlike; one group walked for two weeks just to view the calluses on a Dazhai laborer’s hands. Mainly Zhang learned there that China needed him to produce grain from every scrap of land. Slogans, ever present in Maoist China, explained how to do it: Move Hills, Fill Gullies, and Create Plains! Destroy Forests, Open Wastelands! In Agriculture, Learn From Dazhai!

Zhang Liubao returned from Dazhai to his home village of Zuitou full of inspiration. Zuitou was so impoverished, he told me, that people ate just one or two good meals a year. Following Zhang’s instructions, villagers fanned out, cutting the scrubby trees on the hillsides, slicing the slopes into earthen terraces, and planting millet on every newly created flat surface. Despite constant hunger, people worked all day and then lit lanterns and worked at night. Ultimately, Zhang said, they increased Zuitou’s farmland by “about a fifth”—a lot in a poor place.

Alas, the actual effect was to create a vicious circle, according to Vaclav Smil, a University of Manitoba geographer who has long studied China’s environment. Zuitou’s terrace walls, made of nothing but packed silt, continually fell apart; hence Zhang’s need to constantly shore up collapsing terraces. Even when the terraces didn’t erode, rains sluiced away the nutrients and organic matter in the soil. After the initial rise, harvests started dropping. To maintain yields, farmers cleared and terraced new land, which washed away in turn.

The consequences were dire. Declining harvests on worsening soil forced huge numbers of farmers to become migrants. Partly for this reason, Zuitou lost half of its population. “It must be one of the greatest wastes of human labor in history,” Smil says. “Tens of millions of people forced to work night and day on projects that a child could have seen were a terrible stupidity. Cutting down trees and planting grain on steep slopes—how could that be a good idea?”

In response, the People’s Republic initiated plans to halt deforestation. In 1981 Beijing ordered every able-bodied citizen older than 11 to “plant three to five trees per year” wherever possible. Beijing also initiated what may still be the world’s biggest ecological program, the Three Norths project: a 2,800-mile band of trees running like a vast screen across China’s north, northeast, and northwest, including the frontier of the Loess Plateau. Scheduled to be complete in 2050, this Green Wall of China will, in theory, slow down the winds that drive desertification and dust storms.

Despite their ambitious scope, these efforts did not directly address the soil degradation that was the legacy of Dazhai. Confronting that head-on was politically difficult: It had to be done without admitting Mao’s mistakes. (When I asked local officials and scientists if the “Great Helmsman” had erred, they changed the subject.) Only in the past decade did Beijing chart a new course: replacing the Dazhai Way with what might be called the Gaoxigou Way.

Gaoxigou (Gaoxi Gully) is west of Dazhai, on the other side of the Yellow River. Its 522 inhabitants live in yaodong-caves dug like martin nests into the sharp pitches around the village. Beginning in 1953, farmers marched out from Gaoxigou and with heroic effort terraced not mere hillsides but entire mountains, slicing them one after another into hundred-tier wedding cakes iced with fields of millet and sorghum and corn. In a pattern that would become all too familiar, yields went up until sun and rain baked and blasted the soil in the bare terraces. To catch eroding loess, the village built earthen dams across gullies, intending to create new fields as they filled up with silt. But with little vegetation to slow the water, “every rainy season the dams busted,” says Fu Mingxing, the regional head of education. Ultimately, he says, villagers realized that “they had to protect the ecosystem, which means the soil.”

Today many of the terraces Gaoxigou laboriously hacked out of the loess are reverting to nature. In what locals call the “three-three” system, farmers replanted one-third of their land-the steepest, most erosion-prone slopes-with grass and trees, natural barriers to erosion. They covered another third of the land with harvestable orchards. The final third, mainly plots on the gully floor that have been enriched by earlier erosion, was cropped intensively. By concentrating their limited supplies of fertilizer on that land, farmers were able to raise yields enough to make up for the land they sacrificed, says Jiang Liangbiao, village head of Gaoxigou.

In 1999 Beijing announced it would deploy a Gaoxigou Way across the Loess Plateau. The Sloping Land Conversion Program-known as “grain-for-green”-directs farmers to convert most of their steep fields back to grassland, orchard, or forest, compensating them with an annual delivery of grain and a small cash payment for up to eight years. By 2010 grain-for-green could cover more than 82,000 square miles, much of it on the Loess Plateau.

But the grand schemes proclaimed in faraway Beijing are hard to translate to places like Zuitou. Provincial, county, and village officials are rewarded if they plant the number of trees envisioned in the plan, regardless of whether they have chosen tree species suited to local conditions (or listened to scientists who say that trees are not appropriate for grasslands to begin with). Farmers who reap no benefit from their work have little incentive to take care of the trees they are forced to plant. I saw the entirely predictable result on the back roads two hours north of Gaoxigou: fields of dead trees, planted in small pits shaped like fish scales, lined the roads for miles. “Every year we plant trees,” the farmers say, “but no trees survive.”

Some farmers in the Loess Plateau complained that the almonds they had been told to plant were now swamping the market. Others grumbled that Beijing’s fine plan was being hijacked by local officials who didn’t pay farmers their subsidies. Still others didn’t know why they were being asked to stop growing millet, or even what the term “erosion” meant. Despite all the injunctions from Beijing, many if not most farmers were continuing to plant on steep slopes. After talking to Zhang Liubao in Zuitou, I watched one of his neighbors pulling turnips from a field so steep that he could barely stand on it. Every time he yanked out a plant, a little wave of soil rolled downhill past his feet.

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