By Rod Nickel, Ayenat Mersie and David Stanway
WINNIPEG/NAIROBI/SHANGHAI- In America’s dusty Corn Belt this spring, the land was drowning. In China’s Yangtze river basin, it’s bone dry. Farmers in both are fighting a losing battle to save the soil that produces our food.
Carolyn Olson figures she did everything she could to protect her 1,100-acre farm near Cottonwood, Minnesota. She grows three-foot-high tall-grass buffer strips around her fields to protect the soil and in winter plants crops to provide ground cover.
But torrid rainstorms in May washed away so much soil during planting season that she expects the crop to suffer.
“When you get that much rain, almost four inches in about an hour, even your best practices fly out the window,” said the 55-year-old, whose farm has been in her husband’s family since 1913.
By contrast, there’s not enough water in the vast Yangtze basin, which produces a third of China’s crops. Scientists are resorting to firing rockets into clouds to “seed” them with rain artificially in the hope of replenishing soil drained of nutrients by sizzling temperatures.
It’s no silver bullet, though.
From the United States and China to Kenya, human efforts to preserve soil are proving no match for increasingly extreme weather, which is damaging the living system and depleting its ability to produce food, according to Reuters interviews with dozens of farmers, scientists and other soil specialists.
Soil erosion could lead to a 10 percent loss in global crop production by 2050, according to the UN’s Food and Agriculture Organization (FAO). With the world’s population forecast to rise by a fifth to nearly 10 billion by then, malnutrition and famine is set to affect more and more people.
Few places are in deeper crisis than the pasturelands of northern Kenya, where ever-deepening drought has denuded the land of vegetation, exposing the soil to damage and confounding efforts to adapt farming methods.
“The soil left there is very vulnerable, like the skin of the Earth … you’re not wearing clothing when the sun’s beating down,” said Leigh Ann Winowiecki, a Nairobi soil scientist at CIFOR-ICRAF, a research center on the benefits of trees for people and landscapes.
Icing on cake
UN scientists say it can take up to 1,000 years for nature to produce 2-3 cm of soil, making preservation critical.
Plants grow by absorbing sunlight and carbon dioxide. They cycle the carbon into the soil, feeding microorganisms that in turn create the conditions for more plants to grow.
Extreme weather, some of it caused by climate change, not only damages crops but also erodes the soil and depletes nutrients such as carbon, nitrogen and phosphorus from the complex ecosystem, according to specialists.
This leads to land degradation – the decline of its ability to sustain plant life, and by extension animal and human life.
One-third of the world’s total land area is already degraded by erosion, nutrient depletion or in other ways, according to the United Nations.
Ronald Vargas, a soil scientist and secretary of the FAO’s Global Soil Partnership, said extreme weather was accelerating soil degradation already set in train by deforestation, over-grazing by livestock and improper use of fertilizer.
“Land degradation is a vicious cycle. Once you have degraded soils, and you have these bad (weather) events, then you have very bad second consequences,” Vargas said.
On the FAO’s projected loss in global crop production, he added: “This 10 percent represents a real issue to food security.”
Engineering the rain
The American Midwest, parched for rain this summer, is actually getting wetter over time.
Rainstorms over three days in mid-May washed away up to three tons of dirt per acre in two dozen Minnesota counties, according to data from the Daily Erosion Project, an Iowa State University initiative to estimate soil loss.
Rachel Schattman, assistant professor of sustainable agriculture at the University of Maine, said the US Midwest and Northeast were especially vulnerable to land erosion because they were receiving more extreme amounts of rain than normal, a trend expected to continue through the end of the century.
In the Yangtze river basin, wetter weather would be welcome. Farming belts in the region, stretching from Sichuan in the southwest to Shanghai on the east coast, received 40 percent less rainfall than normal over the summer and baked in record-high temperatures.
Liu Zhiyu, an official at the Chinese water ministry, said in August that a third of the soil in six key farming provinces along the upper and middle reaches of the Yangtze” was drier than is optimal as a result of the drought. In around a tenth of the rural counties in those provinces, soil was suffering from “severe water depletion”.
China’s cloud-seeding program offered some relief, with 211 operations launched in August alone to induce rainfall over 1.45 million square km of parched farmland, but experts say it’s no long-term solution.
“Artificial rainfall can only be the icing on the cake,” Zhao Zhiqiang, vice-director of China’s weather modification office, said at a media briefing in September. He did not say whether the operations were successful.
Similarly, other measures such as digging thousands of new wells and encouraging farmers to switch crops to boost yields have limited impact.
