Plan B 4.0: Mobilizing to Save Civilization


Lester R. Brown

Chapter 8. Restoring the Earth: Conserving and Rebuilding Soils

The literature on soil erosion contains countless references to the “loss of protective vegetation.” Over the last half-century, people have removed so much of that protective cover by clearcutting, overgrazing, and overplowing that the world is quickly losing soil accumulated over long stretches of geological time. Preserving the biological productivity of highly erodible cropland depends on planting it in grass or trees before it becomes wasteland.




In the United States, where farmers during the 1990s were required to implement a soil conservation plan on erodible cropland in order to be eligible for commodity price supports, the no-till area went from 7 million hectares in 1990 to 27 million hectares (67 million acres) in 2007. Now widely used in the production of corn and soybeans, no-till has spread rapidly in the western hemisphere, covering 26 million hectares in Brazil, 20 million hectares in Argentina, and 13 million in Canada. Australia, with 12 million hectares, rounds out the five leading no-till countries. 37


A number of these agricultural practices can have the added benefit of increasing the carbon stored as organic matter in soils. Farming practices that reduce soil erosion and raise cropland productivity usually also lead to higher carbon content in the soil. Among these are the shift to minimum-till and no-till farming, the more extensive use of cover crops, the return of all livestock and poultry manure to the land, expansion of irrigated area, a return to more mixed crop-livestock farming, and the forestation of marginal farmlands.

Other approaches are being used to halt soil erosion and desert encroachment on cropland. In July 2005, the Moroccan government, responding to severe drought, announced that it was allocating $778 million to canceling farmers’ debts and converting cereal-planted areas into less vulnerable olive and fruit orchards. 39

Sub-Saharan Africa faces a similar situation, with the desert moving southward all across the Sahel, from Mauritania and Senegal in the west to the Sudan in the east. Countries are concerned about the growing displacement of people as grasslands and croplands turn to desert. As a result, the African Union has launched the Green Wall Sahara Initiative. This plan, originally proposed by Olusegun Obasanjo when he was president of Nigeria, calls for planting 300 million trees on 3 million hectares in a long band stretching across Africa. Senegal, which is currently losing 50,000 hectares of productive land each year, would anchor the green wall on the western end. Senegal’s Environment Minister Modou Fada Diagne says, “Instead of waiting for the desert to come to us, we need to attack it.” Since the initiative was launched, its scope has broadened to include improved land management practices such as rotational grazing. 40

China is likewise planting a belt of trees to protect land from the expanding Gobi Desert. This green wall, a modern version of the Great Wall, is projected to extend some 4,480 kilometers (2,800 miles), stretching from outer Beijing through Inner Mongolia (Nei Monggol). In addition to its Great Green Wall, China is paying farmers in the threatened provinces to plant their cropland in trees. The goal is to plant trees on 10 million hectares of grainland, easily one tenth of China’s current grainland area. Unfortunately, recent pressures to expand food production appear to have slowed this tree planting initiative. 41


The Helin County strategy centers on replacing the large number of sheep and goats with dairy cattle. The dairy herds are kept within restricted areas, feeding on cornstalks, wheat straw, and the harvest from a drought-tolerant forage crop resembling alfalfa, which is used to reclaim land from the desert. Local officials estimate that this program will double incomes within the county during this decade. 43

To relieve pressure on China’s rangelands as a whole, Beijing is asking herders to reduce their flocks of sheep and goats by 40 percent. But in communities where wealth is measured in livestock numbers and where most families are living in poverty, such cuts are not easy or, indeed, likely, unless alternative livelihoods are offered to pastoralists along the lines proposed in Helin County. 44


Protecting the earth’s soil also warrants a worldwide ban on the clearcutting of forests in favor of selective harvesting, simply because with each successive clearcut there are heavy soil losses until the forest regenerates. And with each subsequent cutting, more soil is lost and productivity declines further. Restoring the earth’s tree and grass cover, as well as practicing conservation agriculture, protects soil from erosion, reduces flooding, and sequesters carbon.

Rattan Lal, a senior agronomist with the Carbon Management and Sequestration Center at Ohio State University, has calculated the range of potential carbon sequestration for many practices. For example, expanding the use of cover crops to protect soil during the off-season can store from 68 million to 338 million tons of carbon worldwide each year. Calculating the total carbon sequestration potential from this broad scope of practices, using the low end of the range for each, shows that 400 million tons of carbon could be sequestered each year. Aggregating the numbers from the more optimistic high end of the range for each practice yields a total of 1.2 billion tons of carbon per year. For our carbon budget we are assuming, perhaps conservatively, that 600 million tons of carbon can be sequestered as a result of adopting these carbon-sensitive farming and land management practices. 46

