January 10, 1995
Item: “US will export 30% more corn,” trumpeted the US Feed Grain Council on “US Farm Report” last year. Obviously a “Good Thing”–more exports, more income, more jobs, the usual litany–right? Perhaps not.
We’ve heard for many years about the impact of carbon-containing gases in the atmosphere–chlorofluorocarbons (CFCs) that disrupt the ozone layer, hydrocarbons that contribute to global warming. But there’s another carbon cycle that is equally critical to environmental health, and ultimately human survival–carbon in soils, the other part of the carbon cycle, and the other carbon crisis.
Modern agriculture has all-too-often treated soil as an inert, lifeless medium whose job was simply to provide a physical structure to support crops, while nutrients were delivered in handy chemical form by a cooperative, distant and energy intensive industrial system. A kind of hydroponics in the field.
In fact topsoil teems with invisible life which plays an invaluable role in the productivity of fields and forests; the varied forms of soil carbon in turn play a critical role in the life of the topsoil. Soil organic matter serves as a rich holding framework for nutrients and water. It contributes to soil tilth, which in turn reduces traction requirements, and thus energy needed. It provides energy for soil organisms, which play critical role in making nutrients available to plants and even in soil formation–a battle we’ve been losing.
It all sounds pretty technical. But here’s what it means: Once again, we have replaced a natural process that works with industrial life support. What’s worse, we’ve eroded it. Which in turn drives an accelerating negative cycle, affecting both productivity and productive capacity.
Industrial support means jobs, doesn’t it? True, in that the food industry has grown as farm populations have shrunk. But the whole system is based on trading soil for oil.
Analysts have estimated that each bushel of corn “costs” two bushels of topsoil, lost to erosion by wind and rain. But let’s translate the science into the language of the marketplace. The US loses some three billion tons of topsoil each year. To buy that much topsoil–say in 50 pounds bags from your local megahardware stores–you’d spend $478.8 billion. By comparison, Americans spent $309 billion in food stores in 1987 (the last year for which figures are available). Of course you wouldn’t buy that much topsoil retail; but even at the wholesale prices of a landscape supply company, you’d still have to write a check for about $108 billion–which is a lot when you consider that total US agricultural exports in 1991 were just shy of $56 billion.
Let’s push the analogy with one more data point: energy imports. You could say that we throw away $108 billion of soil to sell $56 billion of food to pay for $66 billion of oil. Something’s wrong with that balance sheet, especially since we build soil at perhaps one-tenth the rate at which we deplete it.
This is the unacknowledged achilles heel of the biofuels strategy. Long touted as an ecological panacea to the energy crisis, biofuels technologies extract fuels from plants or plant wastes–in principal, a renewable energy strategy. But if we grow our energy under the same cultivation regimes that have characterized modern commercial agriculture and forestry, it may not be a sustainably renewable resource.
Biofuels depend on the harvest of “wastes,” arguably the excessive harvest of wastes. The problem is that crop residues aren’t waste, but a critical link in this other carbon cycle. We are just beginning to think about “zero waste” industries, where one process’s waste becomes another process’s feedstocks. How ironic to disrupt that exchange in the agricultural and forest systems that industry is beginning to learn from.
Fortunately many US farmers have been getting the message, shifting from plowing to no-till, while a small but growing minority have been getting off the chemical bandwagon altogether with organic farming. Even agriculture department officials–in the US, England, Sweden, and other countries–have begun to advocate a “sustainable agriculture” that depends on maintaining the regenerative capacity of soils to biologically renew their productivity, year after year.
This holds serious implications for Developing Countries, which don’t have the topsoil reserves that fueled the US economic miracle perhaps as much as any other factor. There’s been a headlong rush in the world to “develop” agriculture along the US model–massive inputs of machinery, fuels, chemicals, in a drive to increase labor productivity. But as the US gradually moves to ‘low-input” agriculture–both because the chemical strategy is expensive, and because its fails the sustainability test–it would be ironic if developing countries adopted an agriculture strategy that was modern in the 1950s, but is hopelessly old fashioned today.