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This post is part of a series in which we look at why those basic things that we take for granted--such as water, food, and fuel--are getting expensive and scarce, all at once.
Really, Peak Dirt- the world is losing soil 10 to 20 times faster than it is replenishing it. Drake Bennett in the Boston Globe tells us that dirt is complicated stuff, made from sand or silt, then years of plants adding nutrition, bugs and worms adding their excrement, dying and rotting.
"The resulting organic matter feeds a whole underground ecology that aerates the soil, fixes nutrients, and makes it more hospitable for plant life, and over time the process feeds back on itself. If the soil does not wash away or get parched by drought, it very gradually thickens. It takes tens of thousands of years to make 15 centimeters of topsoil, about 6 inches' worth."
Till it and plant a monoculture like corn on it and that soil gets depleted rapidly, so farmers add fertilizer, lots of it. The philosophy was "Well, if your soil's degraded, just put some more fertilizer on, or till it another time and you can get the same crop yield," says David Laird, a soil scientist.
Unfortunately, we are also at Peak Fertilizer- the price of it has doubled and supplies are short. What is going on?
Blame Ethanol. The distortions in world agriculture caused by using food as fuel just keep spreading. Corn production requires huge amounts of fertilizer (much of which washes into the Mississippi River and is creating a dead zone in the Gulf of Mexico).
Blame Peak Oil. Not only is demand for fertilizer up, but it is made from natural gas, which has increased in cost along with oil. Five percent of the world's natural gas is used in making it.
Blame Meat. In the United States almost half of the fertilizer is used for feed or pasture. As demand for meat grows with Asia's exploding middle class, more fertilizer is needed per calorie of food delivered, since meat is such an inefficient way of delivering calories.
So once again, the same forces are conspiring to convert surplus to shortage: excessive demand for grain, caused mainly by pressures from ethanol and meat production. Fortunately, scientists are figuring out other ways to enrich soil:
1. Biochar It is what you get when biomass is heated in the absence of oxygen through a process called pyrolysis. When incorporated into soil, biochar provides the structural habitat needed for a rich community of micro-organisms to take hold. Its production also sequesters carbon. Tim McGee writes in Treehugger: Biochar is a classic win-win scenario, a solution that can provide us with a valuable tool for fighting climate change, world hunger, poverty, and energy shortages all at the same time."
2. Traditional Farming Methods. For centuries, farmers rotated among crops that used nitrogen from the soil, like corn, with those that fix it in the soil, like legumes. No-till farming is also becoming popular.
3. Make Soil from Scratch. In Australia, soil scientist Dick Haynes is making synthetic soil from fly ash, biproducts of aluminum processing, poultry litter and manure.
Many people are talking Mathusian these days, and blaming our problems on population growth. However when one sees so much of our dirt being abused to make fuel and meat, one has to agree with George Monbiot that to do so is to blame the billions of poor for the excesses of the rich.
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