Our Loess Becomes Someone Else’s Grain?

Pesky facts indicate the Earth’s arable land and usable water supply are more endangered than polar bears. However, further dangers exist. Even assuming enough space and water to grow food for all of us, there’s yet another issue to consider: topsoil.

Vegetation protects land from wind and rain, but we need to eat so we plant, we harvest, we pasture or graze livestock. Unfortunately plowing and overgrazing exposes topsoil to wind and rain. Much exposed soil blows away or sloughs off into the river systems. (That’s why there’s this HUGE dead zone that grows larger every day in the Gulf of Mexico, but I’m not getting into that here.  If you care, Google this: hypoxia gulf mexico)

Here’s a map done by the Global Assessment of Human Induced Soil Degradation, a study conducted by the International Soil Reference and Information Centre at Wageningen, The Netherlands, as commissioned by the United Nations Environment Program. I got this map from the “Land Degradation” section of the University of Michigan’s site on human impacts on the Earth.

If you are American and like to eat, you should find this map alarming because that dark red strip down the middle of the USA indicates very degraded soil, areas of “serious concern.” How serious? Read this from that U Mich site:

Areas of serious concern include zones where up to 75% of the topsoil has been lost already. The central portion of the United States is an area of particular local concern. The practices of large scale mechanized monoculture has contributed to the decline in soil in the mid-west.

In case you aren’t from the United States, that dark red area is also known as THE CORN BELT and THE BREADBASKET OF AMERICA. This area was gifted with enormous deposits of silt, loess, the most productive farmland known.

American or not, people should be getting more than a tad worried. I’m betting some have probably noticed all that nice green to the north on that map. Green indicates “stable terrain,” so it’ll save us, right?

Sorry.

Even if global warming exists and those areas some day end up with a long, bright, warm, growing season that’s not likely to save us. Much of that land has thin, acid soil, and that’s not what one looks for in farmland.

Perhaps some are now thinking that it’s just a matter of finding where topsoil has blown or washed away to. Other people could just plant where it ended up and everything will balance out: Our loess will just become someone else’s grain.

Sorry. It ain’t that easy. Yes, topsoil indeed blows around and settles again. In fact, Chinese topsoil has been found in Hawaii. The fundamental problem with our topsoil is the same as our problem with aquifers: We are using it up faster than it can rebuild.

Estimates available from reliable sources–farm groups, colleges, and so forth–indicate it takes the Earth at least 100 years for form an inch of topsoil. Most sites say 200 or 500 or even a 1000 years.

Don’t believe me? Google it: inch topsoil rebuild

Every site I’ve hit says we are losing our soil at a much faster rate than it can rebuild because of MAN.

For example, that U Mich site says, “The world’s croplands are in decline due to the pressure of human activities.”

The European Joint Research Commission Land Management and Natural Hazards Unit on Soil Erosion says, “The main causes of soil erosion are still inappropriate agricultural practices, deforestation, overgrazing, forest fires and construction activities.”

The Seattle PI carried this article: “The Lowdown on Topsoil: It’s Disappearing”

Here’s another bit from Britain’s the Daily Telegraph: “Britain Facing Food Crisis As World’s Soil ‘Vanishes in 60 Years’”

Of course, there are answers. We can hope for some bio-engineered crop that loves saline water, grows well in broken cement, takes little to no fertilizer, tastes like ice cream, and prevents tooth decay, but I’m not counting on that. Safer answers lie in better agricultural practices, for example, no-till farming, mulching, use of cover crops, and reduction of grazing.

Unfortunately, these can be much more labor intensive and/or less suitable for our current, huge, corporate monoculture farms. In other words, methods better for the soil will likely reduce crop yields and increase the price of food.

Americans are quite spoiled by the low price of food, but I suspect that’s going to change over the next few years and decades, not only because of topsoil degradation but because of other factors now looming.

Expect another post on our agricultural system soon.

Cassandra

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