Saving the planet: biking and soil-erosion

Take the bike, leave the car 

The weather has finally turned. At the beginning of April we had a snow storm, at the end of it we had 81 degrees F (27 degrees C). Our upstairs neighbor, who is about the most conservative person we know, proclaimed:

“I really don’t believe in global warming, but this weather could make one fall for it!”

Well…

One good thing: I don’t feel bad about pushing my husband to ride his bike to work (it’s a 2.5 mile ride, but Boston and Cambridge aren’t the most biker friendly places). I find it hard to insist that someone make a sacrifice that doesn’t affect myself (I work from home and have all I need within walking distance).

And he did so, today. I’m proud of him.

Composting and soil erosion

On the home front we are winning our bid to put a compost bin in the back of our condo building. I’m looking forward to cutting the amount of waste our household produces in half, and to giving back to the earth some of what we take from it.

Everyone takes soil for granted. We don’t think about it as nutritious: along with the sun, it is the lowest (the “rock bottom”) of our food chain. Science magazine called it the “Final Frontier”. The Natural Resources Conservation Service (NRCS), previously the Soil Conservation Service, part of the United States Department of Agriculture (USDA) describes it less passionately:

  • Soil is the material that is formed from rocks and decaying plants and animals; it makes up the outermost layer of the earth. There are at least 70,000 kinds of soil in the United States. Topsoil is considered the most productive soil layer. (Fact Sheet, April 1993.)

And we don’t realize that we are losing it at an alarming rate (though let’s not get “hysterical” about it!). The Agricultural Research Service, another department of the USDA, “Soil erosion can degrade the quality of agricultural soils, and introduce sediment, nutrients, pesticides and pathogens into surface waters” (ARS 2005 Report). The numbers:

  • Arable land, with its fragile top 6 inches of fertile soil, determines the productivity of our food system. More than 99% of U.S. food comes from this land while less than 1% comes from aquatic systems. Of the 2.3 billion acres of U.S. land, only 20% is sufficiently fertile for crop production. Nearly 400 million acres of arable land now are in cultivation in the U.S. to produce our food. (Die Off)
  • In terms of acres: In 2003, 102 million acres (28% of all cropland) were eroding above soil loss tolerance rates…  266 million acres (72% of cropland) were eroding at or below soil loss tolerance rates… Highly Erodible Land (HEL) cropland acreage was about 100 million acres. (NRCS 2003 Annual NRI)
  • In terms of tons, NRCS version: Between 1982 and 2003, soil erosion on U.S. cropland decreased 43%. Water (sheet & rill) erosion on cropland in 2003 was down to 971 million tons per year, and erosion due to wind was at 776 million tons per year. (NRCS 2003 Annual NRI)

“It decreased!” my neighbor would say, “we’re saved!”

Not so fast: 

  • Erosion of agricultural lands occurs about 17 times faster than soil formation, and about 90 percent of all U.S. cropland is losing soil faster than the sustainable rate. About 1.5 to 2.0 billion tons of soil is lost from fields annually through soil erosion. (ARS 2005 Report)

The cost of soil erosion is estimated to be about $37.6 billion annually (in the US).

In one of my favorite books, It’s a Long Road to a Tomato, Keith Stewart writes (p.113):

The poisoned and lifeless topsoil gets washed into our rivers and blows away in the wind… Money spent attempting to slow the rate of soil loss, while probably well spent, is another hidden cost at the supermarket checkout counter. But surely it is buried somewhere in our tax bills.”

And it will truly surface in the futures of our children.

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