Tech Tip from the NRCS Science and Technology Deputy Area

Here are some fascinating "factoids" from the National Soil Survey Center that show why soil is such an important resource. Be sure to share them!

Your contact is Stan Anderson on (402) 437-5357.

• Shrinking and swelling of some kinds of soil damage buildings, roads, and other structures. Repairing this damage costs our Nation more each year than repairing the total damage from hurricanes, tornadoes, and floods.

• The tips of small plant roots move through the soil with a twisting screwlike motion. Mature trees can have as many as 5 million active root tips.

• A single spade full of rich garden soil contains more species of organisms than can be found above ground in the entire Amazon rain forest.

• Although the soil surface appears solid, air moves freely in and out of it. The air in the upper 8 inches of a well-drained soil is completely renewed about every hour.

• The plants growing in a 2-acre wheat field can have more than 30,000 miles of roots, greater than the circumference of the Earth.

• The wonderful "earthy" smell of newly plowed ground is believed to result from chemicals produced by micro-organisms. One of these chemicals, called geosmin, is produced by actinomycetes, organisms that have some properties of both bacteria and fungi.

• About 10 percent of the world's land is used to grow plants and to feed either animals or humans. About 20 percent of the land in the United States is used to grow crops.

• Soil can act as either a sink or a source of greenhouse gases. An estimated 30 percent of the carbon dioxide, 70 percent of the methane, and 90 percent of the nitrous oxide released to the atmosphere each year pass through the soil.

• Worldwide, an estimated 25 percent of the soils used for agriculture are being degraded at an unacceptable rate.

• The American Midwest has the largest area of Prime Farmland soils in the world. Other large areas are in South America and in Eastern Europe and Russia.

• In the spring of 1934, a dust storm originating in the Great Plains carried an estimated 200 million tons of soil to the Northeastern United States and out to sea. This storm caused "muddy rains" in New York and "black snows" in Vermont.

• In 1950, there was more than half an acre of grain land for each person on earth. By 1990, there was less than one-third acre per person. By 2030, there will be only one-fifth acre per person.

• At field capacity, the amount of water available for plant growth ranges from less than 5 to as much as 50 percent, with an average of about 15 percent.

• It takes about 4,000 to 6,000 pounds of crop residue per year to maintain the content of organic matter in a soil.

• Modern farming practices that minimize soil disturbance (plowing) and return plant residues to the soil, such as no-till farming and crop rotations, are slowly rebuilding the Nation's stock of soil organic matter.

• Of the carbon returned to the soil as plant residue, about 5 to 15 percent become tied up in the bodies of organisms and 60 to 75 percent is respired as carbon dioxide back to the atmosphere. Only 10 to 25 percent is converted to humus in the soil.

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  10/18/99