Fractals Speak the Language of the Universe from the Ground Up

Fractal geometry, a math of the rugged shapes of nature, has come to the forefront in the past decade. It is being used to analyze everything from stock prices and soil quality to cow temperatures.

Fractal geometry gets its name from the irregular fractals it deals with, repetitive fragments that a computer can combine to draw natural shapes from clouds to soil pores, the spaces between soil particles through which air and water move.

Walter J. Rawls, who heads the Hydrology Laboratory operated by USDA's Agricultural Research Service in Beltsville, Md., is using fractal geometry to predict soil water movement based on the geometry of soil pores. Those same measurements are also being used to judge soil quality. The measurements are made from thinly sliced sheets of soil encased in resin.

Other ARS scientists are using fractal measurements to detect heat stress in cows. Cows, like people, have random fluctuations in body temperatures that resemble stock market fluctuations. Fractal line dimensions range from 1 for a straight line to almost 2 for the chaotic squiggle of body temperatures or stock prices.

Fractals can reveal when cows are losing their ability to regulate their body temperatures-- when air temperature is around 80 degrees F. This gives feedlot managers a vital clue to when to turn on the water sprinklers.

An article on fractal geometry project appears in the April issue of ARS' Agricultural Research magazine. The article is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/apr98/frac0498.htm

Scientific contact: Walter J. Rawls, Hydrology Laboratory, Beltsville, Maryland, phone (301)504- 7490, fax (301) 504-8931, wrawls@hydrolab.arsusda.gov.