Amber Anderson; Lee Burras; and Gerald Miller


Slopes may be gentle or steep, short or long, and uniform or variable. All of these characteristics influence soil development, runoff, erosion, and land use, but only the steepness will be judged as a surface feature.
However, all of the slope characteristics may be considered in the interpretations section of the scorecard. Steepness of slope is measured on a percentage scale and is classified into slope groups.

The percentage scale tells how many feet the elevation rises (or falls) per 100 feet of slope length. Percent slope is always measured in the steepest direction at the site. Percent slope can be measured directly with a hand level or a clinometer designed for that purpose, or it can be calculated from elevation data. When the elevation method is used, the distance between the two stakes must be paced or measured. The elevation difference is then divided by the linear distance and multiplied by 100 to get percent slope.

The slope group is determined by comparing the percent slope with the scale given below. A slope that is exactly on the borderline between two groups is considered to belong in the steeper of the two groups. A SLOPE : 0-2% nearly level
B SLOPE : 2-5% gently sloping
C SLOPE : 5-9% moderately sloping
D SLOPE : 9-14% strongly sloping
E+ SLOPE :+14% steep


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Soil Judging in Iowa Copyright © 2023 by Amber Anderson; Lee Burras; and Gerald Miller is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.