2021 Iowa FFA Soil Judging CDE Exam

Upland

Landscape positions vary in soil composition and makeup. What landscape position would be normally be the oldest and most strongly developed or changed from the original parent material:

Redox Features

Presence of ________ at 12 inches or immediately below the dark surface layer will be used to determine evidence of a water table in topsoil.

Slope gradient

Terracing is the practice of constructing ridges and channels across the slope to intercept runoff water. The type and kind of terrace that is constructed on land depends on which of the following:

Absorption field

A(n) __________ is an area in which effluent from the septic tank is distributed into the soil through tiles or perforated pipes that are installed below the ground surface.

Organic matter content of the soils

Color of the A horizon is most related to the:

Generally have more than 40 inches of total soil profile depth, have textures that are in the medium category and have a dark or black A horizon color

Soils generally suited for a source of topsoil:

Moderately thick

A topsoil thickness for 10 inches of A horizon before a B horizon would be classified as:

All of these

Slope is an important characteristic in regards to the inherent potential of land. Slopes can be gentle to steep, short or long, and smooth or variable. All of these characteristics influence:

Slow

Which class of surface drainage fits the following condition? Water has an avenue of escape but, because of nearly level, but rough surface vegetation, water stands on the surface for several hours following a rain.

Loess

While judging soil, you discover a soil with silty materials without stratification. The parent material of this soil would be:

Alfisol

A soil without a thick, dark A horizon, but with significant clay accumulation in the B horizon in Iowa, would likely be a(n)

B Slope

A slope of 3% is considered to belong to which slope group in Iowa?

All of these

Which of the following influence soil color:

Contouring

Tillage and row crops planted across slopes is called:

Internal drainage is not needed

If a soil is well aerated and has low water holding capacity:

Moderately fine

Equal percentages of sand, silt, and clay would result in what textural group?

Gently sloping

A three percent slope is described as:

Class I

Land with a deep, somewhat poorly drained, medium textured soil with a 0-2 percent slope would be classified as:

Platy

______________ soil structure units are commonly found in E horizons and are significantly wider than they are tall

Somewhat poor natural drainage

Grayish-brown or olive gray colors of the B Horizon indicate:

Can significantly limit root growth

Compaction:

Moved primarily by gravity

Colluvium is a parent material that is:

False

Terraces must follow the exact contour.

Grass waterway

The best intermittent drainageway would be what?

Slightly eroded

Land in this erosion class has the nearest use potential and field management needs as it did originally when the settlers first started cultivating it.

Less than three feet

In evaluating building sites for houses with basements, bedrock is a limitation when soft bedrock is found:

2.0 mm

Rocks are defined as fragments greater than ___ in size.

Shapes formed by planes of weakness that develop as a soil changes

Structure is defined as the:

Texture

The proportions of sand, silt, and clay in soil determines its:

Raise the soil pH above neutral

Calcareous conditions _______________ and limit the availability of phosphorus and iron:

Color and acid test

Calcareous soils can be identified in what two ways:

Entisol

In Iowa, which soil order is most likely to be on flood plains?

Stay together for over 5 minutes

In a healthy soil, a soil aggregate will generally:

Moderately deep

A soil with a profile depth of 37 inches of soil before bedrock would be classified as:

All of these

Texture of the B horizon influences which of the following properties:

Higher proportion of clay

When compared to the A horizon, typically the B horizon’s texture has a:

Forest

Which native vegetation shows a thin A horizon due to how organic material has been added.

12.5%

Calculate the slope of a hill when in 80 feet of run the elevation drops 10 feet

Strip cropping

An effective practice to reduce wind erosion on level and gentle slopes to catch the soil that erodes from a cropped area is referred to as:

Geologic erosion

A very slow rate of erosion under natural conditions is called: