Table of Contents Title: 7.3 Soil Texture, Fertility and Color Page #: 62 Date: 1/29/2013

Objectives Students will be able to differentiate among the factors of soil formation.

Words of the Day Hue: Color Value: Lightness or darkness Chroma: Intensity

Soil Texture Particles of soil are classified by their size. There are 3 classifications: 1) Clay (smallest particles) 2) Silt (medium particles) 3) Sand (largest particles) Particle size effects soil’s capacity to retain moisture and to support plant growth.

USDA Soil Classification

Soil Fertility Fertility: A measure of how well a soil can support growth. Factors of fertility: Topography Availability of minerals and nutrients Microorganisms present Amount and availability of precipitation Commercial fertilizers put nitrates, potassium and phosphorous into soils.

Soil Color Determined by the minerals, organic matter and moisture in each soil horizon. O and A horizons are dark in color = Rich in Humus Red and yellow soils = oxidation of iron minerals (rust) Yellow soils = environmental problems, poor drainage Gray / blue soils = poor drainage, little oxygen Scientists describe soil color using the Munsell System of Color Notation. 3 Parts: Hue (color) Value (lightness, darkness) Chroma (intensity)

The Munsell System of Color Notation

Using the Munsell System of Color Notation