By Linda Meuth

Today, we will learn Importance of soils How soils are formed Components of soils

Figure 1. The soil cycle is a continuous process.

Importance of Soils

The production of food is dependent upon the ability of our soils to sustain plant life.

Soil is the original source of most nutrients for all plant and animal life. (Figure 1)

Soils are formed through a combination of five important

factors.Parent materialClimateLiving organismsTopographyTime

Parent Material is the horizon of unconsolidated material from which a soil develops. Horizon means layer.

Natural fertility and texture are influenced by the parent material.

ClimateParent material is broken down into finer particles by a process called weathering, which is controlled by the climate of a given location.

Climatic factors, such as temperature and rainfall, greatly affect the rate of weathering.

Living OrganismsMicrobes, plants, insects, animals, and humans influence soil formation by causing decay or breakdown of plant and animal residues in the soil.

Cultivation, bulldozing, and construction projects disturb soil surface layer and greatly modify soil-forming activities.

Topography Topography is the amount of slope of the land.

On a steep slope, loose material is moved downward by runoff water, gravity, and movement of humans and animals

Slope affects percolation. Percolation is the movement of water through the soil.

TimeSoils are formed by the chemical and physical weathering of parent material over time, as affected by climate, living organisms, and topography.

Takes hundreds of years for these factors to form one inch of soil from parent material.

How to take a soils sample

Check out soil sample

http://www.mo15.nrcs.usda.gov/features/wissoil/sld006.htm

Soils develop into layers called horizons.An ideal soil profile will have four horizons.Profile means a cross-sectional view of soil.

Horizon O – Horizon A – Horizon B - Horizon C – *Horizon R –

Soil is composed ofMineral matterOrganic matterWater Air

Soil Air Experiment

Place clod sprayed with polyurethane into jar of water.

Watch the bubbles. Air will bubble from some clods for up to 20 minutes or more.

Record your results on your card.

Mineral Matter InorganicProvides nutrientsFormed from weathered parent material or rock material

Organic matterDecomposed plant or animal matter originating from plant roots, above-ground crop residue, green manure crops, and livestock manure

organic matter yields soil microorganisms

Provides carbon, hydrogen, and oxygen to the soil

Helps soil hold water and nutrients

Soil Biology Primer [online]. Available: http://soils.usda.gov/sqi/concepts/soil_biology/soil_food_web.html [January 28, 2008].

video

Earthworms

Water bears

Fungi

Water and Air Necessary for plant growth:

photosynthesis, carry nutrients, respiration Amount varies dependent on climatic

conditions and water drainage

Water and air are in the tiny spaces known as pores between soil particles.

Today, we learned Importance of soils How soils are formed Components of soils

“The Diggin’ Men”Oh do you know the diggin’ men?Oh do you know the diggin’ men?Oh do you know the diggin’ men, they dig at Teitelman.

The soil is hard.The class is long, The pay is small,Not half way done.

Oh yes I know the diggin’ men, they dig at Teitelman.

This soil song, sung to the tune of “Oh Do You Know The Muffin Man.”

By Dana, Nicole, and Corie, 8th graders, R.M. Teitelman School, Cape May, NJ

Have we hit bedrock yet?

Next class….Soil Properties & Mud Pies!