Soils

Graduation Requirements
Science Earth and Space Laboratory
Field & Cluster
Agriculture
Equipment/Materials Needed

100ml Graduated Cylinder
Shovel

soil
Description

Soil is a living and life-giving natural resource. As world population and food production demands increase so will the demands on our soil

Badge Completion Requirements

Introduction to Soil

Only "living" things can be healthy. So, when we discuss soil health we're talking about a living breathing organism.

Soil is the interface between land, air, organic material, and rock. If you pick up a hand full of soil you'll be holding about 45% rock-based material, 25% Water, 25% Air, and 5% Organic matter or humus.

45% rock-based material or minerals- will be composed of a mixture of sand, clay, silt, and gravel.

25 % Water- all soil has a water holding capacity depending on the soil's composition

25% Air- all life in the soil will depend on the ability of the soil to allow penetration of oxygen

05% Organic material- the mass of both living and non-living carbon sources

Soil is composed primarily of minerals which are produced from parent material (rock) that is weathered or broken into small pieces. Beyond occasional stones, gravel, and other rock debris, most of the mineral particles are called sand, silt, or clay. 

Sand, silt, and clay give soil it's texture. 

Sand particles range in diameter from 2 mm to 0.05 mm, are easily seen with the unaided eye, and feel gritty. [One millimeter (mm) is about the thickness of a dime.] 

Silt particles are between 0.05 mm and 0.002 mm and feel like flour. 

Clay particles are smaller than 0.002 mm and cannot be seen with the unaided eye. Clay particles are the most reactive mineral ingredient in the soil. Wet clay usually feels sticky.  

chart

Five characteristics that determine soil composition:

  • Parent material
  • Climate
  • Living organisms
  • Landscape position
  • Time

 Please review the following:

 

 

 

 

Experiment

Objective

To determine the composition of soil from 3 locations

Materials

100ml graduated cylinder

shovel

Safety

Normal laboratory safety will apply

Procedure

Select a location and collect a soil sample (dig a hole about 6 in deep, spade the soil a few times to break up the large pieces)

Collect 50 ml of soil

Add 50 ml of water

Shake for 3 minutes

Bring the volume back to 100ml 

Shake for 3 minutes

Allow the set overnight 

soil test

**(sand will be the bottom layer, silt will be the next, clay will be the top layer, and the organic material will be floating)

Result/Data

Record the ml's of sand, silt, clay, and organic material

Determine the % of each in your sample

     Math help

          Determine the milliliters of sand the bottom layer

          If you have 15ml of sand 

               15 divide by the total sample (50ml) times 100 for the percentage of  sand in the mixture

          Repeat for silt, clay, and organic material

Repeat for the two addition samples

Conclusion

Report the soil makeup of your tested locations

Prompts

Discuss the process of how rocks become soil 

Explain how climate affects soil types

Explain how topography affects soils 

Explain the term porosity and how it relates to soils

Discuss the horizons in the soil

Please develop and submit a presentation demonstrating your understanding of soil and its structure. Please include the above "prompts" in your presentation

 

 

Introduction to Soil (part 2)

Introduction to Soil (part 2) is a continuation of Introduction to Soils (part 1). In this section, we'll be introducing particle size, horizons, and soil sampling.

Design and build a soil sample probe and demonstrate its use 

Prompt

 

Explain the sampling procedure and equipment required

Discuss the reasons that someone would take soil samples for analysis 

Explain the soil texture triangle and how to use it

Discuss a soil profile 

Please develop and submit a presentation demonstrating your understanding of soil science. Please include the above "prompts" in your presentation