LEARNING MODULE SAMPLE/TEMPLATE

Week 2: Soil Physical Properties

OverviewSoil physical properties are the most obvious soil properties; we can see and feel them. Soil physical properties have tremendous influence over what we can do with soil – grow things on it, build on it, build IN it, play on it, and everything else we want to do with land. Some physical properties are easy to influence through management decisions. Some physical properties are practically impossible to change. This week, we’ll find out why.

Learning ObjectivesAfter completing this week in the course, you will be able to:

1. Distinguish among the closely related concepts of soil texture, soil structure, soil consistence, specific surface area, ped, aggregate, clod, porosity and total pore space.

2. Define hue, value, and chroma and describe a soil color in those terms, using the Munsell color scheme. Name the three factors that generally influence soil color and identify the factors we can influence through management.

3. Describe the three main soil separates by size and explain why clay is so much more chemically reactive and physically influential than sand. Explain why soil texture is a “master variable.”

4. Use the textural triangle to determine a soil texture, use a hydrometer to quantify soil texture, and perform a “feel method” to describe soil texture in the field.

5. Define and calculate bulk density and discuss the significance of bulk density to soil functioning.6. Suggest a basic mitigation plan for agricultural soil that has become compacted due to tillage at

inappropriate moisture contents, and describe management strategies for maintaining good soil tilth in a loam soil used for agriculture. Explain why is it so important to protect the integrity of the soil surface for redwood or sequoia forests, desert ecosystems, and other fragile areas.

7. Evaluate the pros and cons of using a particular piece of land for agriculture based on its physical properties of both surface and subsurface horizons. Evaluate the pros and cons of using a particular piece of land for some other purpose, based on its physical properties of both surface and subsurface horizons.

Learning Activities Outside ClassProvided to students ahead of time:

(Optional, recommended) Watch this video that introduces the reading: https://connect.cpp.edu/ch4physicalproperties/

Read Chapter 4 in "Elements of the Nature & Properties of Soils." Make reading notes, using the reading guide (to be turned in).

Learning Activities Inside Class Not provided to students ahead of time:

Brainstorm physical properties (recall) Mini-lecture – interpret different data depictions and explain why the data looks as it does Interpret a horizon description Read and use the texture triangle Fill in table 4.1 from book (recall/reasoning) Begin problem set – identity properties being asked for and begin each problem. Complete for

homework.