Teaching Organic Farming and Gardening

Soil Physical Properties

Unit 2.1 | 25
Instructor’s Demonstration 1 Outline

Demonstration 1: Soil Texture Determination

for the instructor

Instructor overvIew

The following demonstration

outline covers the resources and

skills used to determine the texture

of a given soil sample by feel and

to determine the approximate

percent of sand, silt, and clay in

that sample. First demonstrate how

to use the Soil Texture Decision

Chart to identify the texture of

a given sample. Following this,

give students the opportunity

to identify the approximate soil

textural classification of several

additional soil samples. The Soil

Texture Triangle is used to help

students determine the approximate

percent of sand, silt, and clay in

their samples. The Soil Texture

Descriptions are included to

help confirm the accuracy of

the determination by providing

descriptions of how the soil feels and

performs under several tests.

MaterIals

•    Multiple   samples of  different   kinds   of  soil    textures

•    Handouts   (see    below)

1. The Soil Texture Decision Chart: How soil texture is
   
   determined


2. The Soil Texture Triangle: The percentatges of sand, silt,
   
   and clay in each textural classification


3. The Soil Texture Descriptions: How the soil feels and
   performs under several tests

DeMonstratIon tIMe

About   1   hour

DeMonstratIon outlIne

A. Demonstrate how to determine the soil texture of a

given sample by feel using the Soil Texture Decision

Chart (next page)

B. Determine the percentage of sand, silt, and clay in the

soil sample using the Soil Texture Triangle (page 27)

C. Use the Soil Texture Descriptions (pages 28–29) to

confirm the accuracy of the textural determination

D. Students practice determining soil texture following

the same steps

E. Once a texture has been determined, describe/discuss

the characteristics of each of the soils

1. Drainage


2. Water-holding capacity/drainage


3. Nutrient-holding capacity


4. Describe/discuss how each of the example soils may be
   
   improved using organic farming practices