Soil Introduction

Soil Introduction​

• 45% minerals and nutrients*

• 25% air filled pore spaces

• 25% water filled pores spaces

• 5% organic matter

​

Ideal Soil Composition

*Will be the focus of our lab.

Multiple Choice

What percent of the soil is minerals and nutrients?

• 5%

• 25%

• 45%

• 50%

Multiple Choice

What percent of the soil is pore spaces?

• 5%

• 25%

• 45%

• 50%

Multiple Choice

What part of the soil will we be looking at in lab?

• Minerals and nutrients

• Air filled pore spaces

• Water filled pore spaces

• Organic matter

​2.0 - 0.05 mm

​​Sand

​

0.05 - 0.002​ mm

Silt

​

Less than 0.002mm

​​Clay

​

​Soil Types

​Soil characteristics are based on particle size.

Reorder

Arrange the following soil types from the smallest particles to the largest.

• Clay

• Silt

• Sand

1

2

3

• 1
• 2
• 3

Particle Size Effects

• Water and nutrient hold capacity: how much water and nutrients (nitrates & phosphates) and the soil can hold onto

  • Increases as particle size decreases

• Workability: the measure of how easily the soil can be used for specific reasons (AKA - How easily it can be plowed / farmed)

  • Increases as particle size increases

• Aeration: the gas exchange rate

  • Increases as particle size increases

Multiple Choice

What type of soil would have the greatest nutrient holding capacity?

• Sand

• Silt

• Clay

Multiple Choice

What type of soil would have the greatest aeration?

• Sand

• Silt

• Clay

Multiple Choice

What type of soil would have the least workability?

• Sand

• Silt

• Clay

Most soil is not

100% Clay, Silt, or Sand.

Most soil is a mixture. In fact,

the best soil for farming is loam,

a mixture of all three.​

​Textural Triangle

​LOAM

40% Sand

40% Silt

20% Clay​

Multiple Choice

When finding the percentage of clay, you would read the textural triangle...

• straight across from left to right starting on the left side of the triangle.

• up towards the left starting from the bottom of the triangle.

• down towards the right starting from the left side of the triangle.

Multiple Choice

When finding the percentage of sand, you would read the textural triangle...

• up towards the right starting at the bottom of the triangle.

• down towards the left starting from the right side of the triangle.

• up towards the left starting from the bottom of the triangle.