Introduction to Agriculture

Unit 2

INTRODUCTION TO SOILS

NAME ONE NATURAL RESOURCE

ANSWER• Occur naturally within the environment that exist

relatively undisturbed by mankind, in a natural form. Natural resources are derived from the environment. Many of them are essential for our survival while others are sued for satisfying our wants.

• Examples: coal, petroleum, land, air, water, mineral oil, copper, iron, and……… SOIL!

SOIL• The collection of natural bodies on the

earth’s surface, in places modified or even made by humans of earthy materials, containing living matter and supporting or capable of supporting plants out of doors.

WHAT IS THE DIFFERENCE BETWEEN SOIL AND DIRT?

• Is there a difference?

• Soil is loose mineral and organic material on earth’s surface that serves as a medium for the growth of land plants.

• NOT the same as dirt!!!

• DIRT IS SIMPLY MISPLACED SOIL!

WHAT SOIL DOES FOR OUR ENVIRONMENT

• Serves as a medium for plant growth

• Becomes an anchor for plant roots and keeps them upright

• Supplies plant with essential nutrients to support growth and life

• There are seventeen nutrients that can be considered “needed” for plant growth, plants can get fourteen of these from the soil

• Many of these nutrients are unavailable or insoluble for plants to use

• Leaves are able to absorb some nutrients but most come from the roots and root hairs

• Provides moisture (water) to the plant

• Since the roots are the plants absorbing body, moisture is stored in the soil

• Water holding is extremely important to agricultural use especially in Arizona

• Serves as a medium for seed germination

• Provides the correct environment for seed germination

• Moisture and temperature

• Engineering medium

• Difference soils are not designed for engineering

• Some soils are designed for water retention while other are used for buildings and construction

SOIL COMPOSITION• Soil is composed of 4 major

parts that influence the nature of the soil

1. Mineral matter

2. Air

3. Water

4. Organic matter

SOIL COMPOSITION• A handful of soil may seem solid, but only

half consists of solid material. The other half is pore spaces filled with air or water.

• It is important to have pore space because this is where roots can grow, water circulates and microscopic creatures live.

TAKE OUT A PIECE OF PAPER!1. Why is soil not dirt?

2. What are the four components of soil?

3. What is soil composed of? Half is ________________ and half is ________________.