Soil PropertiesFoundation Science 4 Class Code SC22102
What is Soil made of?Soil is made of:1) mineral particles2) organic matter3) water4) air
The Organic Matter in Soil is Mostly HumusWhen insects, worms, bacteria, and fungi and otherorganisms die they decay and form a material called“humus”.As more organisms die, the soil becomes more fertile.
Why is Soil Important? Much of the life on earth depends on soilSoil is just as important as water, air, and sunlight. – Without soil, there would be no plants. – Without plants, there would be no food, shelter or oxygen to breathe for humans or animals. Soil provides the nutrients needed by most plants to grow.
How are Soils Formed?1. Decomposition – animals and plants die and “feed” the soil
How are Soils Formed?1. Decomposition2. Weathering (not moving)– rain and wind break rocks down into soil
How are Soils Formed?1. Decomposition2. Weathering3. Erosion (moving)– when the rocks break and fall apart in the wind or rain
Soil Profiles• Soil forms in layers.• The set of layers is called a profile.
Soil Profiles• Sometimes the layers are called horizons.
Types of SoilThree Types: 1) Sandy soil contains large particles. Sandy soils stay loose and allow moisture to penetrate easily, but do not retain it for long term use. 2) Loam soil is a mix of sand, silt or clay, and organic matter. Loam soils are loose and look rich. 3) Clay soils are made of very small particles. They feel slick and sticky when wet.
Clay Soil is Slippery and Holds Water Up Remember, the particles in clay soil are very small
Sandy Soil does NOT Hold Water Sandy soil has large particles and holds air but not water
Loam Soil holds both Air AND Water Loam soil has both large and small particles an holds water and air well
All Three Soils… Loam Soil Clay SoilSandy Soil
What do Plants Need to Grow? 1. Air 2. Water 3. Nutrients Soil responsible for these 3 4. SunlightSo, if soil does not have a lot of air, plants won’t grow well.This is why clay soils are bad for plant growth.If soil does not have a lot of water, plants won’t grow well.This is why sandy soils are bad for plant growth.Loam soils can hold water and air, and are the best forplant growth.
Questions1. What is soil made of?2. What is humus?3. What are 2 reasons why soil is important?4. How are soils formed?5. What is a soil profile ?6. What are the 3 types of soil?7. Which soil is best for plant growth?8. What are the 4 things a plant needs to grow?9. A plant needs 4 things to grow, how many does it get from soil?10. Why are clay soils bad for plants to grow?11. What is sandy soil good at holding?12. What soil type is probably under this water?