Warm-Up 10/29

1. Do you or anyone in your family keep a garden?

2. When was the last time you worked or played in the soil?

3. Name a product that requires soil to be created.

4. What is in soil?

Warm-Up 11/1

1. What is soil?2. Is there only one kind of soil? If there is more

than one what is the difference between them?

3. Will plants grow equally well in all soil? What do plants need from soil?

Be sure to write the date on your warm-upRemember to turn in your warm-ups tomorrow.

SOIL

What is Soil?

• Soil – relatively thin surface layer of the Earth’s crust consisting of mineral and organic matter

SOIL: A RENEWABLE RESOURCE

• Soil is a slowly renewed resource that provides most of the nutrients needed for plant growth and also helps purify water.– Soil formation begins when bedrock is broken down

by physical, chemical and biological processes called weathering.

• Mature soils, or soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons.

Horizons• Layers of soil are called horizons.• O: consists of organic material

(decomposed or undecomposed)• A: still organic material-all

decomposed. TOPSOIL• B: lots of clay and lots of minerals.

SUBSOIL• C: BEDROCK. Where weathering is

still taking place to make new soil

Warm-Up 11/2

1. Give some examples of material that composes the organic layer

2. What does the mineral component of the soil contribute to plant growth?

3. What is the name for the different layers of visibly different soil that develop over time?

15 min of Reading

Soil Profile

• Soil is created from PARENT ROCK (the rock that gets weathered to create the soil)

• As that parent rock gets weathered and soil is formed, the soil will reside on top of the parent rock. This soil is called residual soil.

• Over time the residual soil forms layers

Parent Material• To form 2.5 cm (1 in.) it may take from

200-1000 years.

Soil Formation

What is soil?• A mixture of decomposing

organic matter and minerals.• Mineral component consists

of clay, silt, and sand.• Difference between clay, silt,

and sand—particle size.• Amounts of clay, silt, and

sand in soil can vary.

Soil Structure

The amount of sand, silt, and clay affects these important soil properties:– Ability of the soil to store water and nutrients– Speed that water will flow through the soil– How easily air can get in the soil– What kind of plants the soil will grow well– How deep plant roots can extend

13 mineral nutrients

• The three most vital nutrients are nitrogen, phosphorous and potassium.

• Provided by parent rock and organic matter!

Six macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S)

Seven micronutrients: boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn).

13 mineral nutrients

• Come from the soil, are dissolved in water and absorbed through a plant's roots.

• Not always enough of these nutrients in the soil for a plant to grow healthy.

• Farmers and gardeners use fertilizers to add the nutrients to the soil.

END

Examples of Agriculturally Significant Plants

• Barley• Rice • Wheat• Oats• Maize• Quinoa• Carrots• Beats• Potatoes• Onions• Garlic• Yam

• Yucca• Tarro• Black-eyed pea• Green bean• Chickpea• Lentils• Apples (various)• Oranges (various)• Banana• Coffee• Or anything else you can think of

or find!

Soil Conservation

• Farmers can prevent accelerated soil erosion by a few techniques…

• Contour plowing• Strip-cropping• Terracing• Crop rotation

Contour plowing: soil plowed in circular bands along the contours of the land.

Strip-cropping: crops planted in alternate bands

Terracing: creating step-like ridges in the slope

Crop rotation: one type of crop one year and another type the next year

END

What is soil?• A mixture of minerals, water,

gases, and the remains of dead organisms that is created by weathered rock.

• Consists of clay, silt, and sand.• Difference between clay, silt,

and sand—particle size.• Amounts of clay, silt, and sand

in soil can vary.

How does this help plants?

• Substrates for support• Water retention• Minerals and nutrients for growth• The three most vital nutrients are nitrogen,

phosphorous and potassium.

Composition – 4 Distinct Parts

• Mineral particles (45% of “typical” soil)• Organic matter (about 5%)• Water (about 25%)• Air (about 25%)

Importance

• Organisms, mainly microorganisms, inhabit the soil & depend on it for shelter, food & water.

• Plants anchor themselves into the soil, and get their nutrients and water. Terrestrial plants could not survive without soil, therefore, humans could not exist without soil either.