B. Describe how soil is formed, and define terms of formation; Begins when Parent Material or Rock is weathered Weathering: process when the climate breaks.

Things to Know

• Aeration: The presence of oxygen.

• Pore Spaces: Air holes between soil particles.

• Inorganic: Non living substances.

• Organic: Anything that is or once was living.

Things to know

• Soil Amendment: Items added to the soil to increase plant growth.

• Pasteurization: Process of heating soil to 180 degrees F to kill harmful diseases, weed seeds, and insects.

• Macronutrients: Elements needed by the plant in large amounts.

Things to know

• Fertilizer: Any material provided to plants to supply the nutrients needed for plant growth.

• Fertilizer Analysis: Statement on a fertilizer bag indicating the amount of primary elements in a fertilizer.

Types of Media

• Soil

• Soilless medium: Contains no topsoil.

• Hydroponics: Growing plants in water solutions.

Things media should provide:

• Media should hold nutrients.

• Adequate drainage- plants can die from lack of oxygen.

• Some consistency.

Organic Matter

Mineral Matter

Air

Water

Explain the nature and composition of Soil;

• Soil is the outer layer of the earth

• Dirt is displaced Soil Air Water Organic Matter Mineral Matter

• Composition of average Soil a. 25% Air b. 25% Water c. 5% Organic Matter d. 45% Mineral Matter

• Pore Space: Spaces between solid matter, air and water will fill pore spaces

Components of Soil

• Sand: The largest soil particle

• Silt: Is smaller than sand but larger than clay.

• Clay: The smallest soil particle.

List and define mineral components of soil;

• Mineral Matter: inorganic material, non- living– Particles are labeled as Sand, Silt and

Clay

• Sand: largest particle– Large pore space, good aeration– Well drained– Not fertile, unable to hold nutrients– Feels gritty

• Silt: mid sized particle– Good water holding capacity– Retains nutrients– Feels like flour dry, velvet wet

• Clay: Smallest particle– Ability to hold

water and nutrients

– Small pores, poor aeration and drainage

– Hard clumps when dry, feels sticky when wet

Discuss soil texture and the textural triangle;

• Soil Texture: determined by proportions of the three types of mineral particles– Each Soil type has a name – Example: 40% sand, 20% clay, 40% silt, loam

soil

• Common Soil types– Sandy Soil: Looseness, well aerated, good

for root crops– Silty loam Soil: Very fertile, good to grow in.– Clay Soil: Heavy, dries very hard.

Textural Triangle: uses percentages of particles to determine soil types.

Soil Textural TriangleExample: 40% Sand20% Clay40% Silt

E. Define Organic Matter and common soil amendments:

• Organic Matter: the accumulation of decayed or partially decayed plants and animals.

• Common additions of Organic matter to soil:– Manure, animal waste– Green “Manure”, or cover crop that is plowed

into the ground.– Peat Moss or Compost, common for gardeners

F. Describe water relationships in the soil;

• Three main types of ground water.– Gravitational Water: Free flowing water

pulled down by gravity.• Flows quickly through sand, slowly through clay• Leaching: as water moves through soil it carries

with it nutrients, salts and chemicals.

– Capillary Water: held between particles, moves up and sideways through soil.

• As soil dries out, it pulls water up though the pore space

• Plant available

Hygroscopic Water: water held in a thin film around the individual soil particles

• Not plant available

Soil pH

• Soil pH can range from 1-14

• pH’s of 1-6 are acidic.

• pH’s of 7 are neutral.

• pH’s of 8-14 are alkaline.

Soil pH

• Most plants prefer a pH of 5.6 – 7

• To raise the pH add limestone.

• To lower the pH add sulfur.

G. Describe the role of air in the soil;

• Air should make up 25% of the soil sample

• Air is in the pore space, fills with water after rain

• Must have a balance between air and water to maintain most plant life. – Too much water (lack of air),

fermentation– Not enough water (too much air), wilted

plants

H. Explain soil structure;

• Aggregates: large clusters of soil particles

• Soil Structure: the way which aggregates are arranged (8 types of structures)– Granular: most desirable– Crumb: also desirable– Platy– Prismatic– Massive– Columnar– Blocky– Single grain

8 Types of Structure

I. Illustrate and label soil profiles;

• Soil is arranged in layers called:– Horizon: layers of soil in the profile

• Five major horizons, all horizons have names• Depth and thickness of horizon vary

depending on location

• Main Horizons– O horizon- Litter Layer, Organic material – A horizon- Top Soil, most fertile, up to

10 inches deep – C horizon- Sub soil, some nutrients

leached from above– R horizon- Bedrock, or solid rock, parent

material

• Damage: Humans can destroy soil structure– Driving heavy equipment on

when wet– Working Soil when excessively

wet•Clay particles clog pore spaces, soil

compaction.• Poor drainage, plants cannot grow

J. Discuss the process of soil erosion, its importance, and

prevention.• Erosion: the removal of soil by wind

or water– Loosing valuable soil that then can

pollute water and air– Soil Conservation

• Agricultural practices: Strip cropping, terraces, no till

• Wild land and home owners: plant roots can anchor soil in place