SOIL SCIENCE

1. Explain why soil is so important.1. Explain why soil is so important.

• Only a fixed number of land in the USA.• Production of fruit, vegetables, grain, feed for

animals.

2. List the four main components of soil 2. List the four main components of soil and the percentage of each in the and the percentage of each in the

soil.soil.

• Organic matter 5%• Air 25%• Water 25%• Mineral matter 45%

COMPONENTS OF

3. Define soil texture.3. Define soil texture.

• Size of the soil particles

4. What are the main soil particles. List 4. What are the main soil particles. List them from largest to smallest.them from largest to smallest.

• Sand• Silt• Clay

Soil TextureSize of the soil particles

5. Why is it important for soil to contain 5. Why is it important for soil to contain a balance of sand, silt, and clay a balance of sand, silt, and clay

particles?particles?

• Gives the soil proper air movement (aeration)• Gives the soil proper moisture movement• Provides good support for the plant• Holds nutrients

6. List the five 6. List the five soil texture groupssoil texture groups and the and the soil textural classessoil textural classes found in each found in each

group. (Table 6-1)group. (Table 6-1)

• Fine Textured – Clay, Silty Clay, Sandy Clay• Moderately Fine Textured – Silty clay loam,

Clay loam, Sandy Clay Loam• Medium Textured – Loam, Silt loam, Silt• Coarse Textured – Sandy Loam, Loamy sand• Very Coarse Textured - Sand

7. What is the purpose of the 7. What is the purpose of the ribbon ribbon testtest??

• To determine the soil texture

8. What is the purpose of the 8. What is the purpose of the textural textural triangletriangle on page 75? on page 75?

• Used to determine soil texture

Example 1:

20% Clay 40% Silt40% Sand

What is the textural classification? _____________ LOAM

Using the Jar Method to Determine Textural ClassificationUsing the Jar Method to Determine Textural Classification

1. Fill jar about 1/3 with soil.

2. Fill with water.

3. Put lid on/Shake for 5 minutes.

4. Let stand for 24 hours.

5. Measure depth of sand, silt, clay.(use millimeters)

6. Calculate the percentage of each.

7. Use texture triangle to determinesoil texture classification. 30mm

10mm10mm

Total = 50mm30/50 = 60% Clay10/50 = 20% Silt10/50 = 20% Sand

30/50 = 60% Clay10/50 = 20% Silt10/50 = 20% Sand

Texture = ___________Clay

9. Define 9. Define soil structuresoil structure and list the six and list the six types of soil structures.types of soil structures.

• The way soil particles are grouped together to form clusters (aggregates)

• Single grain• Blocky• Platy• Massive• Granular• Prismatic

Soil structure is the shape that the soil takes based on its physical and chemical properties. Each individual unit of soil structure is called a ped. Take a sample of undisturbed soil in your hand (either from the pit or from the shovel or auger). Look closely at the soil in your hand and examine its structure. Possible choices of soil structure are:

Blocky: Irregular blocks that are usually 1.5 - 5.0 cm in diameter.

Blocky

Platy: Thin, flat plates of soil that lie horizontally. Usually found in compacted soil.

Platy

Massive: Soil has no visible structure, is hard to break apart and appears in very large clods.

Massive

Granular: Resembles cookie crumbs and is usually less than 0.5 cm in diameter. Commonly found in surface horizons where roots have been growing.

Granular

Prismatic: Vertical columns of soil that might be a number of cm long. Usually found in lower horizons.

Prismatic

10. Define soil pH.

• The level of acidity or alkalinity in the soil• ph = potential hydrogen• The amount of H in the soil

11. Why is 11. Why is soil pHsoil pH important for important for plant growth?plant growth?

• Soil pH determines how much of a nutrient is available for plant growth

12. Draw the 12. Draw the pH scalepH scale found on page 77. found on page 77.

13. List the 13. List the 16 elements16 elements that are that are necessary for plant growth.necessary for plant growth.

• C – Carbon• H – Hydrogen• O – Oxygen• P – Phosphorus• K – Potassium• N – Nitrogen• S – Sulfur• Ca – Calcium• Fe – Iron• Mg – Magnesium• B – Boron• Mn – Manganese• Cu – Copper• Zn - Zinc• Mo – Molybedenum• Cl - Chlorine

C HOPKNS CaFe Mg B Mn CuZn Mo Cl

14. Memory device

15 . List the three primary nutrients. Why are they important?

• Nitrogen

• Phosphorus

• Potassium

• Needed in the largest amount by plants

16. List the three secondary nutrients. How much of these do plants need?

• Calcium

• Magnesium

• Sulfur

• Needed in moderate amounts by plants

17. List the micronutrients. How much of these do plants need?

• Boron• Chlorine• Copper• Manganese• Molybedenum• Iron• Zinc• Needed in very tiny amounts

C HOPKNS CaFe Mg B Mn CuZn Mo Cl

From atmosphere

PrimarySecondary

Micronutrients

18. What can we determine about the soil 18. What can we determine about the soil by conducting a by conducting a soil testsoil test??

• The amount of nutrients in the soil

19. What is the purpose of a 19. What is the purpose of a plant plant analysisanalysis??

• Determine the nutrients in a plant

20. 20. Define the word Define the word fertilizingfertilizing..• Adding nutrients to the soil

Manure – natural fertilizer Compost – natural fertilizer

21. What are the 3 numbers on a fertilizer 21. What are the 3 numbers on a fertilizer bag and what do they mean?bag and what do they mean?

% of N, P, K

22. Define 22. Define complete fertilizercomplete fertilizer

Contains N, P, K

23. Define 23. Define slow release fertilizerslow release fertilizer

Slowly dissolves in the soil. May last several months.

24. What is the 24. What is the fertilizer ratio?fertilizer ratio?

The relative amount of N, P, K

Examples:

10-10-10 = 1:1:1

10-5-10 = 2:1:2

25. What is a 25. What is a soil profile? soil profile? (define and sketch example) (define and sketch example)

Diagram which shows the different layers of soil.

(Example on next slide)

SOIL PROFILE

26. What is 26. What is soil porosity? soil porosity? (define and sketch examples)(define and sketch examples)

The amount of space between the soil particles.

Greater porosity allows more air and water movement in the soil, a good thing.

(Examples on next 2 slides)

Porosity

Single Grained: Soil is broken into individual particles that do not stick together. Always accompanies a loose consistence. Commonly found in sandy soils.

Single-Grained

SOIL FORMATION

SOURCES OF ORGANIC MATTER

MANURE

COMPOST

PLANT NUTRIENTS

PLANT NUTRIENTS

Primary NutrientsN – NitrogenP – PhosphorousK - Potassium

Secondary NutrientsS – SulfurCa – CalciumMg - Magnesium

Micronutrients or Trace ElementsB – BoronCu – CopperZn – ZincMo – MolybdenumMn – ManganeseFe – IronCl - Chlorine

P deficiencyP deficiency

P deficiency is characterized by dark green plantsand purplish leaves.   

P deficient plants are typically "spindly."  Becauseof the marked effect that P deficiency has on retardingoverall growth.

Potassium deficiency is chlorosis of the lower, olderleaves that begins at the leaf tip and proceeds downthe leaf margins.

As the severity of K deficiency increases thesymptoms proceed up the affected plants.

K DeficiencyK Deficiency

POTASSIUM (K)

K comes from the latin word Kalium.

Potassium gets its name from the word potash.

SOIL AMENDMENTS

Peat Moss

Vermiculite

Perlite

Sand

Compost

Manure

Comes from a peat bog

Peat Moss

Sphagnum is a genus of between 1510 and 3500 species of mosses, commonly called peat moss due to its prevalence in wet habitats where it contributes to the formation of peat bogs and mires.

Sphagnum flexuosum

Decayed, dried sphagnum moss has the name of peat or peat moss. This is used as a soil conditioner which increases the soil's capacity to hold water and nutrients by increasing capillary forces and cation exchange capacity. This is often necessary when dealing with very sandy soil, or plants that need increased or steady moisture content to flourish. A distinction is sometimes made between sphagnum moss, the live moss growing on top of a peat bog, and 'sphagnum peat moss' (North American usage) or 'sphagnum peat' (British usage), the latter being the slowly decaying matter underneath.[18]

VermiculiteVermiculite is a hydrous, silicate mineral that is classified as a phyllosilicate and that expands greatly when heated.

Soilless growing media: exfoliated vermiculite is combined with other materials such as peat or composted pine bark compost to produce soilless growing media for the professional horticulturalist and for the home gardener. These mixes promote faster root growth and gives quick anchorage to young roots. The mixture helps retain air, plant food and moisture, releasing them as the plant requires them.

PerlitePerlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently.

In horticulture, perlite can be used as a soil amendment or alone as a medium for hydroponics or for starting cuttings. When used as an amendment it has high permeability / low water retention and helps prevent soil compaction.