Soil-What should be in it! Objectives: As a result of this lesson, the student will:

1
Section Plant Soil Science Unit Unit 7
Soil Management Lesson Title Lesson 1
Introduction to Soil Fertility and pH with Soil
Sampling Lab
2
Most popular macronutrients in soil
Slide 2

• Nitrogen------N
• Phosphorus-----P
• (usually in the form of P2O5)
• Potassium-------K
• (usually in the form of K2O)

3
What does nitrogen do?
Slide 3

• Most popular macronutrient
• It give a plant its green color
• Assists with rapid growth and vigor
• Promotes seed and fruit development
• Increases protein and yield

4
Phosphorous (P2O5) is important why?
Slide 4

• Aids seedlings to germinate
• Very important in the early stages of the crop
• Stimulates root growth

5
What does Potassium (K20) do?
Slide 5

• Responsible for production of carbohydrates in
  the plant,
• Produces plumper seeds
• Acts as the water valve for letting water in and
  out of the plant.

6
What are fertilizers?
Slide 6

• Help plants get the nutrients they need by adding
  deficient materials to the soil.
• It makes nutrients more available to the plant to
  get what it needs

7
How can we find out what is in the soil?
Slide 7

• Visual Inspectionnot accurate
• Tissue Culturesaccurate but expensive
• Soil Testmost widely accepted form of testing

8
What forms are fertilizers found?
Slide 8

• Dry (granules)
• Liquid (usally diluted with water)
• Gas (anhydrous ammonia)
• Solids (manure)
• Spikes (concentrated quantities placed in ground
  and allowed to dissipate through soil)

9
Reading a bag of fertilizer
Slide 9
N -P- K

• 20-15-10
• 20 Nitrogen
• 15 Phosphorus
• 10 Potassium

10
How many pounds are in there?
Slide 10

• Assume the bag is 100 pounds
• 20 Nitrogen means there is 20 pounds of Nitrogen
• Phosphorus in the form of P2O5 15 X .446.6 lbs
  
• Potassium in the form of K2O 10 x .83 8.3 lbs
• For bags smaller than 100 lbs, multiply your
  pounds by the pounds in the sack then divide by
  100. Example of 50 lb sack.
• 8.3x50/100 4.15 lbs of Potassium
•  

11
Math problems
Slide 11
      A 50 bag of 10-10-10 N P K__        
A 50 bag of 10-20-15 N P K__         A
100 bag of 20-10-0 N P K__  
12
Answers to math problems
Slide 12
      A 50 bag of 10-10-10 N 5 P 2.2 K
4.15   A 50 bag of 10-20-15 N 5 P 4.4
K 6.225     A 100 bag of 20-10-0 N 20 P
4.4 K 0
13
What is pH?
Slide 13

• pH is the scale we use to measure acidity (sour)
  to basic (bitter).
• What is the range of pH?
• You are right the range is 0-14.

14
pH Scale
Slide 14
15
What does pH measure?
Slide 15

• pH is the measure of how an item reacts with
  water. If it gives off hydrogen ions (H) it is
  an acid.
• An example would be hydrochloric acid. When it
  meets water it forms hydrogen ions and chloride
  ions.
• A base give off hydroxide ions when reacting with
  water.
• Sodium hydroxide is a base because it forms
  sodium ions and hydroxide ions when mixed with
  water.

16
Why do we need to know pH?
Slide 16

• Knowing the pH of our soil is important for two
  reasons
• It allows us to figure what amendments we might
  need to make the soil more efficient for the crop
  we are to be growing
• It also determines nutrient availability (some
  nutrients become unavailable to plants at low or
  high pH levels)