Review

1
Review

• Physical properties of soils??

2
Review

• Physical properties of soils??
• Soil texture
• Soil structure
• Density

3
Review

• Chemical properties of soils??

4
Review

• Chemical properties of soils??
• pH
• CEC

5
Review

• Chemical properties of soils??
• pH
• CEC
• What is the pH of agricultural soils?

6
Review

• Chemical properties of soils??
• pH
• CEC
• What is the pH of agricultural soils?
• between 6 and 7

7
Review

• Chemical properties of soils??
• pH
• CEC
• What is the pH of agricultural soils?
• between 6 and 7
• Why is this range the optimum condition?

8
Plant Nutition
9
Introduction

• How many elements do we find in plants?
• Do plants need all the elements in the same
  amount?
• How does agriculture effect the soil nutrients?
• What is the solution?

10
Introduction

• 60 or more elements are found in plants.
• 17 essential

11
Introduction

• 60 or more elements are found in plants.
• 17 essential
• Macronutrients
• Micronutrients
• Enzyme cofactors

12
Macronutrients
13
Introduction

• 60 or more elements are found in plants.
• 17 essential
• Macronutrients
• Micronutrients
• Enzyme cofactors

14
Micronutrients
15

• 60 or more elements are found in plants.
• 17 essential
• Macronutrients
• Micronutrients
• Enzyme cofactors
• What is the relationship between plant nutrition
  deficiency and humans or animals?
• China example

16
Nitrogen

• Nitrogen role in plants
• Protein
• Base pairs for RNA/DNA
• Chlorophyll
• Hormones (ABA, cytokinins)

17
Nitrogen

• Nitrogen role in plants
• Protein
• Base pairs for RNA/DNA
• Chlorophyll
• Hormones (ABA, cytokinins)

18
Nitrogen

• Nitrogen role in plants
• Protein
• Base pairs for RNA/DNA
• Chlorophyll
• Hormones (ABA, cytokinins)
• 2 of DW
• Which type of transport requires ATP?

19
Nitrogen deficiency

• Poor, stunted growth with pale leaves and weak
  stems.
• Leaves often turn orange or red, may fall
  prematurely.
• Fruit trees
• Vegetables

20
Phosphorus

• ATP/ADP
• DNA/RNA
• Phospholipids
• Membrane
• Phosphoproteins
• 10 of N

21
Phosphorus Deficiency

• Poor growth
• Fruits are small and acid tasting
• Leaves become brown or red if P is severely
  deficient.
• Corn and grassy plants
• Oldest leaves are affected first

22
Potassium

• Cofactor in osmosis
• Stomata control
• Protein synthesis
• Deficiencies
• Dull and spare flowers
• Low fruit yield and poor quality.
• Tissues become soft and susceptible to attack
  from pests.
• Brown scorching and curling of leaf tips, and
  yellowing of leaf veins. Purple spots may also
  appear on the leaf undersides.

23
Iron

• Enzyme activator
• Required for chlorophyll synthesis
• When soils are alkaline, iron may become
  unavailable.
• Applications of an acid nutrient formula can
  help.

24
Zinc

• Energy production
• Protein synthesis
• Formation of chlorophyll
• Growth regulation
• Deficiency Symptoms
• Delayed maturity
• Symptoms occur mainly in new growth
• Short internodes
• Decrease in leaf size

25
Soil, Water and Minerals

• Silicates (SiO4-4)?93 of earths crust
• Rings of water form around soil particles.
• Soil solution
• Cations and Anions dissolve in water.
• 50 of soil vol.

26
Soil, Water and Minerals

• What are some factors in ion binding to soil
  particles?
• Charge ( - )
• Size
• Concentration

27
Soil, Water and Minerals

• Ca2 vs. Na
• High conc. of Na vs. Low conc. of Ca2

28
Soil, Water and Minerals

• Why is it important to know these rules?
• Salty soils high levels of Na
• Useful ions end up in ground water
• Southwestern US

29
Acidic Soils

• Acidic soils are nutrient poor.
• Where do we find acidic soils?
• Why?

30
Acidic Soils

• Acidic soils are nutrient poor.
• Where do we find acidic soils?
• Why?
• CO2 H2O ? H2CO3 ? H HCO3-
• H displaces other cations.
• Acidic soils bring toxic ions into the soil
  solution
• Aluminum ions

31
Cation Exchange

• CO2 released from roots (indirect H)
• H can also be secreted (direct)
• H then replaces the mineral cations in soil
• Minerals are released
• Roots uptake the minerals

32
Nitrogen

• Why is Nitrogen important for plants?

33
Nitrogen

• Why is Nitrogen important for plants?
• Proteins, DNA, RNA, chlorophyll, and hormones

34
Nitrogen

• Why is Nitrogen important for plants?
• Proteins, DNA, RNA, chlorophyll, and hormones
• Do you remember the symptoms of nitrogen
  deficiency?

35
Nitrogen

• Why is Nitrogen important for plants?
• Proteins, DNA, RNA, chlorophyll, and hormones
• Do you remember the symptoms of nitrogen
  deficiency?
• Poor growth
• Weak stems
• Discoloration of leaves

36
Nitrogen and Bacteria

• N2 can not be used directly by plants
• NO3- or NH4
• Nitrogen fixation
• Soil bacterial - Rhizobium
• The conversion of N2 into NO3- or NH4
• Legumes are rotated with other crops to enrich
  the soil.

37
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38
Nitrogen Fixation by Bacteria
39
Review

• Macro and Micronutrients
• Importance to plants
• Deficiency symptoms
• Ion and soil particle interactions
• Cation exchange
• Nitrogen fixation