review physical properties of soils??. review physical properties of soils?? soil texture soil...

Review

Physical properties of soils??

Review

Physical properties of soils?? Soil texture Soil structure Density

Review

Chemical properties of soils??

Review

Chemical properties of soils?? pH CEC

Review

Chemical properties of soils?? pH CEC

What is the pH of agricultural soils?

Review

Chemical properties of soils?? pH CEC

What is the pH of agricultural soils? between 6 and 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?

Plant Nutition

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?

Introduction

60 or more elements are found in plants. 17 essential

Introduction

60 or more elements are found in plants. 17 essential

Macronutrients Micronutrients

Enzyme cofactors

Macronutrients

Introduction

60 or more elements are found in plants. 17 essential

Macronutrients Micronutrients

Enzyme cofactors

Micronutrients

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

Nitrogen Nitrogen role in plants

Protein Base pairs for RNA/DNA Chlorophyll Hormones (ABA, cytokinins)

Nitrogen Nitrogen role in plants

Protein Base pairs for RNA/DNA Chlorophyll Hormones (ABA, cytokinins)

Nitrogen Nitrogen role in plants

Protein Base pairs for RNA/DNA Chlorophyll Hormones (ABA, cytokinins)

2% of DW Which type of transport

requires ATP?

Nitrogen deficiency Poor, stunted growth

with pale leaves and weak stems.

Leaves often turn orange or red, may fall prematurely. Fruit trees Vegetables

Phosphorus

ATP/ADP DNA/RNA Phospholipids

Membrane Phosphoproteins 10% of N

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

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.

Iron

Enzyme activator Required for

chlorophyll synthesis

When soils are alkaline, iron may become unavailable.

Applications of an acid nutrient formula can help.

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

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.

Soil, Water and Minerals

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

• Size

• Concentration

Soil, Water and Minerals

Ca2+ vs. Na+

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

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

Acidic Soils

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

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

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

Nitrogen

Why is Nitrogen important for plants?

Nitrogen

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

hormones

Nitrogen

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

hormones Do you remember the symptoms

of nitrogen deficiency?

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

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.

Nitrogen Fixation by Bacteria

Review• Macro and Micronutrients

– Importance to plants– Deficiency symptoms

• Ion and soil particle interactions• Cation exchange• Nitrogen fixation