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