Transcript Plant Environment - Louisiana Association of FFA

Plant Environment
Fertilizers and Plants
Objectives
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Determine the roles of plant nutrients for
plant growth.
Describe the effects of external factors
(water, light, and temperature) on plant
adaptation and development
Explain the limiting factor concept.
Identify optimum soil and water pH for
ornamental and forage crops.
Identify the hardiness charts to determine
temperature zones for areas within the state.
Primary Elements
 Available nutrients
 must be in soluble form before plants can
use them
 Absorbed by the roots
 May come from organic or inorganic
fertilizers
Plant nutrients
 Macro-nutrients – those needed in large
amounts
 Primary Macronutrients – N, P, & K
 Secondary Macronutrients – Ca, Mg, and S
 Micro – nutrients – those needed in very
small amounts
The major nutrients are
 N, P, K
 They are the main
ingredients in commercial
fertilizers.
 They are displayed by
three numbers on the
front of the bag.
 10-10-10, the mixture is
10% N, 10% P, and 10%
K. The total is 30%
elements.
 The other 70% is a filler
like lime.
Nitrogen
 Has the most noticeable effect on plants
 Uses
 Encourages aboveground growth
 Gives dark green color to the leaves
 Produces soft, tender, leafy growth for crops
such as lettuce and spinach
Nitrogen Cont.
 Too Much
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Lowers the plant’s resistance to disease
Weakens the stem
Lower the quality of fruit
Delay plant maturity and flowering
 Too Little
 Yellow or light green in color
 Stunted in root and top growth
Phosphorus
 Uses
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Encourages plant cell division
Essential for flower and seed production
Hastens maturity
Encourages root growth
Makes potassium more available
Increases resistance to disease
Improves the quality of grain, root, and fruit
crops
Phosphorus Cont.
 Too much
 Cause container plants to dry out
 Cause a white deposit on soil surface
 Too little
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Purple coloring on the undersurface of the leaves
Reduced flower, fruit, and seed production
Increased susceptibility to cold injury
Increased susceptibility to plant disease
Poor quality fruit and seeds
Potassium
 Uses
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Resistance to disease
Strong root system
Essential for starch formation
Chlorophyll
Efficient use of carbon dioxide
Potassium Cont.
 Too Little
 Cause plants to appear dry and scorched on
the edges with irregular yellow areas on the
surface
Secondary macronutrients
 Calcium
 Needed for cell walls to form
 Too little – cell tissue breaks down
 Deficiency symptoms – reduced root growth
 Magnesium
 Essential part of the chlorophyll molecule
 Deficiency symptoms – pale green color
 Sulfur
 Essential for chlorophyll formation
Micronutrients
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Iron (Fe)
Manganese (Mn)
Copper (Cu)
Zinc (Zn)
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Boron (B)
Molybdenum (Mo)
Chlorine (Cl)
Cobalt (Co)
Organic fertilizers
 Refers to material that is living or has come
from living organisms.
 Have low concentrations of N,P, and K.
 Makes soil loose and workable.
 Enhances the moisture holding capacity.
 Enhances the ability of the soil to retain and
make elements available.
 Reduces soil erosion.
Inorganic fertilizers
 Refers to nonliving materials like
chemical salts.
 These fertilizers are usually easily
handled, applied quickly and in
concentrated amounts.
Calculating Fertilizer
Requirements
Complete Fertilizer
Container has
N-P-K amounts on label
Ex. 5-10-15
5% + 10% + 15% = 30%
5% N
10% P
15% K =
Other 70% = filler
30% of fertilizer is nutrients
30% of fertilizer are the
nutrients
Filler usually consists of
lime
Calculating Fertilizer by Area
N, P, or K content (number on bag) = actual N, P, K
100
x
External factors that affect
plants
 Temperature
 Light
 Moisture
Temperature
 Warm season crops = soils temp >70
 Cool Season crops = soil temp < 70
 Different crops need different temps to
grow
 Plants have no temperature control
mechanism
Light
 Quantity-amount of light received
 Quality-amount of light of a certain color
that a plant absorbs or reflects
 Light duration- length of day
Moisture
 Water needed for photosynthesis
 Humidity affects plant growth
 Water is a solvent for nutrients and other
materials needed by the plant
Limiting Factor Concept
 Optimum Growth Conditions are desired
for crops
 Limiting factor is something that prevents
plant from growing to its optimum yield
Optimum soil and Water pH
 The effects of soil pH are determined by the
solubility of minerals and nutrients.
 Fourteen of the seventeen essential nutrients
come from the soil solution.
 Most minerals and nutrients are available in
acid soils than in neutral or alkaline soils
 Some nutrients become unavailable to plants
at low or high pH levels
Plant Hardiness Zone
 Maps that depict the hardiness zones for
plants throughout the United States
 Shows the average lowest winter
temperatures for a certain area
Plant Hardiness Zone Map
Louisiana Plant
Hardiness Zones
8A/ 8B =10-15/15-20 F
9A/ 9B = 20-25/25-30 F