1. Fertilizers and Plants
Plant Environment
Fertilizers and Plants

2. Objectives Determine the roles of plant nutrients for plant growth.
Describe the effects of external factors (water, light, and temperature) on plant adaptation and development
Identify optimum soil and water pH for ornamental and forage crops.
Identify the hardiness charts to determine temperature zones for areas within the state.

3. 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

4. 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

5. 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.
, the mixture is 10% N, 10% P, and 10% K. The total is 30% elements.
The other 70% is a filler like lime.

6. 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

7. Nitrogen Cont. Too Much Too Little
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

8. Phosphorus Uses 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

9. Phosphorus Cont. Too much Too little Cause container plants to dry out
Cause a white deposit on soil surface
Too little
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

10. Potassium Uses Resistance to disease Strong root system
Essential for starch formation
Chlorophyll
Efficient use of carbon dioxide

11. Potassium Cont. Too Little
Cause plants to appear dry and scorched on the edges with irregular yellow areas on the surface

12. 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

13. Micronutrients Iron (Fe) Manganese (Mn) Copper (Cu) Zinc (Zn)
Boron (B)
Molybdenum (Mo)
Chlorine (Cl)
Cobalt (Co)

14. 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.

15. Inorganic fertilizers
Refers to nonliving materials like chemical salts.
These fertilizers are usually easily handled, applied quickly and in concentrated amounts.

16. Calculating Fertilizer Requirements
Complete Fertilizer Container has
N-P-K amounts on label Ex
5% N
10% P
15% K =
30% of fertilizer is nutrients
5% + 10% + 15% = 30%
30% of fertilizer are the nutrients
Other 70% = filler
Filler usually consists of lime

17. Calculating Fertilizer by Area
N, P, or K content (number on bag) = actual N, P, K x

18. External factors that affect plants
Temperature
Light
Moisture

19. 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

20. 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

21. Moisture Water needed for photosynthesis Humidity affects plant growth
Water is a solvent for nutrients and other materials needed by the plant

22. Limiting Factor Concept
Optimum Growth Conditions are desired for crops
Limiting factor is something that prevents plant from growing to its optimum yield

23. 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

24. 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

25. Plant Hardiness Zone Map
Louisiana Plant Hardiness Zones
8A/ 8B =10-15/15-20 F
9A/ 9B = 20-25/25-30 F