1. 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  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.

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.  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.

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  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  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. 5-10-15 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 100 x 100 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