Fertilize to Save Money

1. Fertilizing to Save Money Jason Kruse, Ph.D. University of Florida jkk@ufl.edu

2. Situation • Prices for many products have risen steadily • Revenue increases have not kept pace • Reduced budgets have resulted in staffing cuts • Increasing demands placed on existing facilities • Events • People • Increasing expectations regarding aesthetics and play

3. Situation • Expectations • Reduce/eliminate pesticides • Reduce/eliminate fertilizers • Organic??? • Goals • First and foremost – Safe, playable surface! • Make sure the turfgrass is not a point of discussion

4. Overview • Role of nutrients in plant growth • Fertilizer carriers - Nitrogen • Cultural management practices • Fertilizer price trends, predictions, purchasing recommendations

5. Role of Nutrients in Plants

6. Plant Nutrition • An actively growing turfgrass plant is 75 - 85% water. • The remaining 15 - 25% of the plant’s weight is dry matter. • Sixteen (16) elements are essential because a plant cannot successfully complete its life cycle without them. • A major portion of the plant dry matter content consists of three (3) elements: • Carbon • Hydrogen • Oxygen

7. Plant Nutrition • Plants obtain carbon and oxygen from the atmosphere. • Carbon dioxide (CO2), a gas, enters the leaves through the stomata. • Water (H2O) taken in by the roots supplies hydrogen and oxygen.

8. Essential Elements • Macronutrients • Nitrogen (N) • Phosphorus (P) • Potassium (K) • Secondary • Calcium (Ca) • Magnesium (Mg) • Sulfur (S) • Micronutrients • Iron (Fe) • Manganese (Mn) • Boron (B) • Copper (Cu) • Zinc (Zn) • Molybdenum (Mo) • Chlorine (Cl)

9. Macronutrients – Nitrogen (N) • Present in the greatest quantities: 2 – 5% in dry leaf tissue. • Sufficiency Ranges: • Creeping Bentgrass = 4.5 – 6.0% • Kentucky Bluegrass= 2.6 – 3.5% • Ryegrass = 4.5 – 5.5% • St. Augustinegrass = 2.0 – 3.0% • Zoysiagrass = 2.0 – 3.0% • Bermudagrass = 2.5 – 3.5%

10. Macronutrients – Nitrogen (N) • Major impact on a number of factors: • Effects on plant growth and metabolism, influencing grass response to a number of environmental stress conditions; • Potential environmental implications; • Must be routinely applied for a healthy, stress-tolerant turf; • Accounts for the highest cost of a turfgrass fertilization program.

12. Macronutrients – Nitrogen (N) • N Compounds in Plants - taken up as NO3- (nitrate) and NH4+(ammonium). • Amino acids – building blocks for proteins. • Proteins • Chlorophyll – photosynthesis • Hormones - auxins, cytokinins, and ethylene. • Nucleic Acids - DNA, RNA

13. Nitrogen Deficiency • The most common nutritional deficiency • Growth slows dramatically • Oldest leaves first become chlorotic (lose their dark green color, become yellowish), while newest leaves stay green. • Nitrogen is transferred from the oldest, expendable leaves to the newest, most valuable leaves

16. Macronutrients – Phosphorus (P) • Present in the soil solution in very low concentrations and uptake is primarily as H2PO4- (pH<7.0), HPO42- (pH>7.0), or certain soluble organic phosphates. • Phosphorus content of turfgrass shoot tissues may range from 0.10 to 1.00% by dry weight. • Sufficiency range is 0.15 – 0.5%.

17. Macronutrients – Phosphorus (P) • Uses in the plant: • Component of the energy molecules ATP and ADP. • These compounds serve to store and transfer available energy within the plant. • Structural constituent • Phospholipids • Phosphoproteins • Nucleic acids • Sugar phosphates • Nucleotides • Coenzymes

18. Macronutrients – Phosphorus (P) • Visual Symptoms of deficiency • Initially show up as reduced shoot growth and a dark green color. • As P deficiency continues, lower leaves may turn reddish at the leaf tips and then progress down the blade. • Stunted growth - caused by limited P for energy transformations. • Element of impairment Photo credit: Rosa Say

19. Macronutrients – Phosphorus (P) • Applications should be based on soil/tissue test results

20. Macronutrients – Potassium (K) • Taken up and stored as the ionic (K+) form. • Shoot tissue concentration of 1.0 to 3.0% by weight. • Used in the plant: • Enzymes activator • Most important solute in the vacuole • Osmoregulation = water regulation in plants • Used in carbohydrate, amino acid, and protein synthesis

21. Macronutrients – Potassium (K) • Visual symptoms of deficiency • Interveinal yellowing of older leaves (lower), followed by dieback of leaf tip, scorching or firing of the margins, and total yellowing of the leaf blade including the veins. • May appear weak or spindly. • Under high evaporative demand, wilting and leaf firing may be accelerated as well as wear injury in high traffic areas.

22. Macronutrients – Potassium (K) • Deficiencies result in: • Increased respiration and transpiration • Reduced environmental stress tolerance • Increased disease incidence • General reductions in growth

23. Bottom Line We must maximize our benefit of management practices to ensure a safe, enjoyable facility for our customers

24. Nitrogen Fate • What are some of the potential fates for N applied to a turf surface? • Taken up by grass • Microorganisms • Denitrification • Volatilization • Leaching

25. Sources of Nitrogen • Fertilizer • Returned Clippings • Organic Matter • Lightning (precipitation)

26. Consider the Whole System! • What can you change in your current system to further reduce N need? • Mowing • Irrigation • Fertilization • Equipment repair/replacement • Inventory management • Employees

27. Mowing/Maintenance • Increase mowing height • Increase root depth and photosynthetic capacity • Reduce highly maintained areas • Reducing fairway width/length to emphasize landing areas • Reduce/Eliminate flower beds/ornamentals • Fairways vs roughs

28. Seasonal Growth

29. Irrigation • Conduct irrigation audit • Ensure application rate/amount does not exceed infiltration • Match irrigation to weekly ET rates, accounting for rainfall received • On-site weather station • http://fawn.ifas.ufl.edu • Irrigation + rainfall should not wet profile below rootzone, only refill it!

30. Soil Compaction • Compacted soils • Reduced pore space = reduced root growth = reduced N uptake • Decreased infiltration increases risk of runoff • Monitor compaction, vary method/depth of aerfication

31. Consider Your Fertilizer Material

32. Quickly Available N • Very soluble • Rapid response • Short response • Cheap • Minimal temperature dependency • High leaching potential • Tendency to burn

33. Quickly Available N • Ammonium nitrate 33-0-0 • Ammonium sulfate 21-0-0 • Ammonium phosphates • mono-ammonium phosphate 11-48-0 • di-ammonium phosphate 20-50-0 • Potassium nitrate 13-0-44 • Urea (organic?) 46-0-0

34. Slow Release Nitrogen Sources • Slow initial response • Longer response than quick release • Some, but not all, are dependent on temperature for N release • Low burn potential • Moderately expensive to expensive • Less N leaching

35. Why Use Slow Release Fertilizers? • More uniform growth response • No growth surge • Longer growth response • Less chance of burn • Less leaching of nitrate • Labor saving

36. Uncoated Slow Release Fertilizers • Urea formaldehyde (UF) • Methylene urea (MU) • Isobutylidene diurea (IBDU) • Natural organics

37. Ureaform and Methylene Urea • Very similar materials chemically • Mostly granular, some liquids • about 40% N, 70% WIN (28% N for liquids, all soluble) • Formed by reacting urea and formaldehyde = chains of alternating C and N • Main difference is chain length, and as a result, mineralization rate

38. Products • Formolene 30-0-2 • FLUF 18-0-0 • Nitro 26 CRN 26-0-0 • Nitroform (Powder Blue, Blue Chip) 38-0-0 • CoRoN 28-0-0 • (25% of total N is urea)

39. Methylene Urea N-C-N N-C-C-C N-C-C-C-C N-C-C-C-C-C-C-C Urea Formaldehyde N-C-N N-C-C-C-C-C-C-C N-C-C-C-C-C-C-C-C-C N-C-C-C-C-C-C-C-C-C-C-C-C N-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C Different Chain Lengths

40. Ureaform and Methylene Urea • Designed to release N for 8-12 weeks • Contains unreacted urea, fast greening • Requires soil microbial activity • temperature sensitive, soil at 78o F is four times as active as soil at 42o F • moisture sensitive • Seasonal response

41. Nitroform • Urea formaldehyde • Insoluble organic • 38% N; 65-71% WIN • Biological N release • Rate influenced by soil temperature

42. Nutralene • Methylene urea • 40% N; 38% WIN • Biological N release • More rapidly available than UF • Not as adversely influenced by cool temperatures

43. IBDU • Urea is reacted with isobutyraldehyde • Only a single chemical product is formed, not a bunch of different molecules. 31% N, 90% WIN • Different sized granules available • N release depends on solubility and hydrolysis (IBDU molecule reacts with water and breaks apart), releasing urea. • No free urea in IBDU, may need to add

44. IBDU • Urea breaks down quickly to NH4 • IBDU is relatively insoluble, so only small amounts are available at any one time • Release sensitive to soil moisture, less on dependant on temperature • Release also depends on granule size and contact with soil. Smaller granules release N faster than larger granules

45. IBDU • 31% N -90% WIN • N released by hydrolysis • Relatively unaffected by • Temperature • pH • Particle size important • Excellent cool season response

46. Liquid Slow Release Fertilizers • Chemistry similar to UF, MU • Micro-suspension of MU (FLUF) • CoRoN, N-Sure; 28%N, 7% as urea and 21% as short chain MU or small ring structure. • Get quick and slow release • Foliar application? • Is slow release slow enough?

47. Liquid Slow Release Fertilizers • Easily handled, applied • Can be formulated with P and K • Some have short storage life • Require specialized delivery system • Volume of liquid used in application is not enough to move the material down into the root system - must irrigate in

48. CoRon • 28% N solution • Polymethylene ureas and amine modified polymethylene ureas • N release dependent upon microbial action

49. N-Sure • 30% N • Ring structured Triazones may contain methylene diurea • N release by microbial action • Response very similar to CoRon

50. Coated Slow Release Fertilizers • SCU, sulfur coated urea • Polymer coated urea • Poly Coated Sulfur Coated Urea