1. III.Fertilizing Forages Dennis Hancock, PhD. Extension Forage Specialist UGA – Dept. of Crop and Soil Sciences Dennis Hancock, PhD. Extension Forage Specialist UGA – Dept. of Crop and Soil Sciences

3. Plant Nutrients ElementAvailable Form OxygenO 2, OH - CarbonC0 3 -2, HCO 3, CO 2 HydrogenH +, OH - NitrogenNO 3 -, NH 4 + PhosphorusHPO 4 -2, H 2 PO 4 - PotassiumK+K+ Macro- (Primary) ElementAvailable Form CalciumCa +2 MagnesiumMg +2 SulfurSO 4 -2 Meso- (Secondary) ElementAvailable Form IronFe +2, Fe +3 CopperCu +2, Cu + ZincZn +2 ManganeseMn +2, MnO 4 - MolybdenumHMoO 4 -, MoO 4 -2 BoronH 3 BO 3, B 4 O 7 -2 ChlorineCl - Micro- (Trace)

4. Nutrients in Forage Plants Nitrogen – Chlorophyll, proteins, nucleic acids (DNA, RNA) Phosphorus – Cell nuclear proteins, cell division, energy transfer, root growth, plant maturity, fruiting and seed production Potassium – Enzyme activity, stress tolerance, water balance, cell division, carbohydrate formation Nitrogen – Chlorophyll, proteins, nucleic acids (DNA, RNA) Phosphorus – Cell nuclear proteins, cell division, energy transfer, root growth, plant maturity, fruiting and seed production Potassium – Enzyme activity, stress tolerance, water balance, cell division, carbohydrate formation

5. Nutrients in Forage Plants Calcium – Critical to cell division, cell membranes Magnesium – Chlorophyll, enzyme activation Sulfur – Part of three amino acids (proteins) Boron – Cell growth, legume roots/nodule function Calcium – Critical to cell division, cell membranes Magnesium – Chlorophyll, enzyme activation Sulfur – Part of three amino acids (proteins) Boron – Cell growth, legume roots/nodule function

6. Liebig’s Law of the Minimum Fe Cl Ca N Mg K P Mn Mo SZn Cu B

7. K is for Persistence

8. Potash also helps to ward off diseases and prepare for dormancy Leafspot and winterhardiness

9. K is the Key to a Good Stand

10. “Lime is the cheapest fertilizer there is.”

11. How Soil pH Affects Availability of Plant Nutrients

12. Organic Matter How Soil Holds Nutrients Ca 2+ K+K+ Mg 2+ Al 3+ K+K+ Mg 2+ Soil Particle CEC = 10 Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ Ca 2+ K+K+ Mg 2+ K+K+ CEC = 200

13. Ca 2+ K+K+ Mg 2+ H+H+ Al 3+ H+H+ CaCO 3 pH = 4.5 Soil Ca 2+ + CO 3 Soil + HCO 3 + Al(OH) 3 pH = 6.5

14. Low Soil pH

15. Low Soil pH = Aluminum Toxicity

16. Lime Quality Sieve Size% of total ≤ 10 mesh12 10-20 mesh17 20-35 mesh55 ≥ 35 mesh16 Rule: At least 90% must pass a 10 mesh sieve.

17. Lime Quality Affects Neutralizing Time

18. Thou Shalt Soil Test Sample 1/3 of your pastures each year. Sample hayfields every year.

19. Thou Shalt Soil Test Most common cause of poor establishment:  Soil pH and/or fertility is too low. Most common cause of poor persistence:  Soil pH and/or fertility is too low. Most common cause of poor drought tolerance:  Soil pH and/or fertility is too low. Most common cause of poor establishment:  Soil pH and/or fertility is too low. Most common cause of poor persistence:  Soil pH and/or fertility is too low. Most common cause of poor drought tolerance:  Soil pH and/or fertility is too low.

20. “Add only what is needed”

21. Fertilizer Bag Guaranteed Analysis19-19-19 Total Nitrogen (N)………………………………………………………………… 19.00% 10.6% Ammoniacal Nitrogen 8.4% Urea nitrogen Available Phosphoric Acid(P 2 O 5 ) …………………………………………………. 19.00% Soluble Potash (K 2 O)……………………………………………………………….. 19.00% Sulphur (SO 4 ) ………………………………………………………………………. 12.00% Calcium (Ca) ……………………………………………………………………….. 0.05% Magnesium (Mg) ………………………………………………………....…….…... 0.04% Boron (B)……………………………………………………………………………. 0.01% Copper (Cu)…………………………………………………………………………. 0.02% Iron (Fe)…………………………………………………………………………….. 0.10% Total Manganese (Mn)……………………………………………………………… 0.02% Molybdenum (Mo)……………………………………………………………….... 0.0005% Zinc (Zn)…………………………………………………………………………….. 0.05%

22. Hybrid Bermudagrass Yield Response to N Rate Hybrid Bermudagrass Yield Response to N Rate Average or “Normal” Response

23. Hybrid Bermudagrass Yield Response to N Rate Yield Limitations -Drought, low fertility, etc. -Inefficient application timing -Less effective N source

24. Hybrid Bermudagrass Yield Response to N Rate Hybrid Bermudagrass Yield Response to N Rate

25. SPLIT YOUR NITROGEN APPLICATIONS! Long-term, this can increase yields by 1200-2400 lbs/acre and increase NUE by 25-30%  Especially important under extremes  Leaching  Volatilization (in the case of urea-based products)  Late freeze  Drought

26. Other Common Nitrogen Sources Nitrogen Source ContentApprox. CCE* Ammonium Nitrate 34-0-0-61 Amm. Sulfate 21-0-0-24-110 Anhyd. Ammonia** 82-0-0-148 UAN Solution 32% (35% U + 45% AN) 32-0-0-55 28% (30% U + 40% AN) 28-0-0-49 Urea 46-0-0-81 Urea (Sulfur-coated) 38-0-0-16-118 Poultry Litter 3-3-2~10 * Approximate CaCO 3 (limestone) equivalent per 100 lb of product. For example, it will take 61 lbs of pure lime to neutralize the acidifying effect that ammonium nitrate has on the soil. ** Must be injected into the sod. Not recommended for bermudagrass production.

27. The Effectiveness of Some Alternative N Sources at Low, Medium, and High Fertilization Rates on Hybrid Bermudagrasses (Relative to Ammonium Nitrate). Nitrogen SourceFertilization Rates < 200 lbs*250-350 lbs> 400 lbs Ammonium Nitrate 100% Amm. Sulfate 95-97%95-105%60-70% Anhyd. Ammonia 92-94%93-95%94-95% UAN Solution 70-75%85-92%92-95% Urea 79-82%82-92%88-93% * Actual lbs of N per acre per year. Source: Burton and Jackson, 1962; Silveria et al., 2007.

28. Alternative N Sources Take-home message: If you have to use a urea-based product, be careful about cutting your rate back too much. -They are relatively less effective at low rates.

29. Poultry Litter for Hay Fields Weed pressure does increase  Not a source of weed seed  Changes the fertility and makes broadleaf weeds more competitive. Potassium fertilization may not be adequate  Poultry Litter: 3-3-2  Ideal bermudagrass fertilizer: 4-1-3 May result in excessive sulfur levels  Some evidence for a link to copper deficiency in cattle.

30. Too much of a good thing?

31. Resources

32. www.georgiaforages.com QUESTIONS?