Soil and Fertilizer Management Considerations for Forage Systems in GA Dennis Hancock, PhD. Extension Forage Agronomist UGA – Dept. of Crop and Soil Sciences Dennis Hancock, PhD. Extension Forage Agronomist UGA – Dept. of Crop and Soil Sciences

Hybrid Bermudagrass Hay – 2008 Cost Breakdown

14-15% From ‘08

40% From ‘08

Get a Grip on Your Forage Costs

Fertilizer ^ $ $ $0.60

Outline Overview of Soil Fertility Rewards and Risks when Fertilizing Forages  Animal Manures  Commercial Fertilizer  “Enhanced Efficiency” Fertilizer Products (Nutrisphere, Agrotain, etc.)

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)

Nutrients Removed/Acre With Bermudagrass Hay or Corn Silage

Soil Test and Follow Fertility Recommendations Sample hayfields every year and 1/3 of your pastures each year.

Don’t plug ‘em up, just yet…

What is holding back hay yields? Drought Low Soil pH Inefficient N application methods Inefficient N application methods Less effective N sources Less effective N sources Low K fertility Insect Damage

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

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

Hybrid Bermudagrass Yield Response to N Rate Hybrid Bermudagrass Yield Response to N Rate

A Closer Look at Bermudagrass Yield Response to N Rate A Closer Look at Bermudagrass Yield Response to N Rate

The False Economy of Shortcuts Cost of Production Compared to Average Yield (t/ac)60%75%90%100%110%125% 8$56$71$85$94$103$118 7$64$80$96$107$118$134 6$75$94$113$125$138$156 5$90$113$135$150$165$188 4$113$141$169$188$207$235 3$150$188$225$250$275$313 Adapted from R.C. Lacy, 2008

A Closer Look at Bermudagrass Yield Response to N Rate N Applied During the Season (lbs actual N/acre) Eatonton 2007 (Drought Year)

N Fertilizer Applications: Chemistry Ammonium NitrateUrea Uric Acid

N Fertilizer Applications: Chemistry Ammonium Nitrate NH N0 3 -

N Fertilizer Applications: Chemistry R-(NH 2 ) 2 (Urea, Uric Acid, etc.) + H 2 0 urease 2NH 3 2NH H +

N Application Strategies MAMJJASO Green-up Only

N Application Strategies MAMJJASO Green-up Only

N Application Strategies MAMJJASO Green-up & After 2 nd Cut

N Application Strategies MAMJJASO Green-up & After 2 nd Cut

N Application Strategies MAMJJASO Green-up & After Each Cut

N Concentration in the Forage Crop Days of Growth Growth of the Crop Nitrate Conc. in the Crop

N Concentration in the Forage Crop Days of Growth Nitrate Conc. in the Crop 5000 ppm Rec. Rate 2 x Rec. Rate 3 x Rec. Rate

N Concentration in the Forage Crop Days of Growth Nitrate Conc. in the Crop 5000 ppm Drought

N Concentration in the Forage Crop Days of Growth Nitrate Conc. in the Crop 5000 ppm Rec. Rate 2 x Rec. Rate 3 x Rec. Rate

Monitor Climate Predictions

Monitor Climate Predictions

A Closer Look at Bermudagrass Yield Response to N Rate N Applied During the Season (lbs actual N/acre) Eatonton 2007 (Drought Year)

A Closer Look at Bermudagrass Yield Response to N Rate A Closer Look at Bermudagrass Yield Response to N Rate Eatonton 2007

A Fertilization Trick Long-term, this can increase yields by 5-10% and increase NUE by 25-30%  Especially important under extremes  Leaching  Volatilization (in the case of urea-based products)  Late freeze  Drought Helps to prevent NITRATE TOXICITY! Split Your Nitrogen Applications!

Fertilization Strategies New N Fertilizer Products

Enhanced Efficiency Fertilizer Without AN, users of N face risky alternatives.  NH 3 volatilization loss Urease is abundant in thatch & organic layers  High N use in hay. Enhanced Efficiency N Fertilizer Products may reduce volatilization loss  Urease inhibition  Encapsulate & release Ammonium Nitrate Urea NBPT maleic-itaconic co-polymer Polymer Coating

Nitrogen Use Efficiency Eatonton Calhoun 2008

Nitrogen Use Efficiency Eatonton 2008

New N Products ? ?

Get a Grip on Your Forage Costs Fertilizer ^ $ $ $0.60

Another Fertilization Trick Apply P in late summer or fall. P can essentially be applied any time during the year on established forage crops. Purchase P fertilizer in “off-peak” times of the year (i.e., summer and fall)  Demand for the product is low  Demand for spreading services is low  Less risk of P runoff P can essentially be applied any time during the year on established forage crops. Purchase P fertilizer in “off-peak” times of the year (i.e., summer and fall)  Demand for the product is low  Demand for spreading services is low  Less risk of P runoff

Another Fertilization Trick Split Your Potassium Applications! 40-50% in the Spring 50-60% in mid – late season

Potash also determines competitiveness in bermudagrass Leafspot and winterhardiness

Poor Stress Tolerance Leafspot Diseases The Stand is Gone! Not Competitive Grows Very Slow Poor Winterhardiness K is for Persistence

K is the Key to a Good Stand

Increase Corn Grain Dries down slower Later Maturing K Effects on Corn Silage Faster Body Weight Recovery

DO NOT cut back on lime! Get your priorities right! 1.Lime is still job #1. Get your priorities right! 1.Lime is still job #1.

How Soil pH Affects Availability of Plant Nutrients The Difference of a soil pH of 5.8 vs. 6.2 Nutrient Amt. Used Annually Unit Price Dec. in Efficiency Value of Decrease (Lbs/acre)($/lb)($/acre) N200$0.8520% -$34 P2O5P2O5 50$0.8025% -$10 K2OK2O150$0.6010% -$ 9 Total -$53

What’s a Common Soil pH Value S. Piedmont

Fertilization Strategies Hayfield 2 & 3 pH = 5.5 P = 15 K = 90 OM = 1.5% Hayfield 2 & 3 pH = 5.5 P = 15 K = 90 OM = 1.5% Hayfield 1 pH = 6.0 P = 25 K = 120 OM = 2.5% Hayfield 1 pH = 6.0 P = 25 K = 120 OM = 2.5%

Costs Increase When Soil Fertility Decreases Recommended Rate of P & K Fertility NP2O5P2O5 K2OK2O Total Cost (lbs/acre) ($/acre) V. High 25000$ High Medium Low Assumptions: Using 32% UAN ($480/ton), DAP ($1300/ton), and Muriate of Potash ($780/ton). Let’s assume P & K have been equally taken care of or equally neglected. So, let’s consider bermudagrass fertility.

If you must cut back… Do so uniformly! If the recommendation is for N, P, and K, be sure to apply each.  Don’t just apply N!!! IMPORTANT  Do a total reduction (by a percentage). Base the reduction in P and/or K off of the N reduction  If you reduce N by 20% from the Rec. Rate…  Then reduce the other recommended rates by 20%  EXCEPTION: If your soil is “Very Low.” Do so uniformly! If the recommendation is for N, P, and K, be sure to apply each.  Don’t just apply N!!! IMPORTANT  Do a total reduction (by a percentage). Base the reduction in P and/or K off of the N reduction  If you reduce N by 20% from the Rec. Rate…  Then reduce the other recommended rates by 20%  EXCEPTION: If your soil is “Very Low.”

Costs Increase When Soil Fertility Decreases Recommended Rate of P & K Fertility NP2O5P2O5 K2OK2O Total Cost (lbs/acre) ($/acre) V. High 20000$ High Medium Low Assumptions: Using 32% UAN ($480/ton), DAP ($1300/ton), and Muriate of Potash ($780/ton). Let’s assume P & K have been equally taken care of or equally neglected. So, let’s consider bermudagrass fertility. Let’s cut back by 20%.

Broiler Numbers Layer Numbers A Major Fertility Advantage

Poultry Litter for Hay Fields An excellent source of fertility, when used wisely. N release is skewed to the summer months. 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:  Ideal bermudagrass fertilizer: 4-1-3

Variability in Chicken Litter “Book Number”  Range in % N  1.1 – 4.9% Range in % P 2 O 5  0.9 – 4.8% Range in % K 2 O  1.2 – 4.0% “Book Number”  Range in % N  1.1 – 4.9% Range in % P 2 O 5  0.9 – 4.8% Range in % K 2 O  1.2 – 4.0% Source: Univ. of Ark. Ext. Bulletin FSA-8000.

Foliar Fertilizer Applications Even if the product is 100% efficient (likely isn’t) The most a plant can take up will be 1-2 lbs of nutrients  Works for many micro-nutrients (small quantities needed)  Not feasible for macro-nutrients without multiple applications. (large quantities needed) Even if the product is 100% efficient (likely isn’t) The most a plant can take up will be 1-2 lbs of nutrients  Works for many micro-nutrients (small quantities needed)  Not feasible for macro-nutrients without multiple applications. (large quantities needed)

Doing Many Things Well F F F F F F F A F

Nutrients Removed/Acre With Bermudagrass Hay or Corn Silage

Nutrients removed per acre in a typical weaned beef calf. Adapted from S. Forages 3 rd Ed.

Efficiency of Four-legged Manure Spreaders White et al., 2001 J. Environ. Qual. 30:2180–2187

Nutrient Distribution in Pastures

Mechanical Hay30-70% Silage60-85% Green Chop70-95% Efficiencies of Grazing and Mechanized Harvest MethodEfficiency Grazing Continuous Stocking30-40% Slow Rotation (3-4 paddocks)50-60% Moderate Rotation (6-8 paddocks)60-70% Strip Grazing70-80%

QUESTIONS? ASK-UGA1