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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
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Hybrid Bermudagrass Hay – 2008 Cost Breakdown
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14-15% From ‘08
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40% From ‘08
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Get a Grip on Your Forage Costs
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Fertilizer ^ $0.80 - $0.70 - $0.60
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Outline Overview of Soil Fertility Rewards and Risks when Fertilizing Forages Animal Manures Commercial Fertilizer “Enhanced Efficiency” Fertilizer Products (Nutrisphere, Agrotain, etc.)
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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)
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Nutrients Removed/Acre With Bermudagrass Hay or Corn Silage
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Soil Test and Follow Fertility Recommendations Sample hayfields every year and 1/3 of your pastures each year.
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Don’t plug ‘em up, just yet…
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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
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Liebig’s Law of the Minimum Fe Cl Ca N K P Mn Mo SZn Cu B Mg
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Hybrid Bermudagrass Yield Response to N Rate Hybrid Bermudagrass Yield Response to N Rate Average or “Normal” Response
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Hybrid Bermudagrass Yield Response to N Rate Hybrid Bermudagrass Yield Response to N Rate
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A Closer Look at Bermudagrass Yield Response to N Rate A Closer Look at Bermudagrass Yield Response to N Rate
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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
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A Closer Look at Bermudagrass Yield Response to N Rate N Applied During the Season (lbs actual N/acre) Eatonton 2007 (Drought Year)
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N Fertilizer Applications: Chemistry Ammonium NitrateUrea Uric Acid
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N Fertilizer Applications: Chemistry Ammonium Nitrate NH 4 + - -- - N0 3 -
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N Fertilizer Applications: Chemistry R-(NH 2 ) 2 (Urea, Uric Acid, etc.) + H 2 0 urease 2NH 3 2NH 4 + + 2H +
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N Application Strategies MAMJJASO Green-up Only
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N Application Strategies MAMJJASO Green-up Only
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N Application Strategies MAMJJASO Green-up & After 2 nd Cut
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N Application Strategies MAMJJASO Green-up & After 2 nd Cut
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N Application Strategies MAMJJASO Green-up & After Each Cut
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N Concentration in the Forage Crop Days of Growth Growth of the Crop Nitrate Conc. in the Crop
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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
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N Concentration in the Forage Crop Days of Growth Nitrate Conc. in the Crop 5000 ppm Drought
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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
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Monitor Climate Predictions http://www.cpc.ncep.noaa.gov/
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Monitor Climate Predictions http://www.cpc.ncep.noaa.gov/products/predictions/90day/
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A Closer Look at Bermudagrass Yield Response to N Rate N Applied During the Season (lbs actual N/acre) Eatonton 2007 (Drought Year)
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A Closer Look at Bermudagrass Yield Response to N Rate A Closer Look at Bermudagrass Yield Response to N Rate Eatonton 2007
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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!
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Fertilization Strategies New N Fertilizer Products
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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
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Nitrogen Use Efficiency Eatonton Calhoun 2008
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Nitrogen Use Efficiency Eatonton 2008
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New N Products ? ?
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Get a Grip on Your Forage Costs Fertilizer ^ $0.80 - $0.70 - $0.60
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Another Fertilization Trick Apply P in late summer or fall. P can essentially be applied any time during the year on established forage crops. Purchase P fertilizer in “off-peak” times of the year (i.e., summer and fall) Demand for the product is low Demand for spreading services is low Less risk of P runoff P can essentially be applied any time during the year on established forage crops. Purchase P fertilizer in “off-peak” times of the year (i.e., summer and fall) Demand for the product is low Demand for spreading services is low Less risk of P runoff
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Another Fertilization Trick Split Your Potassium Applications! 40-50% in the Spring 50-60% in mid – late season
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Potash also determines competitiveness in bermudagrass Leafspot and winterhardiness
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Poor Stress Tolerance Leafspot Diseases The Stand is Gone! Not Competitive Grows Very Slow Poor Winterhardiness K is for Persistence
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K is the Key to a Good Stand
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Increase Corn Grain Dries down slower Later Maturing K Effects on Corn Silage Faster Body Weight Recovery
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DO NOT cut back on lime! Get your priorities right! 1.Lime is still job #1. Get your priorities right! 1.Lime is still job #1.
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How Soil pH Affects Availability of Plant Nutrients The Difference of a soil pH of 5.8 vs. 6.2 Nutrient Amt. Used Annually Unit Price Dec. in Efficiency Value of Decrease (Lbs/acre)($/lb)($/acre) N200$0.8520% -$34 P2O5P2O5 50$0.8025% -$10 K2OK2O150$0.6010% -$ 9 Total -$53
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What’s a Common Soil pH Value S. Piedmont
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Fertilization Strategies Hayfield 2 & 3 pH = 5.5 P = 15 K = 90 OM = 1.5% Hayfield 2 & 3 pH = 5.5 P = 15 K = 90 OM = 1.5% Hayfield 1 pH = 6.0 P = 25 K = 120 OM = 2.5% Hayfield 1 pH = 6.0 P = 25 K = 120 OM = 2.5%
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Costs Increase When Soil Fertility Decreases Recommended Rate of P & K Fertility NP2O5P2O5 K2OK2O Total Cost ------------- (lbs/acre) -------------($/acre) V. High 25000$187.50 High 25030150 318.59 Medium 25060200 352.17 Low 25080250 439.57 Assumptions: Using 32% UAN ($480/ton), DAP ($1300/ton), and Muriate of Potash ($780/ton). Let’s assume P & K have been equally taken care of or equally neglected. So, let’s consider bermudagrass fertility.
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If you must cut back… Do so uniformly! If the recommendation is for N, P, and K, be sure to apply each. Don’t just apply N!!! IMPORTANT Do a total reduction (by a percentage). Base the reduction in P and/or K off of the N reduction If you reduce N by 20% from the Rec. Rate… Then reduce the other recommended rates by 20% EXCEPTION: If your soil is “Very Low.” Do so uniformly! If the recommendation is for N, P, and K, be sure to apply each. Don’t just apply N!!! IMPORTANT Do a total reduction (by a percentage). Base the reduction in P and/or K off of the N reduction If you reduce N by 20% from the Rec. Rate… Then reduce the other recommended rates by 20% EXCEPTION: If your soil is “Very Low.”
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Costs Increase When Soil Fertility Decreases Recommended Rate of P & K Fertility NP2O5P2O5 K2OK2O Total Cost ------------- (lbs/acre) -------------($/acre) V. High 20000$150.00 High 20024120 254.87 Medium 20048160 307.74 Low 20064200 351.65 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%.
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Broiler Numbers Layer Numbers A Major Fertility Advantage
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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: 3-3-2 Ideal bermudagrass fertilizer: 4-1-3
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Variability in Chicken Litter “Book Number” 3-3-2 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” 3-3-2 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.
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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)
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Doing Many Things Well F F F F F F F A F
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Nutrients Removed/Acre With Bermudagrass Hay or Corn Silage
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Nutrients removed per acre in a typical weaned beef calf. Adapted from S. Forages 3 rd Ed.
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Efficiency of Four-legged Manure Spreaders White et al., 2001 J. Environ. Qual. 30:2180–2187
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Nutrient Distribution in Pastures
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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%
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QUESTIONS? www.georgiaforages.com 1-800-ASK-UGA1
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