2014 Southeast Hay Convention
Fine Tuning Fertilization
in Your Hayfields
Fine-Tuning Fertilization
in Your Hayfields
Outline
• Fertilization Tips and Tricks
§  Increased nutrient use efficiency
• Tissue Sampling to Fine-Tune and
Troubleshoot
• Sounds too good to be true!
§  N fertilizer savings
§  Foliar fertilizers
Dr. Dennis Hancock
Extension Forage Specialist
Crop and Soil Sciences – UGA
A Fertilization Trick
N Application Strategies
Green-up Only
Split Your Nitrogen Applications!
(Common Strategy
with Poultry Litter)
•  Long-term, this can increase yields by 5-10% and
increase NUE by 25-30%
§  Especially important under extremes
Ø  Leaching
Ø  Volatilization (in the case of urea-based products)
Ø  Late freeze
Ø  Drought
•  Helps to prevent NITRATE TOXICITY!
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N Application Strategies
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Dr. Dennis Hancock
Extension Forage Agronomist
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N Application Strategies
Green-up & After 2nd Cut
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Green-up & After Each Cut
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2014 Southeast Hay Convention
Fine Tuning Fertilization
in Your Hayfields
Nitrogen Response:
Hybrid Bermudagrass Yield
Response to N Rate
Rules of Thumb
N Response Above Critical Level*
Forage Type
Early Season Mid-Season Late-Season
------- lb of DM/lb of N added -------
Coastal bermuda
30-45
35-45
20-35
Tifton 85 bermuda
30-40
45-55
30-40
Annual ryegrass
5-12
10-20
15-30
*
Fertilization Trick
Cost Implications of Different
Nitrogen Response Rates
$0.50
Nitrogen Response
lbs of DM/lb of N
5
10
15
20
25
30
35
40
45
50
55
N fertilization above an annual ~40, 50, or 25 lbs of N/acre for Coastal,
Tifton 85, and ryegrass, respectively.
Account for N Loss from Urea-based Products
Cost of N, $/lb of N
$0.60
$0.75
$1.00
N Cost of Additional Production
--------------------------- $/lb of DM ---------------------------
$0.100
$0.050
$0.033
$0.025
$0.020
$0.017
$0.014
$0.013
$0.011
$0.010
$0.009
$0.120
$0.060
$0.040
$0.030
$0.024
$0.020
$0.017
$0.015
$0.013
$0.012
$0.011
$0.150
$0.075
$0.050
$0.038
$0.030
$0.025
$0.021
$0.019
$0.017
$0.015
$0.014
$0.200
$0.100
$0.067
$0.050
$0.040
$0.033
$0.029
$0.025
$0.022
$0.020
$0.018
Use of Urea-Based Products
The Effectiveness of Some Alternative N Sources at
Low, Medium, and High Fertilization Rates on Hybrid
Bermudagrasses (Relative to Ammonium Nitrate).
• Without AN, users of N
face risky alternatives.
Nitrogen Source
• Urease is abundant in
thatch & organic layers
Ammonium Nitrate
Fertilization Rates
< 200 lbs*
250-350 lbs
> 400 lbs
100%
100%
100%
Amm. Sulfate
95-97%
95-105%
60-70%
Anhyd. Ammonia
UAN Solution
92-94%
93-95%
94-95%
80-85%
85-92%
92-95%
Urea
79-82%
82-92%
88-93%
Ammonium Nitrate
§  NH3 volatilization loss
NBPT
§  High N use in hay.
• Enhanced Efficiency N
Fertilizer Products may
reduce volatilization loss
* Actual lbs of N per acre per year.
Source: Burton and Jackson, 1962; Silveria et al., 2007.
Dr. Dennis Hancock
Extension Forage Agronomist
Urea
§  Urease inhibition
§  Encapsulate & release
2
Polymer
Coating
maleic-itaconic
co-polymer
2014 Southeast Hay Convention
Fine Tuning Fertilization
in Your Hayfields
Ammonia Volatilization Trap Data
Bermudagrass Hay Yield
2008 140 2008-2009 (Calhoun)
2009 2008 20,000 2009 120 100 15,000 (lbs/acre) Forage Yield (ppm) Ammonia (NH4-­‐N) Vola0liza0on 2008-2009 (avg. over two locations)
80 60 40 10,000 5,000 20 0 0 Urea ATU NSN ESN Urea ATU NSN ESN Another Fertilization Trick
Summary of EE N products
Apply P in late summer or fall.
Agrotain Treated Urea
as compared to urea applied in the same
way (averaged over 4 site-yrs):
•  Reduced ammonia volatilization by
over 63%.
•  Produced 11% more forage yield.
•  Recovered 19% more of the applied N.
•  Did not substantially affect crude
protein content.
•  Did not substantially affect the risk of
nitrate toxicity.
•  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
K is for Persistence
Split Your Potassium Applications!
Not Competitive
Leafspot Diseases
Poor Winterhardiness
Grows Very Slow
Poor Stress Tolerance
40-50%
in the Spring
The Stand is Gone!
50-60%
in mid – late season
Dr. Dennis Hancock
Extension Forage Agronomist
3
2014 Southeast Hay Convention
Fine Tuning Fertilization
in Your Hayfields
K is the Key to a Good Stand
Tissue Sampling and
Troubleshooting
Tissue Sampling
Troubleshooting
6 in.
Good Zones
• Tissue Sample
• Soil Sample
• Other(?)
Bad Zones
• Tissue Sample
• Soil Sample
• Other(?)
Representative Samples
• ~ 20 similar specimens
Chlorophyll and
Nutrient
Mg
N
H
C
Which is the better hay?
Dr. Dennis Hancock
Extension Forage Agronomist
O
4
2014 Southeast Hay Convention
Fine Tuning Fertilization
in Your Hayfields
Foliar Fertilization
for Forage Crops?
•  Over 50% of applied N
is absorbed in < 5 hrs.
•  But, this is at relatively
low rates
-  Avg. over 4.5 and 11 lbs of
N/acre in this study.
-  Stiegler et al., 2010. Crop
Sci. 51:1253-1260.
Photo credit: http://freakoutville.wordpress.com/2010/07/16/the-snake-oil-salesman/
•  Even if 60% absorption,
at rate of 11 lbs/acre,
that’s only 6.7 lbs of N
absorbed foliar.
Calculations Using 42-0-0
•  Five 25-lb bags/100 gallons of spray = 10 A
-  Highest rate of absorption I
could find in literature.
§  125 lbs of product/10 A or 12.5 lbs of product/A
§  12.5 lbs x 42% N = 5.25 lbs of N/A
•  At higher rates, foliar
fertilizers often burn (salt
or chemical injury) the plant
tissue
•  42% N x 25 lbs = 10.5 lbs of N
•  In a separate study
(Totten et al., 2008. J.
Plant Nutr. 31:972-982),
no consistent difference
in clipping yield of turf.
•  $47/bag / 10.5 lbs of N = $4.48 per lb of N
•  Ammon. Nitrate is currently ~$0.70 per lb of N
Their 42-0-0 is Straight Urea!
Calculations Using 42-0-0
•  Let’s assume 4 applications of 75 lbs of N/acre
§  Conventional: 4 x 75 lbs x $0.70/lb= $210
Ø  Plus: spreading costs
§  Liquid product (their rate): 4 x 5.25 lbs x $4.48/lb = $94
§
“
(rec. N rate): 4 x 75 lbs x $4.48/lb = $1344
Ø  Plus: water and spreading costs
•  1-ton of bermudagrass, @ 1.6% N = 32 lbs of N
Bottomline: their math doesn’t add up
(5.25 < 32).
Dr. Dennis Hancock
Extension Forage Agronomist
5
2014 Southeast Hay Convention
Fine Tuning Fertilization
in Your Hayfields
Foliar Fertilizer Applications
•  Even if the product is 100% efficient (likely isn’t)
•  The most a plant can take up across via the leaves is
the equivalent of 10-12 lbs/acre of the nutrient
§  Works for many micro-nutrients (small quantities needed)
§  Not feasible for macro-nutrients without multiple
applications. (large quantities needed)
www.georgiaforages.com
Dr. Dennis Hancock
Extension Forage Agronomist
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