2008 Hay Production School
Fertilization Strategies for Hay Producers
Questions to be addressed:
• What nutrients are essential for high yields/quality?
• What is “goin’ on” with the fertilizer market?
Fertilization Strategies for
Hay Producers
• How do I get the most out of my fertilizer?
• What are UGA recommendations for N?
• What are the differences between N fertilizer products?
• What are the implications for using poultry litter (or
other wastes) as my main source of fertility?
Dennis Hancock, PhD.
Extension Forage Specialist
UGA – Dept. of Crop and Soil Sciences
Plant Nutrients
Liebig’s Law of the Minimum
Macro- (Primary)
Micro- (Trace)
Element
Available Form
Element
Available Form
Oxygen
O2, OH-
Iron
Fe+2 , Fe+3
-2,
Carbon
C03
Copper
Cu+2
Hydrogen
H+, OH-
HCO3 , CO2
Zinc
Zn+2
,
Nitrogen
NO3- , NH4+
Manganese
Mn+2 , MnO4-
Phosphorus
HPO4-2, H2PO4-
Molybdenum
HMoO4- , MoO4-2
Potassium
K+
Boron
H3BO3, B4O7-2
Chlorine
Cl-
S Mo
Cu
Zn
Mn
P
Fe
Cl
Cu+
B
Mg
Ca
K
N
Meso- (Secondary)
Element
Available Form
Calcium
Ca+2
Magnesium
Mg+2
Sulfur
SO4-2
K is for Persistence
Potash also helps to ward off
diseases and prepare for dormancy
Leafspot and winterhardiness
Dr. Dennis Hancock
Extension Forage Agronomist
1
2008 Hay Production School
Fertilization Strategies for Hay Producers
High Fertilizer Prices Are
Probably Here To Stay
K is the Key to a Good Stand
• Inorganic N fertilizer is directly tied
to the energy (natural gas) market.
ƒ Haber-Bosch process (N2 -> NH3)
ƒ High international demand
ƒ Cheap dollar on the world market
• Potassium is no longer the cheap
nutrient it once was.
ƒ
ƒ
ƒ
ƒ
Potassium Production/Consumption - 2006
High international demand
It is mostly an international product
Production had been reined-in
Mine failures (flooding, particularly in
Eastern European countries)
Get the most out of your
fertilizer bill…
U.S.
< 2.0
Soil test each hayfield each year!
“Add only what is needed”
“Lime is the cheapest fertilizer there is.”
Dr. Dennis Hancock
Extension Forage Agronomist
2
2008 Hay Production School
Fertilization Strategies for Hay Producers
How Soil pH Affects Availability of Plant Nutrients
Low Soil pH = Aluminum Toxicity
Low Soil pH
CaCO
3
Lime Quality
CaCO3
Rule: At least 90% must
pass a 10 mesh sieve.
Ca2+ + CO3
pH = 4.5
Mg2+
H+
Soil
Soil
Al3+
Al3+
Ca2+
Al3+
Ca2+
H+
Ca2+
HCO3 + Al(OH)3
+
Sieve Size
K+
pH = 6.5
Dr. Dennis Hancock
Extension Forage Agronomist
3
% of total
≤ 10 mesh
12
10-20 mesh
17
20-35 mesh
55
≥ 35 mesh
16
2008 Hay Production School
Fertilization Strategies for Hay Producers
Hybrid Bermudagrass Yield
Response to N Rate
Lime Quality Affects Neutralizing Time
14.0
12.0
Average or “Normal” Response
10.0
Forage Yield
(tons/A)
@15% moisture
8.0
6.0
4.0
2.0
0.0
0
100
200
300
400
500
600
700
800
Nitrogen Rate
(lbs N/A)
Hybrid Bermudagrass Yield
Response to N Rate
Hybrid Bermudagrass Yield
Response to N Rate
14.0
12.0
10.0
Forage Yield
(tons/A)
@15% moisture
8.0
6.0
Yield Limitations
- Drought, low fertility, etc.
- Inefficient application timing
- Less effective N source
4.0
2.0
0.0
0
100
200
300
400
500
600
700
800
Nitrogen Rate
(lbs N/A)
SPLIT YOUR NITROGEN APPLICATIONS!
Other Common Nitrogen Sources
Nitrogen Source
Ammonium Nitrate
Amm. Sulfate
Anhyd. Ammonia**
UAN Solution
32% (35% U + 45% AN)
28% (30% U + 40% AN)
Urea
• Long-term, this can increase yields by 1200-2400
lbs/acre and increase NUE by 25-30%
Urea (Sulfur-coated)
Poultry Litter
ƒ Especially important under extremes
¾ Leaching
¾ Volatilization (in the case of urea-based products)
¾ Late freeze
¾ Drought
*
Content
Approx. CCE*
34-0-0
-61
21-0-0-24
-110
82-0-0
-148
32-0-0
-55
28-0-0
-49
46-0-0
-81
38-0-0-16
-118
3-3-2
~10
Approximate CaCO3 (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.
Dr. Dennis Hancock
Extension Forage Agronomist
4
2008 Hay Production School
Fertilization Strategies for Hay Producers
The Effectiveness of Some Alternative N Sources at
Low, Medium, and High Fertilization Rates on Hybrid
Bermudagrasses (Relative to Ammonium Nitrate).
Nitrogen Source
Ammonium Nitrate
Amm. Sulfate
Anhyd. Ammonia
UAN Solution
Urea
Alternative N Sources
Fertilization Rates
< 200 lbs*
250-350 lbs
> 400 lbs
100%
100%
100%
95-97%
95-105%
60-70%
92-94%
93-95%
94-95%
70-75%
85-92%
92-95%
79-82%
82-92%
88-93%
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.
* Actual lbs of N per acre per year.
Source: Burton and Jackson, 1962; Silveria et al., 2007.
Too much of a good thing?
Poultry Litter for Hay Fields
• Weed pressure does increase
ƒ Not a source of weed seed
ƒ Changes the fertility and makes
broadleaf weeds more competitive.
• Potassium fertilization may not be
adequate
ƒ Poultry Litter: 3-3-2
ƒ Ideal bermudagrass fertilizer: 4-1-3
• May result in excessive sulfur levels
ƒ Some evidence for a link to copper
deficiency in cattle.
Resources on CD
Fertilization Strategies for
Hay Producers
QUESTIONS?
www.georgiaforages.com
Dr. Dennis Hancock
Extension Forage Agronomist
5