Nitrogen Sources for Cotton Across the Belt
Glen Harris – UGA (Tifton)
Ammonium Nitrate vs. Urea
For Cotton Production in Georgia
Glen HarrisUniversity of Georgia (Tifton)
Nitrogen Sources for 2007
Glen HarrisUGA - Tifton
Industrial N Fixation
Haber Bosch Process N2 + 3H2 >>>>>>> 2NH3
Heat + Pressure
Natural Gas = Ingredient + Fuel Source
CaNO3 ?KNO3 ?Source: PPI Soil Fertility Manual
Choosing an N Source for Cotton
“All sources of nitrogen are considered equal in their ability to provide nitrogen to cotton. No one form of nitrogen is superior to another if all are applied correctly. Base choices on price, availability and ease of application”
Mississippi State University Extension Service
Nitrogen Source Comments
Anhydrous Ammonia Gas
Inexpensive
Safety/Dealer Insurance
Methamphetamines
UAN Solutions Liquid
Urea+Ammonium+Nitrate
Urea Solid
Concentrated
Volatilization
Ammonium Nitrate Regulations
Availability
Higher Cost
Comparing Nitrogen Fertilizers
18
18
34
194
26
0
20
40
60
80
100
120
140
160
180
200
Anhy AS Urea AN N Soln DAP?
Nitrogen Fertilizers Sold in Georgia – FY 06 (Tons x 1000)
50
40
51
47 48
43
34
0
10
20
30
40
50
60
2000 2001 2002 2003 2004 2005 2006
Ammonium Nitrate Sold in Georgia (Tons x 1000)
11
14
1213
1615
18
0
2
4
6
8
10
12
14
16
18
2000 2001 2002 2003 2004 2005 2006
Urea Sold in Georgia (Tons x 1000)
Ammonium Nitrate Urea
Solid Solid
34 % N 46 % N
Salt Index=105 Salt Index=75
Safety/Regulations
Availability
Volatilization
$315/ton
$0.46/lb N
$345/ton
$0.38/lb N
The Comparison
Has Urea Gotten a Bum Rap ?
• Worst Case Scenerio Loss = 30 %
• Not as Good as Ammonium Nitrate ?
• Not as “Quick” as Ammonium Nitrate ?
0
200
400
600
800
1000
1200
UTC CRN CRN2 FolN Urea UAN 28S Nitam AN AS
Yields (lb lint/a)Late Sidedress N Source – Expo 2005
ee
de
d
c c
bc
ab ab
a
Conditions that lead to NH3 loss• Enough soil water for hydrolysis, but not enough to leach urea into soil• Low pH buffering capacity (low OM)• High temperatures• High wind speed
CO(NH2)2 + 2H2O + H+ 2NH4+ + HCO3-
urea urease
clayOM
--- NH4+ NH4+aq NH3 aq + H+
NH3 gas
NH3 gas
How To Limit Volatilization Losses from Urea
• Incorporate Into Soil with Tillage• Inject Beneath Soil Surface• Apply in a Band• Apply When Soil Temp Below 50 F• Irrigate Shortly After Application• Pray for Rain on Dryland• Use a Urease Inhibitors
– Ex. Agrotain
Fertilizer additive that inhibits degradation of urea by urease
Urease = enzyme produced by soil microbes
Does not affect microbes (or other soil organisms) directly
Reduces loss of surface applied urea-N to volatilization
14-Day Inhibition period – rapid drying conditions
N-(n-Butyl) –thiophosphoric triamide aka NBPT
0
5
10
15
20
25
30
35
40
45
<3 <7 <14 >14
Urea
UAN
Net Return ($/a) by “Rain-Free Days”
# of Rain-Free Days
Evaluation of a Urease Inhibitor with Sidedress Nitrogen in the Southeast
Glen HarrisUniversity of Georgia - Tifton
AGROTAIN vs. N-Serve
Urease Inhibitor Nitrification Inhibitor
• ESN = Environmentally Smart Nitrogen• Polymer Coated Urea• Company = Agrium• “Controlled Release”• “Releases as the Soil Warms”• Corn in Ohio and Canada (+ Kentucky) • Cotton in Georgia - 2006
Split Applications vs. Slow Release
555580
674
750
683
752731
689 681
0
100
200
300
400
500
600
700
800
0 30SR 60SR 90SR
Yields (lb lint/a)2006 ESN vs. NitrateSunbelt Expo (Moultrie, GA)
30SR60AN
30AN60SR
30SR30SR
30AN60AN
30SR60SR
1727
2147 21992102 2115
0
500
1000
1500
2000
2500
0
Yields (lb lint/a)2006 ESN vs. UreaSunbelt Expo (Moultrie, GA)
30SR30U
30U30SR
30SR30SR
30U30U
“Enhanced Efficiency (EE)” FertilizersNew Term Coined by The Fertilizer Institute (TFI)
Slow/Controlled ReleaseAbsorbedCoatedOccludedReacted
Stabilized/AdditiveNitrification InhibitorsUrease InhibitorsStabilizers
Association of American Plant Food Control Officials (AAPFCO)
“…products that minimize the potential of nutrient loss to the environment.”
1250
1535
13941472
1517 1493
0
200
400
600
800
1000
1200
1400
1600
Yields (lb lint/a)2006 Tetra UAN/CaClSunbelt Expo
0 UAN0 CaCl
0 UAN+CaCl
30 UAN 30 UAN+CaCl
60 UAN 60 UAN+CaCl
1250
1394
15771517
1632
0
200
400
600
800
1000
1200
1400
1600
1800
0
Yields (lb lint/a)2006 Englehard/Attapulgite ClaySunbelt Expo
30 UAN 30 Clay 60 UAN 60 Clay
Poultry LitterThe “Original” Slow Release Fertilizer
(+ Biosolids and Legume Cover Crops ?)
Time for Questions ?
Top Related