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 ?