Glen Harris – Extension Agronomist
Environmental Soils & Fertilizers
1994-2000 (aka “The Good ‘ol Days”)
100 % Extension
2, 100% Soil Fertility Researchers in Tifton
2, 100 % Soils Extension Specialists in Athens
Travel Money and Lottery Money
Program Emphasis:
Basic Soil Fertility
Cotton
Poultry Litter
Conservation Tillage
2000 – 2010 Timeline*
2001 – Chair, Southern Soil Fertility Conference
2002 - US-AID Peanut CRSP Guyana
2003 - Study Leave, CSIRO Australia
- Charter Class, UGA Tifton, Soils & Hydrology
- Chair, Soil and Plant Nutrition Conference at Cotton Beltwide
2004 - Urease Inhibitors
- “Winter Meetings” in Guyana
2005 – Chair, ASA A-4 Extension Education
- College Conservation Tillage Task Force
2007 - 2008 – China
2009 - 2010 – Calcium on Peanut and Potassium on Cotton
* Lost 2 Soil Researchers, 2 Soil Extension Specialists, Soil Test Calibration Position
and Soils & Hydrology Teaching Partner
Extension Program
“Traditional”
Basic Soils
Cotton
Peanut
New “Enhanced Efficiency Fertilizers”
Cotton Team and Peanut Team
County Meetings
Agent Trainings
Invited Lectures
Bulletins, Newsletters, Production Guides
Phone Calls, Emails, Field Days, Troubleshoots
Applied Research Program
Educational Advisor – Georgia Plant Food Educational Society
Teaching
The Increasing Importance of Potassium Fertilization
Glen Harris – UGA Tifton
Fertilizer Prices (cents/lb)
90
80
70
60
Pre=2005
2008
2009
2010
2011
50
40
30
20
10
0
N
P2O5
K2O
Potassium Deficiency
Stemphylium and Potassium Deficiency
Cercospora
Altenaria
Boll Production Compared to DP 555 BG/RR
(1st Position) – Guy Collins/Jared Whittaker
DP 0935
Soil Test K = 46 (low)
Recommended K2O = 135
DP 0949
Soil Test K = 46 (low)
Recommended K2O = 135
DP 555
Soil Test K = 106 (med)
Recommended K2O = 90
Lbs lint/a
K Rate on Cotton – Sunbelt Expo 2009
(STK = 46 Rec= 135 )
DP 0935
1600
1495
1537
1400
1200
1077
42
1000
418
776
800
301
600
400
334
442
200
0
0
45
90
135
180
Foliar K
Calcium Requirement
for Large-Seeded
Runner Peanuts
Glen Harris – UGA, Tifton
Ca++
Ca++
Ca++
Ca++
Current Recommendations
Runner: 500 lb Ca/a – if not, 1000 lb/a gypsum
Large-Seeded Runners: 750 lb Ca/a –
if not 1500 lb/a gypsum ?
Virginias: Automatic – 2000 lb/a gypsum
Calcium (Gypsum) Rate
Ponder Farm (Tifton, GA) – 2009
Pegging Zone Ca – 450 lb/a
Yields (lb/a)
7500
7000
6500
6000
5500
5000
4500
4000
3500
3000
Georgia Green
FL 07
0
500
Tifguard
1000
1500
GA 06G
Effect of Gypsum on Peanut Germination
and Calcium in the Seed
Glen Harris and John Beasley
UGA- Tifton
Calcium (ppm) Content and Seed Germination
Rate Studies (5 Locations) 2009
100
Germination (%)
90
80
70
60
y = -6E-05x2 + 0.0853x + 65.365
R2 = 0.642
50
40
0
100 200 300 400 500 600 700 800
Seed Calcium (ppm)
N=184
“Enhanced Efficiency (EE)” Fertilizers
New Term Coined by The Fertilizer Institute (TFI)
“…products that minimize the potential of nutrient loss to the environment.”
Slow/Controlled Release
Absorbed
Coated
Occluded
Reacted
CoRoN
Stabilized/Additive
Urease Inhibitors
Nitrification Inhibitors
Stabilizers
Humates
Nutrisphere – N (?)
Association of American Plant Food Control Officials (AAPFCO)
Understanding Current Fertilizer Alternatives
Glen Harris
University of Georgia - Tifton
Enhanced Efficiency Fertilizers
For Cotton in the Southeast
Glen Harris
UGA - Tifton Nutrisphere -N
Fertilizer additive that inhibits
degradation of urea by urease
(NBPT)
“Agrotain Plus” (for UAN liquids)
– also includes a nitrification
inhibitor (DCD)
Does not affect microbes
(or other soil organisms) directly
Reduces loss of surface applied
urea-N to volatilization (up to 14
days under drying conditions)
and reduces nitrate leaching
Specialty Fertilizer Products
through Southern States
Polymer “Nutrisphere”
technology
Active Ingredient =
“40 % maleic-itaconic copolymer”
Claims Urease + Nitrification
Inhibition
Mode of action = “shields” N
from Nickel for urease and from
microbes for nitrification
(documented ?)
Materials and Methods
Volatilization
• Closed Chambers
• 6 inch diameter PVC with cap
• Acid Trap analyzed for NH4-N after 7 days
•
•
•
•
Treatments:
Solids: Urea, NSN, Agrotain
Liquids: UAN, NSN, Agrotain Plus
UTC
N Volatilization – Cotton, 3 Location Average
50
48
49
45
40
35
NH4
mg/L 30
25
20
15
15
10
5
0.3
0
Urea
NSN
Agrotain
Control
Questions ?