Matt Ruark, Dept. Soil Sci.
Nav Ghimire, UWEX Green Lake County
Joe Lauer, Dept. Agronomy.
Thierno Diallo, Dept. Agronomy.

NITROGEN FERTILIZERS
Controlled-release
 Polymer-coated
 ESN® (Agrium)
 The polymer coating expands with heat, allowing water in to dissolve the urea.
The soluble N then diffuses out of the porous coating.

NITROGEN FERTILIZER
Delayed release
 Contains a chemical that stops part of the N cycle
 Urease inhibitors
 Inhibits conversion of urea to ammonia
 NBPT
 Agrotain
 Nitrification inhibitors
 Inhibits conversion of ammonium to nitrate
 DCD
 SuperU (contains both NBPT and DCD, impregnated into the urea granule)

QUESTION
 Is there a reliable benefit to using PCU, urease inhibitors, or nitrification inhibitors in
Wisconsin?
 These products come at a premium so there needs to be an economic benefit when using them.
 Greater yield at the same rate of N
 Same yield with lower rate of N

N FERTILIZER TRIALS IN WISCONSIN
 Arlington, WI
 SuperU, ESN, and ammonium nitrate (AN) on corn
 Green Lake, WI
 SuperU, Agrotain, ESN, and urea on no-till corn

2009-2012 TRIALS
 Part of long-term rotation and tillage study at
Arlington, WI
 Rotation
 Corn following corn
 Corn following soybean
 Tillage
 Chisel plow
 No-till
 N applied at planting at a rate of 180 lb/ac

Prev.
Crop
Corn Yield
N Source 2009 2010 2011
Corn AN
ESN
SuperU
224 260
212 261
213 249 bu/ac
193
186
188
Soybean AN
ESN
SuperU
246 268 210 b
240 272 223 a
249 268 201 b
2012
172
157
161
201
196
206
Average
212
204
203
231
233
231

Prev.
Crop
Corn Yield
N Source 2009 2010 2011
Corn AN
ESN
SuperU bu/ac
207 224 ab 183
207 236 a 186
207 216 b 177
Soybean AN
ESN
SuperU
248 264 223 a
241 253 218 a
239 255 208 b
2012
160
167
161
203
182
201
Average
194
199
190
235
224
226

2012 AND 2013 TRIALS
 Location: Green Lake County
 Two fields per farm
 Corn following corn (no-till)
 Corn following soybean (no-till)

APPROACH
 Fertilizers
 Urea
 Agrotain
 SuperU
 ESN
 Rate
 “recommended” vs. 20% reduction
 CC: 170 vs 135
 CS: 150 vs 120
 Controls (unreplicated) of 0 and 200 lb/ac N

ECONOMICS
 Assuming…
 Urea is $550/ton (~$0.60/lb-N)
 ESN is $750/ton (~$0.82/lb-N)
 If N application is 150 lb-N/ac and
 if corn is $4/bu, then need 8 bu/ac gain
 If corn is $5/bu, then need 6-7 bu/ac gain

2012 CORN-CORN
135 VS. 170 LB-N/AC
2012 Corn Yields, Green Lake County
Corn following corn / Sandy Loam
180
160
140
120
100
80
60
40
20
0
U re a
U re a
A gr ot ai n
A gr ot ai n
S up er
U
S up er
U
E
S
N
E
S
N
N on e
U re a(
20
0)

2013 CORN-CORN
135 VS. 170 LB/AC
2013 Corn Yield, Green Lake County
Corn following corn, Sandy Loam
250
200
150
100
50
0
U re a
U re a
A gr ot ai n
A gr ot ai n
S up er
U
S up er
U
E
S
N
E
S
N
N on e
U re a(
20
0)

200
2013 CORN-SOYBEAN
120 VS. 150 LB-N/AC
2013 Corn Yield, Green Lake County
Corn following soybean, Sandy Loam
150
100
50
0
U re a
U re a
A gr ot ai n
A gr ot ai n
S up er
U
S up er
U
E
S
N
E
S
N
N on e
U re a(
20
0)

RESULTS
 These data show that yield gains when applying optimum N rates are not often nor consistently observed.
 The rainfall patterns of the season will create the situation where the product is valuable or not
(i.e. early season intense rains).
 These products were applied at planting. Perhaps greater value if applied 2-3 weeks prior to planting (i.e. more time to protect).
 The products work, but need to be tested on your fields to find the benefit, mostly likely coming from reduced N rates.

WHERE IS THE VALUE?