CONTROLLED AND DELAYED RELEASE NITROGEN FERTILIZER TRIALS 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 Chisel Plow systems Prev. Crop N Source 2009 Corn Yield 2010 2011 2012 Average 172 157 161 212 204 203 201 196 206 231 233 231 Corn AN ESN SuperU 224 212 213 bu/ac 260 193 261 186 249 188 Soybean AN ESN SuperU 246 240 249 268 272 268 210 b 223 a 201 b No-till systems Prev. Crop N Source 2009 Corn AN ESN SuperU 207 207 207 Soybean AN ESN SuperU 248 241 239 Corn Yield 2010 2011 2012 Average bu/ac 224 ab 183 236 a 186 216 b 177 160 167 161 194 199 190 203 182 201 235 224 226 264 253 255 223 a 218 a 208 b 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 180 160 120 100 80 60 40 20 a( 20 0 ) e U re N on ES N ES N U Su p er U Su p er n ai ro t Ag ro t ai n a Ag U re a 0 U re Corn Yield (bu/ac) 140 2013 CORN-CORN 135 VS. 170 LB/AC 2013 Corn Yield, Green Lake County Corn following corn, Sandy Loam 250 150 100 50 re a( 20 0) N on e U ES N ES N 0 U re a U re Ag a ro ta i Ag n ro ta in Su pe rU Su pe rU Corn Yield (bu/ac) 200 2013 CORN-SOYBEAN 120 VS. 150 LB-N/AC 2013 Corn Yield, Green Lake County Corn following soybean, Sandy Loam 150 100 50 U re a( 20 0) N on e ES N ES N 0 U re a U re Ag a ro ta i Ag n ro ta in Su pe rU Su pe rU Corn Yield (bu/ac) 200 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? QUESTIONS? COMMENTS? CONCERNS?