Late Nitrogen Late Nitrogen Frenzy Frenzy Ben Rosser, OMAFRA Dave Hooker, UG-Ridgetown Adapted from: Greg Stewart (Maizex) and Jason Van Mannen (Veritas) #SWAC16
The 4-Rs of nutrient mgmt.
N rate determination? Ontario Corn Nitrogen Calculator PSNT Accuracy?
N rate depends on year! Guelph loam Near Elora Source: Deen et al. 2015 Better Soils and Crops
N rate depends on year! Guelph loam Near Elora 2012: 120 lbs Source: Deen et al. 2015 Better Soils and Crops
N rate depends on year! Guelph loam Near Elora 2012: 120 lbs 2013: 220 lbs Source: Deen et al. 2015 Better Soils and Crops
N rate depends on year! Guelph loam Near Elora 2012: 120 lbs 2013: 220 lbs Source: Deen et al. 2015 Better Soils and Crops
Bender et al. (2013) Agron. J. 105:161-170
Sidedress 10% Bender et al. (2013) Agron. J. 105:161-170
Tassel Rapid Uptake Sidedress 70% 10% Bender et al. (2013) Agron. J. 105:161-170
Tassel 70% Sidedress 10% Bender et al. (2013) Agron. J. 105:161-170
Tassel 70% Sidedress N Remobilization To Grain 10% Bender et al. (2013) Agron. J. 105:161-170
Bender et al. (2013) Agron. J. 105:161-170 Credit: Pioneer Crop Insight March 2014
N Loss in Corn Fields 1) Denitrification 2) Leaching
Denitrification NO 3 -> NO 2 -> NO -> N 2 O -> N 2 Plant Available Gaseous Loss ------------------------> Credit: Iowa State
Denitrification NO 3 -> NO 2 -> NO -> N 2 O -> N 2 Plant Available Gaseous Loss ------------------------> Soil Temperature (C degrees) Potential nitrate loss in saturated soil (% per day) < 12 1-2% 12-18 2-3% > 18 4-5% Source: Hoeft (2002; Univ. IL)
Leaching NO 3 - NO 3 - NO 3 - NO 3 - NO 3 - NO 3 - Adapted from University of Nebraska - Lincoln
Sidedress N Credits Sidedress N Recs From Ontario N database Soil Type % of Preplant Rec <50% Sand (clay, loam, silt): 80% 50-80% Sand (sandy loam): 90% >80% Sand (sand, loamy sand): 100%
Soil Temperature (C degrees) Potential nitrate loss in saturated soil (% per day) < 12 1-2% 12-18 2-3% > 18 4-5%
Soil Temperature (C degrees) Potential nitrate loss in saturated soil (% per day) < 12 1-2% 12-18 2-3% > 18 4-5% > 75% of N Available for Loss 7-8 Weeks?
Equipment options
High Yield Contest Winners Several (Francis Childs, David Hula, Randy Dowdy) have spoken across Ontario All have promoted the concept of feeding the crop late (VT) to maximize yields.
Key Question. Does a late season N applic. (V10 VT) provide an economic advantage over earlier application strategies? If total N applied should be close to MERN in a typical year If total N applied is similar (+/-) across all comparisons
Yield (bu/ac) Ontario Nitrogen Timing Preplant vs. V6 250-2014 and 2015 - Same amount of total N, 50-150lb at different times Preplant V6 200 150 100 50 0 Norfolk Lambton Huron Bornholm Elora Huron
Yield (bu/ac) Ontario Nitrogen Timing Preplant vs. V6 vs. V10-12 250-2014 and 2015 - Same amount of total N, 50-150lb at different times Preplant V6 V10-V12 200 150 100 50 0 Norfolk Lambton Huron Bornholm Elora Huron
Yield (bu/ac) Ottawa Valley N Timing 300-9 Locations in 2015 - Grower s standard rate as SD (V6) or split (70% V6 and 30% V10-V12) V6 Split (V6 & V10-12) 250 200 150 100 50 0 1 2 3 4 5 6 7 8 9 Location
Yield (bu/ac) Bruce Soil and Crop All Preplant N vs. Split N - Average of 4 locations in 2015 200 150 167 170 163 168 169 100 50 0 100% Pre 70% Pre 30% V10-12 100% Pre 70% Pre 30% V10-12 50% Pre 50% V10-12 120 lb N/ac 180 lb N/ac
Maizex Agronomy Data, 2015 Site Base N Late N Yield Campbellford 150 203 Plus 50 - June 23 202 Plus 50 - July 16 210 Granton 150 235 Plus 50 - July 22 236 Erin 180 194 Plus 50 - June 18 196 Plus 50 - July15 192 Millbank 160 164 Plus 50 - July 5 193 Langton 160 187 Plus 50 - June 19 211 Plus 50 - July 11 207 Kingston 135 222 Plus 50 - July 16 230 Plus 100 - July 16 249 Source: G. Stewart, Maizex Seeds
Becks Hybrids Data High Clearance Sidedressing
Beck s Hybrids 4-year average comparing traditional sidedress to V10 high clearance sidedress. 3 bu/acre response to V10 app
Yield loss? 31
Summary of little independent data (at equivalent total N) Late N application does NOT consistently increase yields (or profitability) Any late N advantage seems to disappear after VT
Recap: Late N Advantages Timely for crop uptake during grainfill Planting timeliness Reduce the size of the N pool and reduce the risk for loss* Rate adjustment given conditions*
Reducing the Nitrate Pool Leaching Lighter soil Early N moving down with moisture Denitrification Heavy soil Gaseous losses of N in saturated conditions
Soil N Testing (Late) What do Soil N Tests Mean once Crop N Uptake is Significant? i.e. V10 + Perhaps Nothing!
NO3-N (ppm) 70 60 50 Nitrate Monitoring in Oxford County Site, 2009 40 30 20 10 0 25-Apr 9-May 23-May 6-Jun 20-Jun 4-Jul 18-Jul 1-Aug 15-Aug 29-Aug 12-Sep 26-Sep 10-Oct 24-Oct 7-Nov Year 2009 ESN138 Urea138 Control5
N Rate Adjustment Millbank, ON example 2015 Factor Situation Is yield potential high? High with 37,000 PPA.
N Rate Adjustment Millbank, ON example 2015 Factor Situation Is yield potential high? High with 37,000 PPA. May / June rain excessive? High - 9 in June
N Rate Adjustment Millbank, ON example 2015 Factor Situation Is yield potential high? High with 37,000 PPA. May / June rain excessive? Soil nitrate values? High - 9 in June Relatively low but what do they mean at late stages?
N Rate Adjustment Millbank, ON example 2015 Factor Situation Is yield potential high? High with 37,000 PPA. May / June rain excessive? Soil nitrate values? Plant colour / NDVI? High - 9 in June Relatively low but what do they mean at late stages? Fading between tiles
What to do after 9 inches of rain in June? G. Stewart, Maizex Seeds
What to do after 9 inches of rain in June? +18 +41 G. Stewart, Maizex Seeds
Other late N considerations Placement? Agrotain? Precision ag approaches? Hybrid effects?
Consider Placement.
Consider Agrotain Cost and loss considerations N Rate (lbs N/ac) Product 50 65 Urea $38 $47 Urea + Agrotain $42 $52 UAN $44 $53 UAN + Agrotain $48 $58 ESN $51 $64 J. Van Maanen, Veritas
Consider Agrotain Cost and loss considerations N Rate (lbs N/ac) Product 50 65 Urea $38 $47 Urea + Agrotain $42 $52 UAN $44 $53 UAN + Agrotain $48 $58 ESN $51 $64 J. Van Maanen, Veritas
Agrotain? Yes to some of these Qs? Is the soil damp at the surface? Is there significant residue on the soil surface? Is the weather forecast dry? Is the canopy fully developed?
Consider precision ag approaches Do sensors (i.e. GreenSeeker) give you more meaningful information later in the season? -- YES! What does it mean though
Source: Veritas Consider precision ag approaches Greater variation in NDVI at V12 compared to V3 Much greater plant uptake at V12 V3 V12
Future: hybrid-specific responses NDVI Visual Source: Dr. Tony Vyn, 2015
Late N Conclusions!! 1. Does NOT consistently increase yields or $ 2. Economic benefits possible with in-season mgmt. 3. Possible environmental risk lowered with multiple apps 4. Agrotain: Urea likely benefit more than 28%
Conclusions 5. Soil N tests later than PSNT likely not useful 6. N uptake likely needed by VT 7. Sensor opportunities 8. Hybrid-specific N responses may be an opportunity 9. Much more Ontario research is required
QUESTIONS? Ben Rosser ben.rosser@ontario.ca Dave Hooker dhooker@uoguelph.ca @cropdoc2