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Nitrogen Use Efficiency, Nitrogen Fertilizers, NUE, Nitrogen and the EnvironmentCollaborative Research with USDA-ARS, University of Nebraska

Collaborative Research USDA-ARS, AMES, Iowa
World Nitrogen Use Efficiency for Cereal Production is 33%,
Agronomy Journal 91:357


Yield level and Nitrogen response are Independent (corn and wheat)  J. Prec. Agriculture 12:508-518

2005 Evan Brandes Cooperation
Corn Trial conducted jointly with Dennis Francis and Jim Schepers, USDA-ARS, University of Nebraska, Lincoln, NE.  Corn trial located near Shelton, NE. Harvested in October, 2003

Summary 2003:  Using the maximum yield Nitrogen Fertilization Optimization Algorithm (NFOA), grain yields were increased by 4 bu/ac when compared to the 80-85 N split (treatment 10 versus 4).  For treatment 10 and treatment 4, 80 lb of N /ac was applied at a fixed rate preplant.  When topdress N was applied on June 17, 2003, fixed rates were applied in treatments 2, 3, and 4.  Treatments 7-11 received topdress N applied using the variable N rate applicator (illustrated below) capable of sensing and treating each corn plant individually.  Grain yields were increased by 4 bu/ac for treatment 10 when compared to treatment 4, using 42 less lb N/ac.  As a result, the nitrogen use efficiencies of this treatment were 10% better than the split N treatment (treatment 10 vs 4, 40% NUE, and 30% NUE, respectively).
 
Corn OFIT Trial, MSEA site, USDA-ARS   Planted:  
2003 Harvest:
Treatment Preplant Rate Sidedress Rate N Rate Total N Rate Grain Yield NUE
    10 to 12 leaf stage Pre+topdress      
  lb N/ac lb N/ac lb N/ac lb N/ac bu/ac %
1 0 0 0 0 118
2 0 89 89 89 165 37
3 0 161 161 161 170 23
4 80 85 165 165 193 30
5 80 0 80 80 180 53
6 160 0 160 160 181 27
7 0 RI-NFOA 0+37 37 141 41
8 80 RI-NFOA 60 % NUE 80+25 105 177 41
9 0 MY-NFOA 0+64 69 165 42
10 80 MY-NFOA 80+43 123 197 40
11 80 RI-NFOA 40% NUE 80+61 141 175 28
SED 11 13
 
Replications 4 NDVI N Rich 0.513 RI = 1.2
Soil N applied at the base of each corn plant NDVI Check 0.448

RI NFOA -nitrogen fertilization optimization algorithm (based on the response index)
MY MFOA - nitrogen fertilization optimization algorith (based on maximum yield)
Damaged Plots (Application Error, removed from analysis & entered as missing data) 101, 102, 103, 104, 105, 308

 
Corn OFIT Trial, MSEA site, USDA-ARS
Planted: April 29, 2002
Harvest: September 24, 2002
Treatment Preplant Rate Sidedress Rate Total N Rate Grain Yield NUE Std. Dev.
  8 to 12 leaf stage
  lb N/ac lb N/ac lb N/ac bu/ac bu/ac
1 0 0 0 107.9 0 15
2 0 70 70 118.2 10.3 21
3 0 140 140 115.1 3.6 21
4 70 70 140 128.3 10.2 15
5 70 0 70 124.1 16.2 14
6 140 0 140 123.8 7.95 10
7 0 RI NFOA (23) 23 105.9 0 22
8 70 RI NFOA (23) 93 130.6 17 15
9 0 flat RI NFOA (22) 22 94.3 0 33
10 70 flat RI NFOA (22) 92 129.1 16 6

*one of the check plots was lost due to harvest error
NFOA - nitrogen fertilization optimization algorithm (N applied to each plant)
flat NFOA - average N rate determined from treatments 7 and 8, applied uniformly to treatments 9 and 10.
Treatment 4 topdress applied 2 weeks later.

Replications  4
Days from planting to sensing

Soil N applied at the base of each corn plant, June 11, 2002
4/29/2002

Treatment 4 (sidedress application date delayed)
6/11/2002

Border rows for treatments 7 and 8 received flat rates (25 kg/ha)
Center 2 rows of treatments 7 and 8 were fertilized by-2-plants

 
Evan Brandes (bran@cconline.net), Central City, NE, April 7, 2005
308 940-0202


Paul Gangwish, Shelton, NE April 8, 2005
Dr. James SchepersDr. Jim Schepers inspects one of the many variable N rate trials conducted near Shelton Nebraska at the USDA-ARS MSEA site (June 22, 2004).  Dr. Schepers was the first scientist to establish Nitrogen Reference Strips for calibrating in-season fertilizer applications.

 

 

By-plant determination of NDVI using the GreenSeeker sensor near Shelton, NEDavid Smith (NTech Industries) and Kent Martin prepare to collect by-plant sensor readings near Shelton, NE using a GreenSeeker sensor and a shaft encoding device that writes distance to the same file where NDVI readings are collected.  This allows for accurate determination of average NDVI on a by-plant basis.
Corn OFIT Trial, MSEA site, USDA-ARS      
Planting date:
Harvest date:
Preplant N Fertilization:
Topdress N fertilization: June 11, 2002
Treatment Preplant Rate Sidedress Rate Total N Rate Grain Yield Std. Dev.
    8 to 12 leaf stage      
  lb N/ac lb N/ac lb N/ac bu/ac bu/ac
1 0 0 0 107.9* 15
2 0 70 70 118.2 21
3 0 140 140 115.1 21
4 70 70 140 128.3 15
5 70 0 70 124.1 14
6 140 0 140 123.8 10
7 0 NFOA (23) 23 105.9 22
8 70 NFOA (23) 93 130.6 15
9 0 flat NFOA (22) 22 94.3 33
10 70 flat NFOA (22) 92 129.1 6
  SED = 12.4
*one of the check plots was lost due to harvest error, and this mean is likely overestimated (based on the other 3 values)

Summary 2002:
1. Applied N increased yields by more than 22 bushels/acre
2. OSU-NU NFOA (trt 8) produced equivalent yields using 47 less lbs N/ac Preplant 70 + Fixed 70 (trt 4)
3. When no N was applied Preplant, by-plant N rates increased yields by 11.6 bu/ac (7 versus 9) compared to flat N rates
4. When 70 lb N was applied preplant, by-plant N rates had equal yields (8 vs 10) compared to flat N rates
5. Nitrogen applied mid-season to plots receiving no preplant N could did not result in equivalent yields when compared to all N applied preplant and/or split applied (early season N stress should be avoided).

 

Dr. Jagadeesh Mosali applies fixed N rates in a collaborative corn trial with Dr. Dennis Francis and Dr. Jim Schepers (MSEA site, near Shelton, NE), June 11, 2002

 

Comprehensive information on Nitrogen Use Efficiency for cereal crop production
N Tech Industries