Nitrogen Use Efficiency, Nitrogen Fertilizers, NUE, Nitrogen and the EnvironmentCorn Research
1. Mexico Sensor Results 2002-2003
2. Foliar Application of UAN in Corn
3. Corn Research, Ohio State University
Optimum Corn Temperatures

Kevin Raun, Corn-Soybeans-Wheat Rotation


 Wheat rust, Nebraska IMG_1064.MOV

 

Figure 1. Relationship between corn by-plant dry yields and NDVI sensor measurements multiplied times plant height at 6 locations, 2003.

Can By-Plant yield levels be predicted at early stages of growth?  Figures 1 and 2 suggest that this can indeed take place in corn.

Figure 2.  Relationship between wet yield and by-plant NDVI sensor readings taken at V7, V8, and V10 stages in corn.

By row differences in corn color as a function of N deficiency, Mead, Nebraska


Paul Hodgen (B.S., and M.S. Oklahoma State University), and current Ph.D. student at the University of Nebraska operates one of the variable N rate applicators developed for corn near Shelton, NE (June 17, 2003).

Corn, V5, Efaw OK, 2003


 


Do corn roots overlap when plants are more than 7 inches apart?  When corn plants were excavated from a corn field to a depth of 2 feet, few rooting cylinders overlapped, unless plants were less than 7 inches apart.  Over 70% of the root mass was found to exist within a 6 inch diameter of the stalk, further supporting by-plant variable N application in corn.


After excavation and complete root washing, corn plants were placed in the exact same location as from the slide above.  Root systems from these plants were then thoroughly evaluated.  Unless the plants were within 6 inches of each other, the 70% by-plant root mass (exists within a 6 inch radius of the stalk) did not overlap with bordering plants.  Thus treatment of each plant or every 2 plants within 6 inches makes a lot of sense in corn since N can be accurately placed within the 70% root mass. 

2004 Variable N Rate Applicator for Corn, June 1, 2004.  Brian Arnall operates this reconfigured unit that senses and applies variable N rates, by plant.  Visible in the pictures are the sensors that travel 3 feet above the row, and the drop down nozzle systems (3 per cluster).

Perkins, OK Corn OFIT trials managed by Kyle Freeman & Brenda Tubana.  This trial sensed on June 4, 2004, had a response index of 1.34.

Brenda Tubana, Roger Teal, and Jason Taylor inspect the CORN OFIT trial at the Efaw Experiment Station. 

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:  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


Corn trials at the EFAW experiment station, June 2004.

Comprehensive information on Nitrogen Use Efficiency for cereal crop production