|Collaborative Research with USDA-ARS, University of Nebraska|
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
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).
RI NFOA -nitrogen fertilization optimization
algorithm (based on the response index)
|Corn OFIT Trial, MSEA site, USDA-ARS|
Planted: April 29, 2002
Harvest: September 24, 2002
*one of the check plots was lost due to harvest
Soil N applied at the base of each corn plant, June
Treatment 4 (sidedress application date delayed)
Border rows for treatments 7 and 8 received flat
rates (25 kg/ha)
Evan Brandes (firstname.lastname@example.org),
Central City, NE, April 7, 2005
Paul Gangwish, Shelton, NE April 8, 2005
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.
|David 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.|
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