2004 Crop Nitrogen Algorithm Workshop

Gyles Randall:
1.Topdress N needs to take place before V12
2. Split N better under high rainfall & sandy soils
3. Identified sites where preplant N was better
Jerry Hatfield:
1. Inconclusive data on the ability of the Sensors to detect differences in hybrids

Fred Below
1. Problems associated with yield maps
2. Range of Yield Levels (Yield Map) were 120 to 190 (1.58X)
3. Differences in Corn Hybrid NUE and Response to applied N?
4. Consistent boost in grain protein from increasing N applied
5. Number of kernels highly correlated with N applied (kernel # established between v8 and v12)
6. Challenge:  Sink-driven yield response to applied N

Robert Mullen
1. RI-Harvest can be predicted with RI-NDVI
2. Red NDVI capable of detecting N rate differences at v4 and v6
3. Need for better RI-NDVI vs. RI-Harvest relationship in corn

John Lamb
1. Improved N Management in sugar beets has large economic impact
2. Excess N application in soybean-corn-beet rotation
3. Early growth in beets important, thus the need for high N at planting
4. Application of sensors for disease recognition
5. Sugar beet top N credit (late fall NO3-N test not successful)

Nicolas Tremblay
1. Integrating soil productivity potential
2. DUALEX Sensor
3. Decreased N at planting combined with the use of N Rich Strips
4. Appropriate Rate for N Rich Strips?

Newell Kitchen
1. Convenience of Precision Ag Practices (adoption)
2. Knowing what the yield is, is not helpful for predicting N rate (Resolution?)
3. Need for by-plant resolution?
4. Need for more complicated N Rich Strip

Ken Sudduth
1. Sensor evaluation
2. Development of liquid based, high clearance equipment

Dennis Francis
1. Problems associated with different sensors
2. Problems in recognizing differences in the field and selecting the right N rate
3. NIR differences within rows more pronounced
4. Reported on variability within sensors
5. Seed placement (leaf orientation) may be required for precision planting
6. Planting depth influences stalk diameter
7. Leaf orientation (Wilhelm) influence on yield
8. Re-evaluation of vegetation indices

John Shanahan
1. Importance of In-Season N Approach
2. Application Window:  v8 - vt
3. Variable N Response Across the Landscape

Dan Walters
1. Model for Predicting Corn Grain Yield

Fernando Solari
1. Differences in time of day for active sensors
2. Off the row ---- NDVI underestimated, more important at early stages of growth
3. Leaf wetness, was not an issue

Paul Hodgen
1. Need for N Management Zones
2. Sensor angle:  Nadir better than at 45 degrees
3. Nadir probably better for plant height

Tom Bowen
1. Good Correlation of RNDVI and N applied

Kevin Bronson
1. Good Correlation of RNDVI and N applied

Tom Clarke
1. GreenSeeker vs. Exotech
2. Found good separation of N rates using active sensors

Ivan Ortiz-Monasterio
1. Foliar UAN in Durum & Breadwheat resulted in 85+% of maximum yield
2. NRich strip successful in predicting the need for N

Kyle Holland
1. Differences between sensors


Comprehensive information on Nitrogen Use Efficiency for cereal crop production