1. Nutrient Management: Ways to Save Money, From Simple to High Tech
Brian Arnall
Precision Nutrient Management
Plant and Soil Sciences Department
Oklahoma State University 1

2. Rising Prices
Apr-07
Apr-90
Apr-00
Aug-08

4. Lahoma, OK, Winter Wheat
Exp. 502, N rate = (N uptake 100 lb/ac - N uptake 40 lb/ac)/0.5
Optimum N Rate (assuming 40 lbs N/ac preplant) Average Yield Avg. 60 N/ac bu/ac +/ Avg. Loss = $27.5/acre (N at $0.70/lb) 4

5. In field double-triple 12%
Home Run 4%
In field double-triple 12%
Pop fly-out 25%
In-field single 25% In-field out 15%
Pop-up out 10% In-field grounder 9% 5

6. 100 Pre (100 lbs N/ac applied preplant)
SBNRC (YP0*RI =YPN)
100 Pre (100 lbs N/ac applied preplant) 6

7. 2007 Wheat Soil Testing and Education Program
57% get information from Extension
Only 36% always apply recommended amount
Farmer adoption of sensor based technology
Approx 23% adoption
83% (320) not familiar with technology

8. N-Rich Strip A Strip with enough N for the full season.
Double pass with the applicator.
Used as a Reference.
N - Rich
No - P

9. N-Rich Strip
Yes or No

10. N-Rich Strip Sensor Based Nitrogen Rate Calculator
Using Sensor Data and the Nitrogen Fertilizer
Optimization Algorithm, N-Rates are prescribed for that field and its condition.

12. Sensor Base N Rate Calculator IPAQ (load-up files)

13. Ramp Calibration Strip13

14. Ramp Calibration Strip
The Ramp Calibration Strip
16 N rates
0 – 195 lb N ac-1 (can be adjusted for other crops)
Rate Interval 10 ft (adjustable)
Truck, 3pt, ATV mounted

16. 180 N
0 N
180 N

17. Ramp Analysis
Visual based
Sensor Based
SBNRC
Ramp Analyzer 17

18. On-Farm Progress 2004: 300 N Rich Strips
2005: > 1000 N Rich Strips (SBNRC)
2006:
568 Ramps in Farmer Fields
1500 N Rich Strips with one Fertilizer Dealer
Wheeler Brothers
Servicing Approx. 230,000 acres across OK.

19. On-Farm Progress OSU applied 520 ramps
Wheeler Bros. (Danny Peeper) put out 480 ramps, fall of 2007.
Service area >100,000 acres 19

20. VRT
Variable Rate N Application
Resolution
Wheat .4 m2
Corn By-Plant

21. VRT Equipment

22. VRT Equipment

23. Corn
Wheat
Soybean

24. Economic difference of applying lime in 2005 and 2008

25. In the Past OSU recommended banding P on low pH soils when pH was low, on rented land, so that high cost of liming was avoided. Now 1 ton and 30 lbs of P2O5 cost nearly the same amount

26. Questions?