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

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

Lahoma, OK, Winter Wheat Optimum N Rate (assuming 40 lbs N/ac preplant) Average Yield Avg. 60 N/ac 42.8 bu/ac +/ Avg. Loss = $27.5/acre (N at $0.70/lb) Exp. 502, N rate = (N uptake 100 lb/ac - N uptake 40 lb/ac)/0.5

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

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

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

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

N-Rich Strip Yes or No

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.

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

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

0 N 180 N

Ramp Analysis Visual based Sensor Based SBNRC Ramp Analyzer

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.

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

VRT Variable Rate N Application Resolution –Wheat.4 m 2 –Corn By-Plant

VRT Equipment

Economic difference of applying lime in 2005 and 2008 SOYBEAN

Questions? CR-2255

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