New Technology and Strategies for Nitrogen Management

Traditional N Recommendations 2 lbs/bushel of wheat 2 lbs/bushel of wheat 1.2 lbs/bushel of corn 1.2 lbs/bushel of corn 50 lbs/ton of bermudagrass 50 lbs/ton of bermudagrass 60 lbs/ton of fescue, small grain pasture 60 lbs/ton of fescue, small grain pasture

Average profit from N = $36/acre/yr Conventional Strategy is Easy and Profitable. Crop N requirement = 2 lb N/bu yield

Temporal and Spatial Variability In season environmental conditions Within field variability

What Scale is Necessary for Precision Ag?

Temporal Variability Historically, it was thought that if N was not applied annually crop production would eventually deplete the soil of its N reserve. Historically, it was thought that if N was not applied annually crop production would eventually deplete the soil of its N reserve. $17/A Benefit from in-season yield estimate

Optimum N Rate (Grain N Uptake Max Yield – Grain N Uptake Check)/0.50 “After the FACT” N Rate required for “MAX Yields” Ranged from 0 to 140 lbs N/ac Long-Term Winter Wheat Experiment Lahoma, OK

GreenSeeker ® Sensor Function Emits Red & InfraRed Wavelengths Outputs NDVI — indicates Biomass and Plant Vigor Day or Night Use No Effect from Clouds

Normalized Difference Vegetative Index - NDVI Calculated from the red and near-infrared bands Calculated from the red and near-infrared bands Measures Biomass Measures Biomass Correlated with: Correlated with: Plant biomass Plant biomass Crop yield Crop yield Plant nitrogen Plant nitrogen Plant chlorophyll Plant chlorophyll Water stress Water stress Plant diseases Plant diseases Insect damage Insect damage

Can Yield Potential (similar to “yield goals”) be Predicted MID-SEASON? Sensor Reading

Winter Wheat, Enid, 2005

Handheld Unit – Temporal Variability In season environmental conditions

Sensor Based Nitrogen Recommendations N Rates Vary from one year to the next, and field to field N Rates Vary from one year to the next, and field to field When you fill up your gas tank, do you put in 20 gallons every time no matter what? When you fill up your gas tank, do you put in 20 gallons every time no matter what? Sensors allow in season decisions for nitrogen rates Sensors allow in season decisions for nitrogen rates

Progress timeline 1991: Developed optical sensors and sprayer control systems to detect bindweed in fallow fields and to spot spray the weed 1993: Sensor used to measure total N uptake in wheat and to variably apply N fertilizer. 1994: Predicted forage biomass and total forage N uptake using NDVI (Feekes 5). 1994: First application of N fertilizer based on sensor readings. N rate was reduced with no decrease in grain yield. 1996: Worlds first optical sensing variable N rate applicator developed at OSU 1997: OSU optical sensor simultaneously measures incident and reflected light at two wavelengths, (670 ±6 nm and 780 ±6 nm) and incident light is cosine corrected enabling the use of calibrated reflectance. 1997: Variable rate technology used to sense and treat every 4 square 1998: Yields increased by treating spatial variability and OSU’s In-Season-Estimated-Yield (INSEY) 1998: INSEY refined to account for temporal variability 1999: Found that adjacent 4 square foot areas will not always have the same yield potential 1999: Entered into discussions with John Mayfield concerning the potential commercialization of a sensor-based N 2000: N fertilizer rate needed to maximize yields varied widely over years and was unpredictable; developed RI 2001: NDVI readings used for plant selection of triticales in Mexico. 2001: NFOA algorithm field tested in 2001, demonstrating that grain yields could be increased at lower N rates when N fertilizers were applied to each 4 square feet (using INSEY and RI) 2002: Ideal growth stage in corn identified for in-season N applications in corn via daily NDVI sampling in Mexico as V : CV from NDVI readings collected in corn and wheat were first used within NFOA’s developed at OSU. 2003: When site CV’s were greater than 18, recovery of maximum yield from mid-season fertilizer N applications was not possible in wheat 2004: Calibration stamp technology jointly developed and extended within the farming community 2004: OSU-NFOA’s (wheat and corn) used in Argentina, and extended in China and India. 2005: USAID Grant allowed GreenSeeker Sensors to be delivered in China, India, Turkey, Mexico, Argentina, Pakistan, Uzbekistan, and Australia. 2006: Delivery of 586 RAMPS and 1500 N Rich Strips (using RCS and SBNRC approaches respectively) in farmer fields across Oklahoma resulted in an estimated service area exceeding 200,000 acres and increased farmer revenue exceeding $2,000,000.

Handheld Unit – Temporal Variability In season environmental conditions Handheld GreenSeeker™ units located in several NE District Extension Offices

Wheat GreenSeeker/N Rich Strip 1 Farm – 43 wheat fields – 1665 Acres 1 Farm – 43 wheat fields – 1665 Acres Traditional Program – 100 pounds N/A Traditional Program – 100 pounds N/A Handheld GreenSeeker ($3600) Saved 149,529 lbs of Urea, $14.59/A, $24,300 Handheld GreenSeeker ($3600) Saved 149,529 lbs of Urea, $14.59/A, $24,300

Regional GreenSeeker Grain Yields

Regional GreenSeeker Profits

2006 NE GreenSeeker/Corn Trials Gross Return ($/A) Treatment Miami South Coffeyville Webbers Falls Ft. Gibson All Site Average Check Farmer Practice N-Rich lbs N – Pre + GreenSeeker N – Pre + GreenSeeker

2006 NE GreenSeeker/Corn Trials Grain Yield (Bu/A) Treatment Miami South Coffeyville Webbers Falls Ft. Gibson All Site Average Check Farmer Practice N-Rich lbs N – Pre + GreenSeeker N – Pre + GreenSeeker

2006 NE GreenSeeker/Corn Trials Total N Applied (lbs N/A) Treatment Miami South Coffeyville Webbers Falls Ft. Gibson All Site Average Check 0 Farmer Practice N-Rich lbs N – Pre + GreenSeeker 112 (37) 93 (17) 110 (35) 132 (57) 112 (37) 0 N – Pre + GreenSeeker

Calibration Stamp Visual Interpretation of “Stamps” provides mid-season fertilizer N recommendation

Nitrogen Stamp N Stamps applied – Nov. 16, 2004

80 N 120 N 40 N N Stamp – Sperry, OK Jan 27, 2005 Wheat planted Sept. 30, 2004 Optical Sensor Alternative N Stamps

40 lbs N 80 lbs N 120 lbs N Ottawa County February 15, 2005 GDD 74 NDVI N Rich.562 NDVI FP.364 Yield Potential 0 N – 42 bushels Yield Potential + N – 73 bushels N recommedation – 75 lbs./A

Distance N Rate NDVI RI = 1.5

N Ramp Calibration Strip

Ramp Calibration Strip Walk it off Walk it off Or use Hand-Held Sensor Or use Hand-Held Sensor Walk it off Walk it off Or use Hand-Held Sensor Or use Hand-Held Sensor 0 N 195 N

RAMP Calibration Strips Ramped calibration strip is superior than yield based N recommendation Ramped calibration strip is superior than yield based N recommendation It can be easily implemented, be used for other fertilizers and amendments It can be easily implemented, be used for other fertilizers and amendments

0 N 325 N 200 N McIntosh County 2007 Visual Estimate from Ramp

0 N 200 N Delaware County 2007 Visual Estimate from Ramp 325 N

We have the capability to fertilize individual plants

Soil Testing Still Needed Every 3 years or less Every 3 years or less Routine test for P,K, pH Routine test for P,K, pH To diagnose production problems To diagnose production problems