Three Alternative Three Alternative Nitrogen Management Nitrogen Management Strategies for Cereal Strategies for Cereal

Grain ProductionGrain Production

Brian ArnallBrian ArnallPlant and Soil Sciences DepartmentPlant and Soil Sciences Department

Oklahoma State UniversityOklahoma State University

IntroductionIntroduction

Scrutiny of Nitrogen ApplicationScrutiny of Nitrogen Application Environmental impactEnvironmental impact

Rise in Fuel and Nitrogen costRise in Fuel and Nitrogen cost

Temporal VariabilityTemporal Variability

What Nature ProvidesWhat Nature Provides

Unpredictable VariablesUnpredictable Variables

Response IndexResponse Index

0

1

2

3

4

5

6

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

Year

Gra

in y

ield

, M

g/h

a 0 kg N/ha

112 kg N/ha

1

1.5

2

2.5

3

3.5

4

4.5

19

71

19

73

19

75

19

77

19

79

19

81

19

83

19

85

19

87

19

89

19

91

19

93

19

95

19

97

19

99

20

01

20

03

Year

Re

sp

on

se

Ind

ex Response Index

min: 1.0max: 4.1avg: 1.7

min: 1.0max: 4.1avg: 1.7

N-Rich StripN-Rich Strip

The Nitrogen Rich Strip:The Nitrogen Rich Strip:– What is it?What is it?– When and Where can it be used?When and Where can it be used?

Ease of applicationEase of application

Drive by visibilityDrive by visibility

N-Rich StripN-Rich Strip

Yes or NoYes or No

N-Rich StripN-Rich StripSensor Based Nitrogen Rate CalculatorSensor Based Nitrogen Rate Calculator

Using Sensor Data and the Nitrogen Fertilizer Using Sensor Data and the Nitrogen Fertilizer

Optimization Algorithm, N-Rates are prescribedOptimization Algorithm, N-Rates are prescribed

for that field and its condition. for that field and its condition.

Aug 16, 2002 Aug 28, 2002

NovemberNovember MarchMarch JuneJune

Planting datePlanting datedays from planting to sensing (GDD>0)days from planting to sensing (GDD>0)

YP0YP0

Nitrogen Fertilizer Optimization AlgorithmNitrogen Fertilizer Optimization Algorithm1. Establish preplant N Rich Strip(NRS) 4. Determine Response Index (RI)2. NDVI (biomass) =NDVINRS/NDVIFarmer

3. Predict potential yield 5. Predict potential grain yield need # of days from planting to (YP0) with added N, YPN =(YP0*RI) sensing (INSEY = biomass prod./day) 6. Fertilizer Rec = (grain N uptake INSEY vs. Yld eqn. YPN – grain N uptake YP0/0.7)

1. Establish preplant N Rich Strip(NRS) 4. Determine Response Index (RI)2. NDVI (biomass) =NDVINRS/NDVIFarmer

3. Predict potential yield 5. Predict potential grain yield need # of days from planting to (YP0) with added N, YPN =(YP0*RI) sensing (INSEY = biomass prod./day) 6. Fertilizer Rec = (grain N uptake INSEY vs. Yld eqn. YPN – grain N uptake YP0/0.7)

RIRIYPNYPNMayMay JuneJune AugustAugustCORNCORN

WHEATWHEAT

NDVI (sensing date)NDVI (sensing date)

Ramp Calibration StripRamp Calibration Strip

The Ramp Calibration StripThe Ramp Calibration Strip– 16 N rates 16 N rates

0 – 195 lb N ac0 – 195 lb N ac-1 -1 (can be adjusted for other crops)(can be adjusted for other crops)

Rate Interval 10 ft (adjustable)Rate Interval 10 ft (adjustable)

Truck or Truck or ATV mountedATV mounted

0

20

40

60

80

100

120

140

160

0 20 40 60 80 100

120

140

160

180

200

220

240

260

280

300

Distance, ft

N R

ate

, lb

/ac

Ramp Calibration StripRamp Calibration Strip

Walk it offWalk it off

0 N

195 N

Ramp Calibration StripRamp Calibration Strip

Sensor BasedSensor Based

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0 13 26 39 52 65 78 91 104 117 130 143 156 169 182 195

Fertilizer Rate (lb./acre)

ND

VI

Strip AlternativesStrip Alternatives

VRTVRT

Variable Rate N Variable Rate N ApplicationApplication

ResolutionResolution– WheatWheat .4 m .4 m22

– CornCorn By-Plant By-Plant

VRT EquipmentVRT Equipment

VRT EquipmentVRT Equipment

Questions?Questions?

For More Informationwww.nue.okstate.edu