Crop Spec, A Collaborative

Partnership A real time integrated plant nutrient monitoring and application system for

Agricultural equipment

Yara Electronic Products ,1995 - Present

CropSpecTM – specifications

Environment IP 67 compliant

Laser safety Class 1 or Class 1M

Physical Dimensions 200 mm x 80 mm x 80 mm

Mounting height 2 - 4 meters

Viewing angle 45°- 55°

Temperature 0 - 60°Celsius

Operational wavebands 735nm and 808 nm +/- 3nm

Supply voltage 10-32 VDC

Supply current 1 A

Sensor Footprint – Oblique View

N status of crops can be measured by analysing reflectance spectral data => non-destructive, non-contacting

IR450 500 550 600 650 700 750 800 850

0

0,1

0,2

0,3

0,4

0,5

0,6

Wavelength, nm

Reflectance

60 kg/ha

120 kg/ha

200 kg/ha

Increase due to increased biomass

Decrease due to increased chlorophyll content

N Supply

N response trail, 1994

Impact of different N supply on the reflectance spectra of winter wheat

IR

400 500 600 700 800 900 1000

W ave le ngth 1 /nm

400

500

600

700

800

900

1000

Wa

vele

ng

th 2

/n

m

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

r2 valuesfor the correlation betweenmeasurements using respective waveband combinationsand cropcharacteristics(e.g. crop biomass, N-uptake)optimum waveband

combination

Waveband to Chlorophyll relationship

The basis for getting meaningful crop information • accurate measurements in various crops and

over a wide range of crop densities• based on know-how and extensive field trial work by Yara• 730-740 nm & 760-810 nm

Source: Reusch, 2005

Crop Spec System Diagram for X20

Implement with Liquid or Granular Application

RS232CANBUS

Topcon X20

Supports all X20 application controllers

CropSpec Parameter Calculation

Define:

R = Simple ratio of NIR reflectance (808nm) to RedEdge (735nm)

R = NIR/ RedEdge

Define:

S1 = 100 * (R – 1) Compare NDVI = (R - 1) / (R + 1)

The CropSpec parameter is defined:

S1CAL = 47 * S1 / S1REF

S1REF is the S1 measured with the reference matching filter.

The 47 factor is used for matching with YARA.

X20 CropSpec User Interface – Maplink

CropSpec (S1CAL)

Histogram

CropSpec OTG Application Models

Negative slope factor also available

OTG Two Point Cal – Strip method

Drive Strip and Apply at Normal Rate

Select min and max CropSpec from cutoff line

Associate two rates => slope factor

Select two point or target rate mode