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Yield Monitoring and Mapping

Yield Monitoring

• Most popular precision agricultural operation

• Aids in quantifying spatial and temporal variability in soil and crop properties

http://www.fwi.co.uk/assets/getAsset.aspx?ItemID=5106487

Yield monitors provide a way to quantify yield variations that producers know exist

• Definition of Yield MapM

Yield Monitoring and mapping

• Type of Yield Maps• Cycle of Precision Farming• Methods of Measuring Yields• Yield Monitor Components• Calculating “instantaneous grain yield”

http://www.claas.com/omaha/generator/common/bilder/claas-com/product-world-us/yield-mapping-cover-x564y377.jpg,property=data,lang=en_US-OMAHA.jpg

Yield mapping includes:

• Acquisition

Definition of yield map

A yield map is a spatially referenced, graphical representation ofcrop yield for a defined area.

30 to 185

185 to 195195 to 205205 to 215• Analysis, and

• Summarization of crop yield data bylocation within a field.

Final product is usually a tonal or coloredmap displaying ranges of yield within afield.

Yield bu/ac

1. Inference maps

2. Prediction maps

Types of yield map

3. Interpolation maps, and

4. Aggregation maps.

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1. Inference maps:

Are developed by associating yield estimates with existing mapdelineations without changing the delineations on a base map.

For e.g. associating a yield goal with a soil map unit in a county soilsurvey.

Types of yield map

1A Bojac

29B Wickham

25B Bojac

29B Suffolk

1B AltaVista

1A 140

1B 160

25B 100

29B 175

Yield Goal (bu/ac)

1A Bojac104 lb N/ac

25B Tarboro-Bojac75 lb N/

Low 100

Avg 140

Med 160

Yield Goal (bu/ac)

Variable rate fertilizer prescription map

29B Wickham142 lb N/ac

75 lb N/ac

1B Altavista126 lb N/ac

Med 160

High 175

50 lb N/ac starter band applied on whole field

2. Prediction maps:

Yield component is not measured but predicted from other spatial datausing a prediction function or model.

For e.g. Predicting crop yield as a function of soil/weather properties for aregion or field

Types of yield map

Soil EM 38 readingsSorghum Grain Yield

25.7 to 33.1

23.4 to 25.6

22.4 to 23.4

19.0 to 22.4

3. Interpolation maps:

• Yield measurements are made at specific locations and

• Yield values between data points are estimated using interpolation techniques.

• Measured data are obtained at a much coarser scale than the estimation scale(similar to grid sampling).

Types of yield map

Yield map

Low

Medium

High

Adapted from: http://www.ext.colostate.edu/pubs/crops/00568.html

4. Aggregation maps:

Yield maps derived from measured data in which either the original data or some aggregation of the data are mapped.

Once yield measurements are determined, no estimation, prediction, or interpolation of point yield data is required for mapping because the intensity of data collection is on a very high scale.

Types of yield map

E.g. Site-specific instantaneous (on-the-go) yield monitoring system.

http://valzone.files.wordpress.com/2011/08/img_8201-copy1.jpg

Cycle of precision

Cycle of precision agriculture

http://ces.ca.uky.edu/pendleton/AG_SoilSamples

http://www.farmdata.co.nz/software/Site%20Pro.html

agriculturehttp://www.warmmouse.info/labels/computer%20mouse.html

http://www.agweb.com/seeding-equipment/

http://www.warmmouse.info/labels/computer%20mouse.htmlhttp://geospatial.osu.edu/education/mobileseminar.html

http://www.applylikeapro.com/default.cfm?pid=1.11.4.1&inq_key=41302&action=detail&LibID=1852

http://www.history.com/photos/industrial-inventions/photo9

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Three major yield measuring approaches

1. Collect and weight: The most common and widely used method,weighing crop after being threshed, separated and cleaned.

2. Batch type yield monitors: Grain is weighed in grain tank of combine.It holds large volume or batch of grain harvested from large area

Methods for measuring crop yield

It holds large volume or batch of grain harvested from large areaBatch type-monitor reports total weight/volume of grain over total area.

3. Instantaneous yield monitors: Measure and record yield on-the-go.When combined with positioning system GPS/DGPS, produce site-specific grain yield maps.

http://gaia.pge.utexas.edu/Harmful/Materials/nyt_11_09_05.htm

1. Collect-and-weight method

http://haysvillelibrary.wordpress.com/2010/05/01/

Area harvested

Total Area harvested

Cutting widthInstantaneous Crop yield

Total Crop yield

C i ld/

2. Batch-type method

An in-cab batch-type yield monitor

Crop yield/acre

GPS unit

3. Instantaneous method

8-row header

http://whosyourfarmer.blogspot.com/2010/09/my-family-farm.html

3. Instantaneous method

Instantaneous yield monitor display location crop yield, area, moisture content, etc all in dynamic mode

http://www.kastensinc.com/farminformation/technology/incab.htm

AgLeader InSight display does it all

• planter and application control

• yield monitoring

3. Instantaneous method

yield monitoring

• real-time data logging

• automated steering control, and much more

http://mainstcomputer.com/insight_corn_rh1.JPG

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Grain flow rate (lbs/sec) Combine’s travel speed (ft/sec) Cutting width of header (ft)

Calculating grain yield on-the-go…

Speed

To determine instantaneous crop yield need 3 pieces of information:

Width of header

Example: Calculate the instantaneous grain yield of a combine withan 8-row corn header harvesting at a speed of 10 miles perhour. The corn row width is 30” and the grain flow sensorrecorded a flow rate of 78lbs/sec for the previous second.

Recall: 1mile 5280 ft

Calculating grain yield on-the-go

Recall: 1mile = 5280 ft1 hr = 3600 sec1 acre = 43560 ft

http://farmlandgrab.org/10372

Calculating grain yield on-the-go…

Pixel

20’

14.7

Moving at 10mi/hr = 14.67 ft/sec

Size of the area represented by a yield pixel

One yield pixel/second is collected

PixelHeader width =20 ft

Area harvested = 293 ft2/sec

DC Receiver antenna*

GPS Receiver antenna

Yield Monitor Console**

Grain Flow Sensor**

Grain Moisture Sensor**

Yield monitor components

True ground speed sensor

Header Position Sensor*** DC is Differential

Correction

** components of “yield monitor”

A combine equipped to collect yield data for mapping

Moisture Sensor

Yield Monitor Console

GPS Antenna

Yield monitor components

Ground Speed SensorGrain flow Sensor

Instantaneous Grain yield monitoring system

• Grain Flow Sensor

• Ground Speed Sensor

• Grain Moisture Sensor

• Header Position Switch

• Display Console

I G i Fl S

Basic components

Source Sensor Yield

I. Grain Flow Sensor: Mounted in the path of clean grain flow.

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• Impact Force Sensor

• Plate Displacement Sensor

• Radiometric Sensor/System

Various types of grain flow sensor

• Load Cell System

• Volume Measurement System

(i) Impact Force Sensor:Grain flow is measured by quantifying the amount of force applied

when the grain strikes on a spring-loaded impact plate.

ImpactPlate

Yield

Force is measured by a load cell that converts load into electrical signal.

A very light impact on the plate causes a measurable change in theresistance of the electrical current flow

Change in electrical flow is proportional to amount grain flow

(ii) Plate Displacement Sensor:

Similar to impact force sensor.

Measure displacement of plate and not force.

Grain flow is measured by quantifying the displacement of the plate when

the grain strikes on a spring-loaded impact plate.

DisplacementYi ldPlate Yield Yi ld

Displacement

(ii) Plate Displacement Sensor:

Similar to impact force sensor.

Measure displacement of plate and not force.

Grain flow is measured by quantifying the displacement of the plate when

the grain strikes on a spring-loaded impact plate.

YieldPlate

Yi ldDisplacement

(ii) Plate Displacement Sensor:

Similar to impact force sensor.

Measure displacement of plate and not force.

Grain flow is measured by quantifying the displacement of the plate when

the grain strikes on a spring-loaded impact plate.

YieldPlate Yi ldDisplacement

(ii) Plate Displacement Sensor:

Similar to impact force sensor.

Measure displacement of plate and not force.

Grain flow is measured by quantifying the displacement of the plate when

the grain strikes on a spring-loaded impact plate.

YieldPlate

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(ii) Plate Displacement Sensor:Similar to impact force sensor. Measure displacement of plate and not force.

Mass flow sensor

Loading auger

Clean grain elevator

(ii) Plate Displacement Sensor:Similar to impact force sensor. Measure displacement of plate and not force.

RadiationSource

DetectorSensor Yield

(iii) Radiometric System:Uses a radiation source (Americium 241) Measures the intensity of radiant energy

• Intensity is inversely proportional to grain flow

• It is max. when there is no obstruction (no grain flow)

• It decreases with grain flow

Source directs radiation towards detector

Detector

Clean grain elevator

Radiation

(iii) Radiometric System:

Source

To loadingauger

ow

Simulated Yield Monitor Calibration Curve

0Sensed Force or Displacement

Flo

(iv) Load Cell System:The system actually weighs the grain as it passes through combine’sclean grain auger. Grain flow rate is proportional to the load cellelectrical impulse.

Auger Flighting

Combine Clean Auger Tube

Electronics

Weigh Pad

Transfer Arm

Load Cell

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LightSource Sensor

Yield

(v) Volume Measurement System:

Optical sensor detects the degree to which grain elevator is loaded. Measurement of light and dark period is used to estimate grain flow volume

Must know bulk density (mass/unit volume) to estimate grain yield.

Grain flow (mass) = volume x mass/volume

(v) Volume Measurement System:

Clean grain elevator

Photosensor

Light source

I. Grain Flow Sensor

II. Grain Moisture Sensor

III. Ground Speed Sensor

IV. Header Position Switch

V. Display Console

Various types of Grain Flow Sensor:

Yield monitor components

V ous ypes o G ow Se so :

• Impact Force Sensor

• Plate Displacement Sensor

• Radiometric Sensor/System

• Load Cell System

• Volume Measurement System

Let’s have a look at Grain Moisture sensor

http://www.rawlingsbrokeragecompany.com/page05.html

II. Grain Moisture Sensor:

Grain moisture content is of great practical importance: It affects

• Timing of harvest

• Amount of grain damage during harvest

• Drying cost

• Storage issues (pest damage, etc)

Yield monitor components

Moisture sensor is located in combine’s clean grain conveying system near grain flow sensor.

It is a Capacitance type sensor, works on the principle of measuring di-electric property of a substance (Grain).

Di-electric constant of water = 78 soil ~ 4vacuum ~ 1

Sensor

II. Grain Moisture Sensor:

Yield monitor components

SensorGrain

A capacitance type grain moisture sensor

A capacitance typegrain moisture sensor

II. Grain Moisture Sensor:

Yield monitor components

grain moisture sensor

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Combine speedometer

10 km/h

Ground speed sensor

Yield monitor components

III. Ground Speed Sensor:

An ultrasonic ground speed sensor

III. Ground Speed Sensor:

Yield monitor components

Combine speedometer

10 km/h

Ground speed sensor

An ultrasonic ground speed sensor

In wet slippery conditions

• When header is in raised position area measurement is suspended even when combine is running

• Area measurement is resumed when header is at cutting height

IV. Header switch:

Yield monitor components

http://loupelectronics.com

IV. Header switch:

Yield monitor components

Yield map

GPS point

Yield pixel

V. Display console:

Operator supplied information

• Field name

• Load name or number

• Cutting width

Sensed/Calculated information

• Crop moisture content

V. Display console:

p

• Instantaneous yield

• Average yield

• Area harvested

• Travel speed

• Quality of DGPS signal reception

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Physical Transfer

USB drive

Combine Console

Data transfer in a yield monitoring and mapping system

Laptop/Farm Computer

Yield map and reports

YIELD MONITORING DEVELOPMENTS FOR NON-GRAIN CROPS

• Yield monitoring has been most widely applied to grain harvesting, but is certainly not limited to grains.

• Yield monitors are being, or have been, developed for several non-grain crops as listed in the table below. The list is expected to grow in the near future.

Crop Method Measurement Status Development

Potatoes load cells Commercially available

Tomatoes load cells ”

”Sugarbeets load cells ”

Peanuts load cells ”

Cotton load cells ”

Forage Crops (baled) load cells ”

Forage Crops (chopped) shaft torque sensing exp

Forage Crops (chopped) Load cells expYield Monitor for non-grain crops