Precision Agriculture

Chapters 5-8

Read each question carefully and answer fully. Define, circle, list, fill-in, or explain fully. Be sure to write complete, legible sentences.

Section I. (30 pts) True-False. Place a (T) for true items and an (F) for false items.

____1. T of F.Current whole-field management approaches often ignore variability in soil related characteristics.

____2. T of F.Current technology does not permit us to apply pesticide to individual plants while driving across a field.

____3. T of F.Real-time DGPS requires that a vehicle have two receivers (that can be in the same housing.)

____4. T of F.Coast Guard signals cover the U.S. in its entirety.

____5. T of F.Some multi-channel receivers can track 20 satellites simultaneously.

____6. T of F.One can combine GPS and DGPS receivers into one antenna unit.

____7. T of F.Slippage causes travel speed to be underestimated.

____8. T of F.GPS can calculate speed measurements.

____9. T of F.Yield monitoring requires a real-time source of differential correction.

____10. T of F.The PC card stores data in JPEG files.

____11. T of F.About 62% of corn and soybeans acreage is regularly soil tested.

____12. T of F.In no-till fields P levels at the surface are lower that at greater depths.

____13. T of F.The availability of Boron is high at the pH of 8.0.

____14. T of F.NRCS maps are designed for precision farming.

____15. T of F.Both grid point sampling and grid cell sampling are used to generate maps.

____16. T of F.Any time a farmer looks out over a crop we could say that he or she is “remotely sensing.”

____17. T of F.Remote sensing has been used in agriculture since the 1930’s.

____18. T of F.In remote sensing we look at all spectral bands.

____19. T of F.Radar is a passive sensing system.

____20. T of F.Passive sensing systems are more important than active systems in agricultural applications.

____21. T of F.Radar can be used to monitor crop moisture.

____22. T of F.Scans are usually perpendicular to flight paths.

____23. T of F.The larger the pixel size the higher the resolution.

____24. T of F.It has been proposed that 20-meter resolution is necessary for RS data in crop modeling.

____25. T of F.RS data from satellites can currently provide higher resolutions than aircraft.

____26. T of F.Raster data displays have a stair-stepped appearance.

____27. T of F.Vector maps can be created faster than raster maps.

____28. T of F.One problem with a local coordinate system is that it doesn’t correspond directly with USGS or soil survey maps.

____29. T of F.Satellite imagery is usually created with active sensing systems.

____30. T of F.A GIS can link more than one data value to each georeferenced coordinate.

Section II. (30 pts) Multiple Choice/Ranking. Circle the correct answer or rank.

  1. The most important type of position system used in American Agriculture today is
  2. GPS
  3. GLONASS
  4. Land-based
  5. RMS
  6. None of the above
  1. The precision farming operation considered by many to be the logical first step in implementing a precision farming program is…
  2. Building radio towers
  3. Buying all new equipment
  4. Installing irrigation equipment
  5. Crop yield monitoring and mapping
  6. None of the above
  1. The Global Positioning System
  2. Consist of approximately 30 satellites
  3. Was completed in 1985
  4. Is operated by the Department of Defense
  5. A and c
  6. All of the above
  1. GPS satellites
  2. Are equipped with three or four clocks
  3. Contain cesium and rubidium
  4. Forma constellation
  5. A and C
  6. All of the above
  1. Which item is not a component of a grain yield monitor?
  2. Header position switch
  3. Display console
  4. Rotor Shaft sensor
  5. Ground speed sensor
  6. Moisture sensor
  1. Combine yield data is normally stored in/on a ______onboard the combine.
  2. DGPS
  3. Floppy disk drive
  4. PC card
  5. Controller
  6. CD-ROM
  1. In order for sensors to be used properly, you must have
  2. GIS filters
  3. Calibration curves
  4. Sensor curves
  5. Sensor cleaners
  6. None of the above
  1. In order to account for delays in grain movement from the header to the sensor you need
  2. A start of pass delay
  3. A stop button
  4. An operational delay
  5. A ramping button
  6. None of the above
  1. Which factor in not a yield prediction factor?
  2. Soil type differences
  3. Fertility
  4. Soil compaction
  5. Weed control
  6. All are contributing factors
  1. Which of the following factors is not a crop yield monitoring error source?
  2. Abrupt changes in travel speed
  3. Cutting width errors
  4. GPS errors
  5. Field efficiency of turns
  6. Moisture readings
  1. Which of the following are macronutrients?
  2. Sulfur
  3. Nitrogen
  4. Magnesium
  5. Iron
  6. None of the Above
  1. NRCS maps can identify four soil factors
  2. Organic matter, soil texture, drainage and wetlands
  3. Soil texture, drainage, wind directions and net radiometric readings
  4. Organic matter, soil texture, drainage and water holding capacity
  5. Organic matter, CEC, soil texture and wetlands
  6. None of the above
  1. The quality of satellite geometry and error magnitude is
  2. HDOP
  3. VDOP
  4. PDOP
  5. GDOP
  6. None of the above
  1. Which of the following is not a measure of DGPS accuracy?
  2. Circular error probable
  3. Spherical error probable
  4. RMS/2DRMS
  5. SD
  6. All are measures of accuracy
  1. Which require sub-meter accuracy>
  2. Crop yield monitoring
  3. Fishing on the ocean
  4. Machine guidance
  5. A and c
  6. None of the above
  1. During remote sensing we measure
  2. Absorbed energy.
  3. Reflected energy
  4. Emitted energy
  5. b & c
  1. A green plant looks green because
  2. Green wavelengths are reflected
  3. Red and blue are mostly absorbed
  4. a & b
  5. none of the above
  6. Some factors affecting the characteristics of reflected light are
  7. Height of the sun above the horizon
  8. Blue light is scattered more
  9. Ozone layer absorbs most UV
  10. All of the above
  11. None of the above
  1. Rank the following wavelengths from shortest to longest (1 = shortest)

______thermal

______near infrared

______microwave

______HF

______ultraviolet

______visible

______far infrared

  1. Check the following that applies to the State Plane Coordinate System.

______adopted by USDA

______shown on USGS topographic maps

______based on WGS 84

______can have problems at neighboring state boundaries

______often shown on NRCS maps

  1. Check the items as good recommendations for use with GIS software:

______PC card reader

______the fastest speed processor

______large hard drive or hard disk

______15 inch monitor

  1. Supply the appropriate term that fits most closely. Items may be used more than once or not at all.

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  1. Rubber tubing
  2. Peristaltic pump
  3. RS-232
  4. Actuator
  5. Algorithm
  6. Controller
  7. Speed sensor
  8. Flow sensor
  9. PC card
  10. Ultrasonic

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______measures shaft rotational speed

______changes application rate on-the-go

______measures quantity of fluid

______measures true ground speed

______formula that relates input from sensors or maps

______defined by farmer or crop consultant

______port that transfers data to the controller

______standard communications protocol

______responds to signals from controllers

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Section III. (60 pts) Fill-in. Place the appropriate answer in the blanks.

  1. With ______, a planter could position the seed at optimum depth for germination based on available moisture.
  2. Soil testing results are used with crop yield goals and other variables to produce fertilizer application______.
  3. Te Global Positioning System (______) is a satellite-based navigation system operated by the U.S. ______.
  4. The GPS became fully operational in ______. It was originally designed for precise ______navigation.
  5. The service is available ______hours per day and the cost is______.
  6. The space segment consists of ______NAVSTAR satellites in ______orbital planes.
  7. Each satellite orbits the earth once every ______hours. There are ______orbital paths and ______satellites in each path.
  8. This guarantees that at least ______are in view at any time. The arrangement of satellites is called a ______>
  9. Satellite signals can only be received from those that are “______the ______.”
  10. Each satellite is equipped with radio ______and ______.
  11. GPS satellites transmit ______radio signals on separate ______bands.
  12. The signal information that is used to calculate positions is digitally ______.
  13. The L1 signal carries two codes a ______and a ______code.
  14. The L2 signal contains only a ______code and is ______so that only military and authorized receivers can use it.
  15. The correction of position data after it has been collected in the field is called ______.
  16. When the correction data is immediately available to the mobile receiver, this is called ______-______correction.
  17. Grain flow sensors are typically mounted at the top of the ______.
  18. VRA systems can be categorized by the type of product which is applied such as ______, ______, or ______.
  19. To make a planter variable-rate one must make the ______operate at variable speeds.
  20. A variable-depth planter could use a sensor to measure the soil ______content while planting.
  21. Applicators for dry chemicals use ______and ______applicators.
  22. Dry chemical rate application is typically varied by adjusting the ______opening or changing the speed of the ______.
  23. VRA ______applicators have centrally located bins or hoppers and air tubes leading from a metering unit to the point of discharge.
  24. In VR liquid applicators fine adjustments in rates are accomplished by changing system ______.
  25. The three most common coordinate systems are ______, ______, and ______.
  26. A second of longitude varies because lines of longitude ______.
  27. ______is a metric coordinate system commonly used for mapping as scales from 1:500,000 to 1:24,000.
  28. A reference plane of projection is called a ______.
  29. Two common projection datums are ______and ______.
  30. Most GPS receivers can use several datums but ______is common.
  31. Coordinate values in UTM are given in ______with the vertical axis called ______and the horizontal axis called ______.
  32. In remote sensing, ______refers to the size of the smallest object that can be distinguished in an image.
  33. ______are graphs of the frequency of occurrence of different categories of data.
  34. When an image is geometrically corrected we say that it is ______.
  35. Distortion caused by differences in elevation is called.
  36. Geometric correction is accomplished by identifying and using ______.
  37. ______statistics are often used in conjunction with maps to analyze RS data.

Section IV. (80 pts) Listing, and short essay.

  1. List 6 functions of a grain combine. (6 pts)
  2. List 5 basic components of an instantaneous grain yield monitoring system. (5 pts)
  1. List 6 types of information yield monitors typically sense or calculate. (6 pts)
  2. Describe the denitrification. (4 pts)
  3. Explain contour mapping. (3 pts)
  4. List and explain factors that can affect soil-sampling results. (6 pts)
  5. Define precision agriculture. (3 pts)
  6. Sketch the cycle of precision farming. (7 pts)
  1. List four measures of remote sensing performance. (4 pts)
  2. List three drawbacks to using photographic film for RS. (6 pts)
  3. How do we “rectify” a remotely sensed image? (5 pts)
  4. Define interpolation. (5 pts)
  5. List 5 hardware components of a GIS. (5 pts)
  6. List six areas of VRA potential. (6 pts)
  7. What is a FALCON and what functions does it perform? (5 pts)
  8. List several steps to be performed in year one of precision technology adoption. (4 pts)

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