Final Exam
May, 2003
SOIL 4213/BAE 4213
Name______
Answer & circle all that apply
STUDENT QUESTIONS
1. Name one way optical sensing can be used to benefit the turfgrass industry?
a. variable rate application of N
b. help researchers rate turf quality
c. better water/irrigation management
d. mapping of turf areas for better management
2. What are sources of information about precision agriculture for farmers?
a. internet
b. books
c. private organizations
d. other farmer
e. all of the above
3. What type of sensors does the CRIS system use?
a. satellite based
b. in field radiometer
c. airplane based camera
d. hand held sensor
4. Variable rate seeding is a new idea that is being developed
True
False
5. What is the number one cause for erroneous soil test results?
Bad soil sampling methods
6. Do larger or smaller farms usually adopt Precision Agriculture Techniques according to the surveys in the presentation on current GPS Adoption in Agriculture?
Larger Farms
7. What year was the Dead Zone the largest in the Gulf of Mexico, and how many square miles did it cover?
2001, 8000 square miles
8. On turfgrass, researchers are using remote sensing technology to detect
a. diseases
b. insects
c. soil compaction
d. nitrogen content
e. drainage patterns
f. overall qualities
PROFESSOR QUESTIONS
1. A component of “precision agriculture” not usually addressed by measures of spatial variability is that of temporal variability, which refers to
a. the extent to which natural process are tempered with by synthetic inputs.
b. the effect of temperature changes on nutrient and water availability.
c. the ratio of surface soil temperature (0-15cm) to subsoil temperature (15-60 cm) as it influences crop development.
d. differences in crop development and nutrient need from one time period to another (year-to-year).
2. A “N-Rich Strip” is a recommended component for field management of temporal variability because it allows
a. within-year calibration of the N soil test for that particular field.
b. evaluation of the yield potential, and extent to which that yield will be supported by non-fertilizer N for that field, that year.
c. evaluation of the effect of soil profile temperatures on crop development over time when N is not limiting.
d. evaluation of rainfall distribution effects over time on crop development.
3. A “Response Index” , when used in relation to N management for a field, provides and estimate of
a. the extent to which N use efficiency may be improved if field spatial variability is measured and treated by N fertilization.
b. the extent to which the crop may respond to an in-season N fertilization if growing conditions continue as they have thus far been experienced by the crop.
c. in-season CV (coefficient of variation).
d. in-season N fertilization losses and N use efficiency (NUE).
4. As sensor-based technology improves the ability to estimate crop yield there should be less need for soil testing to provide estimates of available
a. N.
b. P.
c. K.
d. lime.
5. Hypoxic conditions in the Gulf of Mexico should decrease with time if
a. less fertilizer is used in cereal crop production.
b. crop yields, on average, increase over time.
c. less liquid N fertilizer is used.
d. NUE is increased.
6. The concept of “precision agriculture” refers to agricultural practices that, compared to current approaches, are able to
a. more precisely measure production inputs.
b. Treat and identify areas in the field that need different input levels than other parts of the field.
c. use GPS to identify exactly where a field implement is when it is treating or harvesting any part of the field.
d. more precisely determine the size of a field.
7. Spatial variability that is related to past production management practices in a field is called
a. misuse variability.
b. confounded variability.
c. complex-cell variability.
d. acquired variability.
e. systematic variability
8. For a plant nutrient that is mobile in the soil, like nitrogen, the most important criteria relating to management of fertilizer inputs is
a. knowing or reliably estimating yield goal or yield potential.
b. knowing or reliably estimating available soil nitrogen.
c. the soil texture.
d. soil moisture content at the time of normal fertilization.
9. For a plant nutrient that is immobile in the soil, like phosphorus, the most important criteria relating to management of fertilizer inputs is
a. knowing or reliably estimating yield goal or yield potential.
b. knowing or reliably estimating ‘calibrated’ soil test phosphorus.
c. the soil texture.
d.
e. soil moisture content at the time of normal fertilization.
10. The Coefficient of variation is
a. a Relative measure of the mean
b. Used to evaluate results from different varieties involving the same units of measure (Steel et al)
c. (standard deviation/mean)*100 = (s/x)*100
d. (square root of the variance/mean)*100 = √s2/x, where MSE = s2
e. Used to describe the amount of variation in a population (Cochran)
11. Field Element Size (FES) should theoretically identify (circle all that apply)
a. The resolution where differences in wheat yields are noticed from the air
b. The resolution where spatial variability is inversely related to distance.
c. The smallest resolution where cause and effect relationships can be identified
d. The precise resolution where variances between paired samples of the same size (area) become unrelated and where heterogeneity can be recognized
e. The resolution where misapplication could pose a risk to the environment
f. The treated resolution where net economic return is achieved.
12. For the sufficiency concept, which of the following are true (circle all that apply).
a. Mobility is confounded by immobile nutrients within a time warp.
b. Levels of available nutrients range in a group of soils from insufficient to sufficient for optimum plant growth
c. Quantities of nutrients removed by suitable extractants will be inversely proportional to yield increases from added nutrients
c. immobile nutrients are generally discussed in context with the root system sorption zone
Define:
INSEY = In Season Estimated Yield = NDVI (Feekes 4 to 6)/days from planting to sensing (days with GDD>0) = YP0
GDD =Growing Degree Days = (Tmin + Tmax)/2 – 4.4°C
RINDVI = NDVI from plots receiving adequate but not excessive preplant N, divided by NDVI from plots where no preplant N was applied
RIHARVEST = Maximum observed grain yield (treatment average with N fertilizer) divided by observed yield from plots where no N was applied either preplant or topdress
RISV = Estimate of RI (spatial variability), using the average NDVI value from a random sensor sample (100 m in length) collected in a farmers field + 1 standard deviation, divided by the average NDVI value minus 1 standard deviation.
YP0 = Predicted or potential yield based on growing conditions up to the time of sensing, that can be achieved with no additional (topdress) N fertilization
YPN = Predicted or potential yield that can be achieved with additional (topdress) N fertilization based on the in-season response index (RINDVI) YPN= (YP0)*(RINDVI)
13. Using the following information, compute the response index, projected yield without N fertilizer (YP0), projected yield with N fertilization (YPN), and the fertilizer N rate to be recommended.
(20 points)
YP0 (Mg/ha) = 551(INSEY) - 1.25
YPN = YP0 * RI
% N in the Grain: 2.39
Days, planting to sensing where GDD > 0 98
Expected NUE from topdress fertilizer: 60%
NDVI Farmer Practice: 0.58
NDVI Nitrogen Rich Strip: 0.79
Response Index (RI): ______=0.79/0.58 = 1.36
INSEY: (Farmer Practice) ______=0.58/98 = 0.00591
YP0: (Mg/ha) ______=551(0.00591) – 1.25 = 2.01 Mg/ha
YPN: (Mg/ha) ______=2.01 * 1.36 = 2.73 Mg/ha
Grain N uptake (YP0), kg/ha ______=2.01*1000*0.0239 = 48.0
Grain N upatke (YPN), kg/ha ______=2.73*1000*0.0239 = 65.3
Fertilizer N Rate, kg/ha ______=(65.3 – 48.0)/0.6 = 28.8 kg N/ha
14. The OSU/NTech GreenSeeker sensor pulses broad spectra (incandescent white light) and uses optical filter at 1660 nm and 780 nm to look at red and NIR. (True or False)
15. The OSU/NTech GreenSeeker sensor uses two photodiode detectors; one to measure incident light and one to measure light reflected from the plants and soil surface. (True or False)
16. The OSU/NTech GreenSeeker sensor is an actively lighted optical sensor. (True or False)
17. An optical sensor returns the following data:
Source
/Reading
Red Incident / 200Red Reflected / 2
NIR Incident / 800
NIR Reflected / 24
Calculate the red reflectance value, the NIR reflectance value, and NDVI.
Red Reflectance= 0.01
NIR Reflectance=0.03
NDVI= 0.5
18. The following NDVI measurements were made in farmer’s field on a field N application rate strip and on a non-N-limiting strip. Complete the column for RI and determine the maximum value.
NDVI1X-Field Rate / N Rich /
RI
0.3462 / 0.3884 / 1.120.4411 / 0.4891 / 1.11
0.3370 / 0.5139 / 1.52
0.3227 / 0.5555 / 1.72
0.3792 / 0.5407 / 1.43
0.4546 / 0.6153 / 1.35
0.5163 / 0.7181 / 1.39
0.4199 / 0.6956 / 1.66
0.5303 / 0.5668 / 1.07
0.6333 / 0.5600 / 0.88
Maximum RI = 1.72
19.Match the digital sensor to the multispectral resolution.
a. Duncan Tech / 1) 30 m / B
b. Landsat 5 and 7 / 2) 23 m / C
c. IRS-LISS 3
/ 3) 20 m / D
d. SPOT / 4) 4 m / E
e. IKONIS / 5) 2.8 m / F
f. QuickBird 2 / 6) 1.0 m / a
20. A liquid variable rate applicator is equipped with three valves, 1X, 2X, and 4X. The 1X valve applies fertilizer at 13 lb/ac. What is the maximum application rate?
1x13+2*13+4*13= 91 lb/ac
21. Grain moisture sensors generally use ____ to measure moisture.
a) Capacitance
b) Resistance
c) Mass
d) Voltage
e) Inductance
f) Gamma ray attenuation
22. Which of the following devices are not used on a combine yield monitors?
a) Ground speed sensor
b) Grain Moisture sensor
c) Clean grain elevator speed sensor
d) Grain impact force sensor
e) Header Height sensor
f) None of the above
23. A major problem with existing combine yield monitors is the inability to measure width of cur to the combine. T or F
24. A nanometer is:
g) 1012 m
h) 109 m
i) 106 m
j) 103 m
k) 1 m
l) 10-3 m
m) 10-6 m
n) 10-9 m
o) 10-12 m
25. Give one example why existing granular applicators do not perform well as a variable rate applicator.
a. Distribution patterns of spinner applicators change as applicator rate changes.
b. For pneumatic applicators, the time required for granules to reach outlets at the end of the boom can be greater than 5 seconds longer than to reach outlets at the center of the boom.
c. For applicators equipped with bins holding different materials, the time required to uniformly mix the materials is long.
d. Variability in the density and size of the granules can be great.
26. Why are measurements of a soil or plant property such as P, K, or NDVI for a particular location better than estimating their values using interpolation methods such Kriging and Nearest Neighbor? Interpolation methods estimate the mean or expected value of the property at a specific location by using measurements at locations near the location in question. These methods can make good estimates of the expected value. However the actual measurements have a random component that can be quite large. It is impossible to predict that component, so we cannot predict the actual value.
27. GPS differential correction corrects for:
a. Atmospheric conditions
b. Dark Current in the receiver
c. Time lag between receiving and transmitting data
d. Ephemeris
e. Signal degradation imposed by the Dept. of Defense
28. Sketch and label a semivariogram.
29. Tulsa is located on which UTM zone
g) 12
h) 13
i) 14
j) 15
k) 16
30. The differences between raster and vector systems are:
a. Storage mechanisms
b. visual appearance
c. A and B
d. There are no differences between raster and vector systems.
31. Remote sensing can be divided into four divisions based on altitude of the sensor and they are:
Ground observation: 0-_50 ft_____ ft
Low Altitude Airplane: < _10000______ft
High Altitude Airplane: > _10000____ ft
Satellite: > 150 miles
32. What is NMEA 0183?
NMEA 0183 is the standard for defining the messages used by Global Positioning Systems to communicate latitude, longitude, elevation, time, date and other information. These messages are in ASCII format and can be stored in text files.
33. The semivariance range is arguably the most important spatial analysis statistic. What is it and why is it important for precision farming?
The semivariance range is the statistically determined distance at which measurements of a spatially variable property are no longer related. This is important because you should be able to sense an area less than the range with a single sensor and treat that area at a single rate.
34. GIS software packages store and present data either as vectors and/or as rasters. Briefly define the terms. For what type of data would you prefer raster format and what data would you prefer vector format?
Vectors describe position in space by an angle and a distance measured from a reference point (usually a previously located point). An area is described by a series of vectors circumscribing the area along the boundary.
Rasters are a group of cells in an array whose positions are located by row and column number. The group of cells can describe and area.
Data in a grid such as an image are best described as a raster. If the grid or cell size of different images are the same, cells or pixels of different images can easily by compared.
Geographical features, such as lakes, soil types, and terraces, are best represented by vectors. Files sizes for features described as vectors are generally much smaller and easier to process than raster files.
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SOIL4213 BIOEN 4213