Final Exam May, 2002 SOIL 4213/BAE 4213
Name______
Answer & circle all that apply
STUDENT QUESTIONS
1. What type of costs should be used in the decision process for farmers?
A: Variable Costs.
2. Who is getting "shafted" in agriculture?
A: The small farmers
3. What are three obstacles in applying precision agriculture in Equatorial Guinea?
Equipment (none) Education (none) Money (none) Not much pattern in cropping system No Fertilizer No Herbicides
4. What is the ‘right’ decision that countries should take when they have a problem with water supplies?
1. stop planting and import their food 2. continue planting their crops 3. control the water source 4. adopt new technologies for irrigation 5. adopt precision agricultural production practices
5. Which of the following are concerns in generating sensor based weed detection method
a. Canopy structure similarity of plant species b. Very narrow reflection band for different species c. Confounding effect of environmental stresses d. The 'greenness' of all plants e. All of the above
6. The newly emerging generations of weed detectors are expected to be reliable since:
a. The equipment operates with multi-spectral sensors b. The equipment operates with hyper-spectral sensors c. Technicians will be able to see the weed species with the 'eye-glass mounted' sensor d. East Africa will launch its satellite in early 2003
Page 1 of 7 SOIL4213 BIOEN 4213 7. Which of these soil factors does not affect soil EC readings?
A)Moisture B)Percent Phosphorus C)Cation Exchange Capacity D)Texture E)Temperature
8. What is the anticipated resolution of the Nitrogen Fertilization Optimization Algorithm going to be in Corn (Maize)?
Answer: By Plant!
9. What is the current equation used to calculate NDVI at Oklahoma State University?
(NIR-red)/(NIR+red)
10. List several precision ag services offered by crop consulting companies
Grid sampling Remote sensing Multi-layer map Yield map analysis Insurance claim analysis Aerial Photography Field and management zone mapping Variable rate recommendation
11. Excessive application of N to asparagus results in
a. low quality product b. increase soil pH c. excessive growth of asparagus spears d. all of the the above
12. Provide 2 methods used to achieve a field average or composite result (spatial variability of organic carbon)
Field samples of 15 randomly taken cores Average of results of the 40 plots Composite of samples after processing
13. Why is it necessary to calculate a point of economic efficiency in production agriculture?
To maximize profits
14. List 3 ‘interfering factors’ that are currently problems in sensor-based precision agriculture.
1-Moisture availability (texture, water holding capacity) 2-Nutrient(s) deficiency(ies) and/or toxicity(ies) interactions 3-Crop and Variety within crop
Page 2 of 7 SOIL4213 BIOEN 4213 4-Production system (forage vs. grain) 5-Tillage (background) 6-Weed interference/treatment (increased variability?) 7-Resolution to be treated (field element size) 8-Cost of misapplication (economic vs. environment)
PROFESSOR QUESTIONS
1. The concept of “precision agriculture” refers to agricultural practices that, compared to current approaches, are able to a. more precisely measure production inputs. b. identify and treat parts of 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.
2. The term “spatial variability” used in describing the concept of precision agriculture refers to a. the extent to which specified areas, different from each other, are present within a ‘field’. b. different sized cells that may be used to grid sample and fertilize a field. c. variation, in the vertical dimension, of volumes above the soil surface that are different from each other. d. the accuracy with which small areas (field elements) can be identified within a ‘whole’ field.
3. Spatial variability that is related to past production management practices in a field is called a. inherent variability. b. diffuse variability. c. cell variability. d. acquired variability.
4. 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.
5. 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.
6. The Coefficient of variation is a. a Relative measure of the mean b. (standard deviation/mean)*100 = (s/x)*100 c. (square root of the variance/mean)*100 = √s2/x, where MSE = s2 d. Used to describe the amount of variation in a population (Cochran) e. Used to evaluate results from different experiments involving the same units of measure (Steel et al)
Page 3 of 7 SOIL4213 BIOEN 4213 7. Field Element Size (FES) should theoretically identify (circle all that apply) a. The smallest resolution where cause and effect relationships can be identified b. The precise resolution where variances between paired samples of the same size (area) become unrelated and where heterogeneity can be recognized c. The resolution where misapplication could pose a risk to the environment d. The treated resolution where net economic return is achieved. e. The resolution where differences in wheat yields are noticed from the air
8. For the sufficiency concept, which of the following are true (circle all that apply).
a. Levels of available nutrients range in a group of soils from insufficient to sufficient for optimum plant growth b. Amounts 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
9. If a soil sample is going to be collected which of the following is true (160 acre field) a. collect a random sample from the entire 160 acres b. collect several samples based on position of the landscape c. employ grid sampling (1 to 2 acre grids) d. sample each 1m2 independently e. abandon ship and all hope
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)
10. The OSU/NTech GreenSeeker sensor pulses broad spectra (incandescent white light) and uses optical filter at 660 nm and 780 nm to look at red and NIR. (True or False)
Page 4 of 7 SOIL4213 BIOEN 4213 11. 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)
12. The OSU/NTech GreenSeeker sensor is an actively lighted optical sensor. (True or False)
13. An optical sensor returns the following data:
Source Reading Red Incident 200 Red Reflected 2 NIR Incident 800 NIR Reflected 24 Calculated the red reflectance value, the NIR reflectance value, and NDVI. Red Reflectance= 0.01 NIR Reflectance=0.03 NDVI= 0.5
13. The following NDVI measurements were made in farmer’s field on a field N application rate strip and on a non-N-limiting strip. Calculate the response index, RINDVI using the averaged values of the field rate and the non-N-limiting strips.
NDVI 1X-Field Rate Non-N -Limiting 0.3462 0.3884 0.4411 0.4891 0.3370 0.5139 0.3227 0.5555 0.3792 0.5407 0.4546 0.6153 0.5163 0.7181 0.4199 0.6956 0.5303 0.5668 0.6333 0.5600 Answer: RI=1.3
14.Match multispectral resolution to the satellite. Satellite Resolution Match Landsat 5 and 7 1) 30 m a
IRS-LISS 3 2) 23 m b
SPOT 3) 20 m c
IKONIS 4) 4 m d
QuickBird 2 5) 2.8 m e
Page 5 of 7 SOIL4213 BIOEN 4213 15. The only practical method to change application rates of a liquid fertilizer applicator is to use more than 1 valve and nozzle. Explain how you can obtain 7 application rates plus off with three valves and nozzles. Nozzle the three valves so valve 1 produces a 1X rate, valve 2 produces a 2X rate and valve 3 produces a 4X rate. Rate 1 is obtained by turning on valve 1 – 1X. Rate 2 is obtained by turning on valve 2 – 2X. Rate 3 is obtained by turning on valves 1 and 2 – 1X + 2X = 3X. Rate 4 is obtained by turning on valve 3 – 4X. Rate 5 is obtained by turning on valves 1 and 4 – 1X + 4X = 5X. Rate 6 is obtained by turning on valves 2 and 3 – 2X + 4X = 6X. Rate 7 is obtained by turning on valves 1, 2, and 3 – 1X + 2X + 4X = 7X.
16. Grain moisture sensors generally use ____ to measure moisture. a) Capacitance b) Resistance c) Mass d) Voltage e) Inductance f) Gamma ray attenuation
17. Which of the following devices are not used on a combine yield monitors? g) Ground speed sensor h) Grain Moisture sensor i) Cylinder speed sensor j) Clean grain elevator speed sensor k) Grain impact force sensor l) Header Height sensor
18. A nanometer is: m) 1012 m n) 109 m o) 106 m p) 103 m q) 1 m r) 10-3 m s) 10-6 m t) 10-9 m u) 10-12 m
19. 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.
20. 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
Page 6 of 7 SOIL4213 BIOEN 4213 21. Combine yield monitors provide a precise instantaneous measurement of the grain yield and can be used to determine the grain yields at any location in the field. Is this statement correct? Why? Although we can obtain “instantaneous” yield measurements, these measurements are neither accurate nor precise measures of grain yield at a specific location. There are delays affecting the time the grain reaches the sensor located in the clean grain elevator. These delays include the time the grain takes to move from the various locations in the header to the combine throat, delays caused because some of the grain is not threshed and is returned to the cylinder to be rethreshed, some grain is separated in the cylinder whiled other grain may not be separated until near the end of the straw walkers, grain may pass through the cleaning sieves at different locations, and threshing efficiency changes as the amount of material harvested changes. The result is that the time the grain cut at a specific location in the field reaches the sensor can vary by several seconds. Consequently, the monitor measurements are average or smoothed values and are a good measure of the average yield in an area but not a good measure of yield at a specific location.
Page 7 of 7 SOIL4213 BIOEN 4213