AGRONOMY 114 Final Exam Page 1

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DIRECTIONS:

MARK THE ONE BEST ANSWER ON YOUR ANSWER SHEET.

1. To minimize corn yield loss and damage from European Corn Borer,

one should fertilize with

a) more than normal amounts of N fertilizer

b) more than normal amounts of rhizobium fertilizer

c) normal amounts of N, P, and K fertilizer

d) more than normal amounts of N and less than normal

amounts of K fertilizer

e) more than normal amounts of P and less than normal

amounts of K fertilizer

2. A plant has reached physiological maturity when its seed has

a) maximum LAI

b) maximum green weight

c) maximum seed set

d) maximum water content

e) maximum dry weight

3. Which crop would require more shallow planting depth for good

emergence

a) peanuts

b) soybeans

c) wheat

d) grain sorghum

e) alsike clover

4. In order for seed of most species to germinate which of the

following is required

a) a short period of darkness

b) a period of cold temperature

c) CO2

d) nitrogen

e) oxygen

5. Descending air in the troposphere generally

a) increases in water vapor

b) decreases in air pressure

c) increases in temperature

d) absorbs UV light

e) increases growing degree days

6. The three parts of the disease triangle that are necessary for

severe disease to occur are pathogen, environment and

a) bacteria

b) virus

c) dissemention

d) virulence

e) host

AGRONOMY 114 Final Exam A Page 2

7. If you were a plant breeder selecting for greater crop digestibility

to ruminants, what agronomic trait might be reduced?

a) leaf-to-stem ratio

b) leaf photosynthetic rate

c) transpiration ratio

d) lodging resistance

e) rooting depth

8. Soil compaction

a) is reduced by conventional tillage

b) usually results in increased yield

c) is reduced by freezing and thawing

d) can be avoided by working the soil while it is wet

e) provides a good environment for root growth

9. Some berry crops in California are grown in beds covered with

plastic using drip irrigation. Plastic is used to

a) reduce humidity

b) reduce evaporation

c) reduce air temperature

d) reduce wind speed

e) reduce transpiration

10. Suppose a single female nematode can lay 500 eggs, of which

approximately 50% will grow into females, and that there can be

five generations produced in one growing season in a particular

region. Assuming no deaths occurred, what would be the total

population of nematodes at the end of the growing season?

a) (500) to the 5th power

b) (500) to the 0.5 power

c) (250) to the 5th power

d) (500)x 5

e) (250)x 5

11. To what percent moisture would you dry grain sorghum for

long-term storage?

a) 6%

b) 14%

c) 25%

d) 40%

e) 70%

12. The economic threshold for an insect in soybeans would be

a) less if soybeans were not adequately fertilized

b) less if soybeans were irrigated when drought stressed

c) more if soybeans were close to the reproductive period

d) more if soybeans were grown in cool, wet conditions

e) more if soybean nodules were not adequately formed

AGRONOMY 114 Final Exam A Page 3

13. A pea plant is Tt genetically for its height genes (T = tall

is dominant over t = short). If this plant is pollinated by

an identical plant what will be the ratio of tall to short

plants in resulting offspring?

a) 4:1

b) 3:1

c) 1:1

d) 1:3

e) 2:1

14. The better agricultural term for "trash" in the field is

a) crop residues

b) biological yield

c) garbage

d) refuse

e) John Deere equipment

15. Which reason best accounts for Iowa having some of the best

soils in the world?

a) trees

b) native prairie grasses

c) lakes

d) annual weather patterns

e) earth quakes

16. Which change would likely increase the irrigation frequency

needed for producing grain

a) switching from a field of sandy loam soil to a field of

silt loam soil

b) switching to a crop with similar rooting patterns but with

a higher transpiration ratio

c) switching to a deeper rooted crop

d) switching to a crop with lower water use per day

e) moving the production area to an area of higher relative

humidity

17. A primary reason for the use of a companion crop with a

mixture of a forage grass and legume is

a) to provide fixed nitrogen for the mixture

b) to act as a trap crop for forage insects

c) to cause fast growth and elongation of the forages

d) to help control weeds until the forages are established

e) to shade the soil and conserve moisture

18. The result of selfing in crops is to

a) move the traits toward homozygosity

b) increase the number of heterogeneous populations

c) reduce the amount of inbreeding

d) increase the amount of segregation among the F6 traits

e) increase the amount of hybrid vigor in offspring

AGRONOMY 114 Final Exam A Page 4

19. An example of an oil crop which is also a pulse crop is

a) sunflower

b) peanuts

c) maize

d) safflower

e) navy beans

20. Which best describes photosynthesis?

a) sunlight evaporates water from the surface of green leaves

and causes roots to take up water with dissolved nutrients

b) atmospheric nitrogen is fixed in root nodules to allow

vegetative plant growth to take place

c) atmospheric carbon is fixed in organic form by combination

with water by means of solar energy

d) energy-rich carbohydrates are broken down to provide fuel

for plant growth

e) the process that determines the concentration of

phytochrome in leaf cells and is associated with the

initiation of flowering

21. Mr. Farmer is planning to buy some seed oats for next spring.

Variety A costs $3.00 per bushel, has a germination percent

of 85 and a purity of 95 percent and the desired population

can be obtained by planting viable seed at a rate of 128

pounds per acre (32 lbs/bu.). To what seeding rate will he

adjust his grain drill?

a) 39.6 lbs/A

b) 142.2 lbs/A

c) 158.5 lbs/A

d) 37.2 lbs/A

e) 134.7 lbs/A

22. Planting narrow-row soybeans with a mechanical row crop planter

in order to establish canopy closure sooner in the growing

season is an example of what type of weed control?

a) cultural

b) mechanical

c) biological

d) chemical

e) not related to weed control

23. Low pH

a) indicates an acid soil

b) indicates an alkaline soil

c) soils are common under arid conditions

d) soils are infertile

e) indicates a low hydrogen ion concentration

AGRONOMY 114 Final Exam A Page 5

24. Fine German brewers' malt is made of barley caryopses that have

grown after one day of germination. The purpose of the malt is

to supply the yeast organisms with the energy necessary to

produce ethanol (alcohol), a process known as fermentation.

What is the original source of the energy for the brewing industry?

a) The black layer

b) The apical meristem

c) The aleurone

d) The endosperm

e) The phytochrome.

25. Which soil textural class would allow earlier planting dates

and lower amounts of fertilizer application for non irrigated

crops?

a) loam

b) silty clay loam

c) silt

d) sandy loam

e) silty clay

26. If you are facing south and the wind is coming from the

north, striking you in the back, a low pressure cell is

a) north of you

b) south of you

c) east of you

d) west of you

e) directly over you

27. Insect populations would develop resistance to a chemical

a) faster than weeds because they are of animal tissue rather

than plant tissue

b) slower than weeds because of the time required per genera-

tion development

c) only if they were a member of the soil insect complex

d) faster than diseases

e) faster than weeds because of relative population size and

generation time

28. A farmer can change the climate of crops by changing

a) planting date

b) tillage practices

c) planting depth

d) irrigation

e) all of the above

29. If a lot of grain graded garlicky, No. 2 for test weight, No. 3

for heat damage, No. 4 for foreign material and sample grade

for stones, then the special grade designation for the overall

lot would be

a) No. 2

b) No. 3

c) No. 4

d) Sample Grade

e) Garlicky

AGRONOMY 114 Final Exam A Page 6

30. In England, corn (Triticum aestivum) is a popular grain crop.

The primary product that corn is used for in England is:

a) ethanol

b) grits

c) malting

d) bread

e) sugar

31. I have small stipules with small petioles. The edges of my

leaf are smooth. I do not have stolons but I do have a keel and

root hairs. I am

a) barley

b) rice

c) birdsfoot trefoil

d) grain sorghum

e) Kentucky bluegrass

32. Most crops like wheat, oats, barley, and maize have a fast

transition from vegetative to reproductive growth.

Therefore, crops like these have

a) determinate growth type

b) barreness at low population

c) short-day response

d) nitrogen fixation

e) transpiration

33. What do the following herbicide terms refer to: liquid,

granular and wettable powder?

a) mode of action

b) timing of application

c) selectivity

d) formulation

e) method of plant movement

34. If you wanted to develop a new variety of field beans in the

shortest time period, you would use which plant breeding method

for the self-pollinated crops?

a) develop F1 hybrid varieties

b) pedigree selection method

c) bulk method of selection

d) synthetic variety development

e) single-seed descent method

35. An increase in what factor would probably increase nitrate

contamination of fresh water in an Iowa watershed?

a) acres of tiled land

b) acres of hay grown

c) acres of no-till

d) acres of wetland

e) acres of grass waterways

AGRONOMY 114 Final Exam A Page 7

36. Cattle egrets are an important biological control of

a) horseflies and blowflies

b) parasitic and infectious bacteria

c) Ichneumonid wasps

d) angoumois grain moths

e) wireworms

37. Bacterial blight of soybeans causes loss to the farmer due to

the

a) loss of roots causing lower seed yield

b) destruction of the translocation system causing lower yield

c) production of a toxic material

d) failure to achieve proper crop plant population density

e) destruction of leaf area, resulting in decreased

photosynthesis

38. Which term best describes the ability of a microorganism to

live on

living or dead tissue?

a) facultative

b) obligatory

c) parasitic

d) infectious

e) pathogenic

39. Which statement is not usually true for most insects in the

world

a) Some are natural pollinators

b) They are an important food source

c) Some are natural predators

d) Many are pest insects

e) They are important in nutrient recycling

40. Which crop is most likely to be injured by a period of

anaerobic conditions in the soil due to excess gravitational

water, all other things being equal?

a) maize

b) barley

c) grain sorghum

d) soybeans

e) alfalfa

41. The term "paddock" is especially relevant to

a) rotational stocking

b) deferred grazing

c) ensiling

d) grain storage

e) hay making

42. If a plant weighed 240g immediately after harvesting and

weighed 36g after drying in an oven for 8 hours, the

a) wet weight would be about 200g

b) percent dry weight would include inorganic plant minerals

c) percent wet weight would be about 6%

d) percent dry weight would be about 6%

e) total photosynthesis would be about 36g

AGRONOMY 114 Final Exam A Page 8

43. "Triple fusion" is a process associated with

a) hygroscopic water shells

b) formation of endosperm

c) the pedigree method of breeding

d) nuclear power plants

e) blending of breeder's, foundation and certified seed

44. If you crossed a John Deere tractor with a Case-International

tractor what type of baby tractor would you hope for?

a) ones that are green on the outside and red on the inside

b) ones that have the look of a John Deere but the power of a

Case-IH

c) ones that can easily hide in the grass when Case-IH tractors

drive by

d) tractors that have an excuse for not performing as well as

the CASE-IH tractors

e) all of the above could be a reason

45. Phenotype refers to

a) breeding potential of a plant

b) the performance or appearance of a plant

c) the genetic makeup of the plant

d) the chromosome content of a nucleus

e) the concentration of phenol in the cytoplasm

46. Soybean cyst nematode is most likely to overcome resistance to

a) varieties with major gene resistance

b) pubescent varieties

c) high LAI varieties

d) C4 species

e) varieties that have polygenic resistance

47. A soil with optimum conditions for plant growth would contain

the following component(s) in the given amount

a) organic matter - 25%

b) mineral matter - 5%

c) water - 45%

d) air - 25%

e) water + air - 75%

48. If a farmer harvested 150 bu of corn per acre in field A and

150 bu. of corn per acre in Field B and both are at identical

moisture, then the test weights per bushel for the two fields

a) would be identical

b) would be nearly the same

c) may differ by as much as 4 pounds/bu. or more

d) would be 60 lbs/bu at 15% moisture

e) would grade U.S. No. 1

AGRONOMY 114 Final Exam A Page 9

49. What type of crop should photosynthesize better in an

environment of low ambient levels of C02?

a) C1 plants

b) C2 plants

c) C3 plants

d) C4 plants

e) C5 plants

50. Races 1, 3, and 4 are major races of Phytophthora Root Rot in

Iowa. What does this statement mean?

a) there are at least three races of rot in Iowa soybeans

b) there are at least eight races of rot (1 + 3 + 4 = 8) in

Iowa soybeans

c) there are more than three different symptoms of Phytophthora

diseases

d) there are at least three different pathogenic organisms that

cause Phytophthora

e) there are at least four known races of the pathogenic fungal

species that causes Phytophthora Root Rot

51. What nutrient would be most limiting to high yields of

non-nodulating soybeans in an alluvial type soil in Minnesota

when no fertilizer is applied to the field?

a) P

b) K

c) CA

d) Fe

e) N

52. Which is the proper conversion for good quality silage?

a) lactic acid to sucrose

b) glucose to lactic acid

c) glucose to sucrose

d) starch to sugar

e) starch to butyric acid

53. Crops grown for use in unfavorable periods are called

a) catch crops

b) cover crops

c) sole crops

d) pulse crops

e) supplementary crops

54. Which situation is most likely to result in a killing frost on

a given day

a) moist soil, bottom land, clear sky

b) dry soil, bottom land, clear sky

c) moist soil, hillside, cloudy sky

d) dry soil, bottom land, cloudy sky

e) moist soil, south facing slope, clear sky

AGRONOMY 114 Final Exam A Page 10

55. Summer fallowing is

a) a type of plowing which involves incomplete inversion of

the furrow slice

b) planting a second crop in late summer after harvesting the

main crop

c) irrigation of a crop during the period when crop water

needs exceed precipitation

d) growing a catch crop of oats for forage before fall

planting of winter wheat

e) keeping the soil completely devoid of growth in alternate

years

56. I can fly for short distances. I grew from a nymph stage. I

like to penetrate the phloem and drink from the plant. I am a

a) braconid wasp

b) ladybird beetle

c) bean leaf beetle

d) pea aphid

e) angoumois grain moth

57. Good seed-to-soil contact is needed primarily to supply the

seed with

a) air

b) moisture

c) oxygen

d) nutrients

e) germination hormones

58. Which competitive characteristic would not be characteristic of

at least a few weed species?

a) adaptive growth

b) seed dormancy

c) gradual metamorphosis

d) thorns

e) root secretion of allelopathic substances

59. The most likely insect to cause a problem with corn

establishment because the ground was previously a smooth

bromegrass pasture is

a) white grub

b) seedcorn maggot

c) corn rootworm

d) rice weevil

e) green cloverworm

60. A sandy loam soil, compared with a silt loam soil, would

probably

a) have slower water drainage

b) have greater water holding capacity

c) remain moist for a longer period after a rain

d) warm up faster in the spring

e) have fewer sand-sized particles

AGRONOMY 114 Final Exam A Page 11

61. Salinity problems in crop production are most likely found in

what region

a) windward side of mountains

b) humid regions

c) perhumid regions

d) semiarid regions

e) lacustrine locations

62. The translocation of a herbicide from the leaves of a plant

to the rhizomes would

a) be mostly through the xylem

b) proceed along the cuticle

c) be mostly through the phloem

d) be mostly through the rachis

e) be mostly through the rachilla

63. If you were passing through east central U.S. and saw soft

red winter wheat growing, what is it likely to be used for?

a) bread

b) beer

c) pastries

d) macaroni

e) grits

64. A perfect flower is likely to be

a) self pollinated

b) on a monoecious plant

c) both self and cross pollinated

d) on a dioecious plant

e) cross pollinated

65. The most specific term describing the practice of growing

sorghum on a field for 4 successive years is

a) multiple cropping

b) monoculture

c) sole cropping

d) sequential cropping

e) relay cropping

66. What observed plant trait would be the best hint to use a

translocated herbicide rather than a contact herbicide?

a) hypogeal germinating seed

b) rapidly respiring mitochondria

c) seed produced on panicles

d) stolons

e) self pollinating flowers

67. Serveral infestation of what weed species is likely to reduce

land values for hay production?

a) Green foxtail

b) Smooth crabgrass

c) Canada thistle

d) Dandelion

e) Redroot pigweed

AGRONOMY 114 Final Exam A Page 12

68. Suppose you were asked whether a plant given to you for

inspection was a lawngrass species (Kentucky bluegrass) or a

weed in lawns. What characteristic would suggest it was a weed

species?

a) it has rhizomes

b) it has dark, green leaves

c) it has low, prostrate growth

d) it has a fibrous root system

e) it secretes a white, sticky substance

69. "The maximum amount of water the soil will hold against the

pull of gravity" is the definition for

a) maximum moisture suction

b) field capacity

c) available water

d) capillary water

e) gravitational water

70. If you were invited to a family dinner in Mexico and were

eating something that tasted like mushrooms but the fungal

material was harvested from maize, you would most likely be

eating?

a) southern corn leaf blight

b) ear rot

c) brown stem rot

d) corn smut

e) ergot

71. To properly store grain of 25% to 30% moisture, one should:

a) dry the grain to 20% moisture before storage

b) apply a dessicant to the field immediately before harvesting

c) use an air-tight storage structure

d) bring the moisture content up to 70% and pack the grain

e) dry the grain to physiological maturity immediately before

storage

72. The term that relates to the capability of the pathogen to

cause

disease is called

a) physiological potential

b) degree of disease symptoms

c) biotic rating

d) pathogenicity

e) facultative potential

73. What crop is most likely to reach harvest moisture soonest

after physiological maturity because of plant architecture and

life cycle?

a) barley

b) corn

c) grain sorghum

d) grain sorghum

e) fieldpeas

AGRONOMY 114 Final Exam A Page 13

74. If you were a consultant for a broadbean production farm and

frost killed the top 12 cm vegetative growth on one-month old

plants, then

a) the apical bud was destroyed

b) the field should be replanted

c) nitrogen fertilizer should be added to stimulate growth

d) a catch crop should be planted

e) a companion crop should be considered

75. Which one is not a service provided to farmers by the seed industry?

a) seed handling and bagging

b) varietal development

c) seed testing and labeling

d) blending seed to meet U.S. No. 2 standards

e) seed increase of new varieties

Agron 114 Final Exam Answers

(Answers may not be 100% correct; check with instructor if questionable)

Item Answer

1 3

2 5

3 5

4 5

5 3

6 5

7 4

8 3

9 2

10 3

11 2

12 1

13 2