Deck 6: Soil and the Hydrologic Cycle

Question 1

Land drainage is beneficial because _____.

A)it increases the alternate of expansion and contraction due to freezing and thawing of soils
B)it increases the water-to-air ratio in the soil pores
C)it slows down the rate of soil warming in the spring
D)it increases the depth of root penetration in the soil
E)it increases the availability of iron and manganese in acid soils

Answer 1

D

Question 2

Which of the following would you expect to have the highest leaf area index?

A)Bare fallowed area
B)Corn three weeks after planting
C)Corn, knee high
D)Alfalfa just before harvest
E)Either B or C (equal)

Answer 2

D

Question 3

Drainage pipe comes in 200 ft long rolls.The number of rolls needed to construct a uniform buried drainage system for a nearly level 20 hectare field will depend primarily on _____________.

A)the texture and structure of the soil
B)the slope of the drain lines
C)the annual rainfall
D)rate of capillary movement in the soil
E)the saturated moisture potential of the soil

Answer 3

A

Question 4

Of the various types of drain systems, open ditch systems are most practical and economical for use on __________.

A)Vertisols
B)soils which do not freeze during the winter
C)soils with a deep water Table
D)poorly drained soils with sandy profiles
E)clay soils with poor drainage

Question 5

The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by _____.

A)the presence of macropores in the soil
B)light tillage of the upper centimeter or so of soil
C)the use of tillage to control weeds
D)the production of oats rather than wheat
E)conventional tillage as a choice compared with conservation tillage

Question 6

Which of the following will increase the evaporation (E) from the soil surface?

A)adding straw mulch to the soil surface
B)the use of no-till culture
C)stubble mulch farming
D)plastic mulch
E)none of the above

Question 7

Which of the following is not true with respect to the hydrologic cycle?

A)More than 85% of the water evaporated from the earth's surface comes from oceans.
B)There is a net migration of some 40,000 km³ of water in clouds from the land area to the ocean areas.
C)The average residence time of water in clouds is about 10 days.
D)Some 78% of the total precipitation falls onto the oceans.
E)About one third of the readily accessible water in the hydrologic cycle is in the soil.

Question 8

The expression, P - ET -SS estimates the ________ a watershed.

A)soil water content of
B)discharge volume from
C)evaporation from
D)interception in

Question 9

The water potential at the leaf surfaces expressed in kPa is most likely to be _____.

A)-10
B)33
C)-33
D)-500
E)-31,000

Question 10

The transpiration ratio of a native meadow is 550 kg per kg of dry matter produced.If 4 Mg of dry matter is produced on a hectare of land, how many centimeters of water will be required (rounded to the nearest cm) ?

A)46
B)220
C)14
D)22
E)Not possible to calculate

Question 11

Urban development of land under natural vegetation or agriculture usually greatly _____ soil infiltration capacity and therefore greatly increases _______.

A)decreases …… stream bank erosion.
B)increases …… stream bank erosion.
C)decreases …… groundwater recharge.
D)increases …….groundwater recharge.

Question 12

Which of the following irrigation systems produces the most biomass per unit of water applied?

A)flood irrigation
B)furrow irrigation
C)drip irrigation
D)sprinkle irrigation
E)furrow-dike irrigation

Question 13

Groundwater _____.

A)is a source of water above the vadose zone in a soil
B)moves downward in the vadose zone through the capillary fringe
C)moves laterally but not vertically below the soil profile
D)is found mostly in shallow layers just below the argillic
E)is a major source of water for irrigation in the United States

Question 14

Which of the following sources of water have the shortest average residence time?

A)Soil moisture
B)Clouds.
C)Oceans and ice caps
D)groundwater

Question 15

The evapotranspiration (ET) from a pine forest was found to be 50 cm during a growing season.If the evaporation from the soil surface during this period of time was 5 cm, what is the level of loss from leaf surfaces?

A)55 cm
B)45 cm
C)50.0 cm
D)10 cm
E)Impossible to calculate from the data given

Question 16

Which of the following locations in the United States would have the highest evaporation (E) from the soil surface in July?

A)a bare, unirrigated dry land soil in Colorado
B)an unirrigated soil in South Carolina growing cotton
C)a furrow-irrigated cotton field in Arizona
D)a forest woodland in Illinois
E)a corn field in New York

Question 17

Which of the following will not increase the efficiency of water use by plants in an irrigation system?

A)The use of concrete-lined delivery ditches
B)The use of flood irrigation for forage crops
C)The use of drip irrigation for fruit trees
D)The use of crop residues to reduce evaporation
E)The use of herbicides to control weeds

Question 18

In a field experiment you noted that 300 tons of water was transpired to produce 1 ton of corn (dry weight).If alfalfa had been grown in the same field instead of corn, which of the following would most likely have been the amount of water transpired?

A)500 tons
B)300 tons
C)275 tons
D)250 tons
E)depends on the climate in the area of the experiment

Question 19

If the average transpiration (T) loss from leaf surfaces in a particular watershed is 10 mm/day, you expect the evaporation (E) from the soil surface to be _____.

A)10 mm/ day
B)5 mm/ day
C)15 mm/day
D)100 mm/day
E)Impossible to calculate from the data given

Question 20

Plant transpiration efficiency at a given location is markedly influenced by _____.

A)organic residue cover on the soil
B)tillage practices used
C)fertilization practices used
D)the plant species being grown
E)both C and D

Question 21

The most common form of on-site waste water treatment for homes not hooked up to sewer lines is the _______.

A)active composting method
B)septic tank and drain field
C)chemical "flush" system
D)electrical induction sterilization
E)soil enrichment process

Question 22

Corn plants are generally more efficient in the use of water than is alfalfa.

Question 23

The average residence time for water in clouds over the ocean is about one year.

Question 24

The leaf area index significantly affects the solar radiation reaching the soil surface.

Question 25

Conservation tillage can have a significant direct effect on transpiration of water from a rapidly growing crop of corn.

Question 26

There is a net movement of clouds from land areas to the ocean areas in the hydrologic cycle.

Question 27

Drip irrigation would more likely be used in the production of apples or peaches than in the production of wheat.

Question 28

Soil and crop management generally has a greater influence on evaporation from the soil surface (E) than on transpiration (T) from leaf surfaces.

Question 29

The water potential in soils is generally considered lower than that in the atmosphere.

Question 30

Atmospheric vapor pressure has little effect on the vapor losses from soil surfaces.

Question 31

Some two-thirds of the solar energy reaching the earth is absorbed by water on or near the earth's surface.

Question 32

More than ninety-eight percent of the earth's water does not take part in the annual cycling known as the hydrologic cycle.

Question 33

Sprinkle irrigation is generally more efficient in the use of water than drip irrigation, especially for high valued crops.

Question 34

Evaporation from the soil surface (E) is determined to a large degree by soil surface wetness.

Question 35

Evapotranspiration includes vapor losses both from the soil surface and from the leaves of plants.

Question 36

Some 60 percent of the water that is actively involved in the hydrologic cycle worldwide is found in soils.

Question 37

If you dug a deep hole in your back yard and water started to seep into the hole it would fill the hole up to ________.

A)the infiltration rate
B)the percolation rate
C)field capacity
D)the water Table
E)the liquid limit

Question 38

Where high-value crops or individual ornamental shrubs are to be grown and water is expensive, the most efficient type of irrigation to use would be ______.

A)center pivot
B)basin flooding
C)furrow
D)drip or trickle

Question 39

Vapor loss from a south-facing slope in Australia would likely be higher than from a north-facing slope.

Question 40

Early snowfall that arrives before the cold winter weather has frozen the soil generally increases the penetration of water into the soil.

Question 41

Eutrophication is enhanced by the presence of pesticides in the water draining from agricultural soils.

Question 42

Recent research with annual crops such as wheat, sunflower and sorghum in the Great Plains region suggests that, compared to continuous cropping, soil quality, crop productivity and farm profitability are likely to be greater when crops are grown in a field only every second year with the soil keep free of weeds in the non-crop year by repeated cultivation of herbicide application.

Question 43

Most irrigation systems are very inefficient with less than half the water that is taken from streams ever reaching the plants.

Question 44

The pollution of ground water is often increased by the presence of macropores in soils.