E.sci Test 3

Front 1

Assume that during North America's Dust Bowl Era of the 1930s, 10 inches of top soil were either blown away or washed away through wind and water erosion. How long will it take to restore this top soil given the data I provided in this course?

Back 1

5,000 years

Front 2

by definition, top soil is what soil horizon?

Back 2

"A" horizon

Front 3

sandy loam soil consists of about ___% clay?

Back 3

20%

Front 4

in Canada, massive losses of top soil in the 1930s were due primarily to:

Back 4

wind erosion

Front 5

Given the rates of soil formation and soil erosion in "agricultural soils.ppt", how long would it take for nature to replace the top soil lost during just the first year following a forest clear-cut?

Back 5

42 years

Front 6

wild crop varieties, which are foind all around the worl, are resistant to pests, disease, early frost and drought because:

Back 6

their gene pool is rich and diverse

Front 7

"landrace" crops are

Back 7

traditional crop varieties

Front 8

of the approx. 200 domesticated plant cultivars in world, only ___& make up principal crops which today contribute about 75% of plant-derived calories

Back 8

6%

Front 9

the "rusts" which typically attack wheat plants caused by:

Back 9

fungi

Front 10

reasearch that Norman Borlaug and his plant scientist collabortors accomplished in Mexico, which started in 1943 and which led to greatly improved varieties of wheat, required ___ years of work

Back 10

19 years

Front 11

breakthrough for Borlaug in his effots to create high-yielding wheat varieties that were not subject to loding occured when he came accross a Japanese dwarf wheat variety

Back 11

true

Front 12

Norman Borlaug's research team also focused on maize production in Mexico. Many efforts were made to cross-breed maize varieties to produce high-yielding varieties of maize, but for the most part these efforts failed. Why?

Back 12

Maize is cross-pollinating. Crop improvements achieved through cross-breeding were quickly lost in just one growing season.

Front 13

Norman Borlaug and his colleagues turned to producing hybrid varieties of maize in Mexico in the 1980s. These varieties were highly productive, but farmers had to buy seed from seed factores each year. They could not save seed. Why?

Back 13

Saved hybrid seeds do not produce high yields nor do they display important traits like pest resistance.

Front 14

Why didn't Borlaug and his colleagues simply adopt hybrid corn varieties already successfully growing in the American Midwest?

Back 14

American hybrid corn would not produce high yields in Mexico for a variety of reasons including the different intensity of sunlight in Mexico versus the United States..

Front 15

Green Revolution agriculture is synonymous with Chemical agriculture.

Back 15

true

Front 16

crop irrigation is always a necessary part of Green Revolution infrastructure

Back 16

false

Front 17

Green Revolution crop varieties are less susceptible to crop disease and pest attack

Back 17

flase

Front 18

a herbicide is a pesticide

Back 18

true

Front 19

the pesticide DDT has been foiund to be relatively harmless to humans

Back 19

true

Front 20

In one study, DDT levels in zooplankton were 0.04 parts per million (ppm). But DDT levels in raptors such as eagles were much higher - 25 ppm. What would the bioconcentration factor be in this case?

Back 20

625

Front 21

which pesticide in a nerve toxin

Back 21

malathion

Front 22

which of the following best describes euthrophication

Back 22

Nutrients from agricultural runoff and/or from sewage treatment plants concentrate in receiving waters triggering algal growth. The dieoff of algal blooms creates a demand for dissolved oxygen which causes finfish and shell fish to die.

Front 23

Aquatic environments generally display dissolved oxygen levels between 5 and 12 parts per million (ppm or mg/L). If dissolved oxygen levels fall below 2 ppm, these waters are described as:

Back 23

hypoxic

Front 24

In the video featuring Dr. Vandana Shiva, it is argued that agricultural biodiversity in India is related to not only to ecosystem stability, but also to the country's economic and cultural stability. How does agricultural biodiversity contribute to the country's economy and culture?

Back 24

by creating different livelihoods for the many people needed to manage the wide diversity of crops and livestock operations

Front 25

the experience of many Canadian farmers growing genetically modified crops designedto minimize pesticide use

Back 25

crop yield have fallen and presticide use has risen

Front 26

modern methods of creating GM crops allow plants scintists to insert a gene of interest into a crop genome precisely within a DNA sequence

Back 26

false

Front 27

one out of every ___ people in the world today in a farmer

Back 27

6

Front 28

the Bayer Corp. decided in 2004 to not proceed with GM corn in the UK because

Back 28

the UK would not assume financial liability for possible enviro. problems caused by GM corn

Front 29

adding antibiotics to animal feeds used on factory farms is necessary because

Back 29

confining large numbers of animals in cages and pens creates unsanitary condtion with leads to disease

Front 30

about ____% of all antibiotics use in the US is on factory farms

Back 30

70%

Front 31

one of the following types of agriculture infrastructure cannot be used in organic farming

Back 31

chemical fertilizer

Front 32

a recent agriculture innovation by Monsanto Chemical COmpany is the chemical herbicide Roundup which kills weeds by which will not harm conventional soybean plants

Back 32

false

Front 33

delta endotoxin is

Back 33

a naturally occuring pesticide

Front 34

Sir Robert Howard of the UK is remembered as a renowned agriculture scientist because

Back 34

he learned ancient methods of organic farming from farmers in India and brought that knowledge back to Europe

Front 35

to convert from conventional agriculture to organic farming a farmer must avoid using any chemical fertilizers or chemical pesticides for ___ years

Back 35

3

Front 36

people developing societies of the world eat, on average, ___ as much meat as people in industrial societies

Back 36

3/5

Front 37

In southern China, some agricultural officials are worried about encouraging factory farm operations because:

Back 37

they fear that animal diseases may spread in this warmer part of China

Front 38

Much of today's world-wide fish catch is ground up to make fish meal which is used as an animal feed expecially in factory farms.

Back 38

true

Front 39

The two leading cereal crops used worldwide primarily as animal feed in factory farms are: .

Back 39

soybeans and corn

Front 40

cattle raised on pasture land require just as much feed grain as cattle raised in factory farms

Back 40

false