Deck 20: Prospects for Global Soil Quality As Affected by Human Activities

Question 1

The distribution of different soil orders suggests all but one of the following:

A)Most Oxisols are found in Latin America and Africa.
B)Alfisols are found mostly in semiarid areas.
C)Vertisols are most prominent in humid rainforest areas.
D)Aridisols are more extensive in Africa than in Asia and Latin America.
E)Mollisols are not very widespread in the tropics.

Answer 1

C

Question 2

Which of the following is a true statement about chemical constraints in different agroecological areas of the tropics?

A)Aluminum toxicity is most widespread in semiarid areas.
B)Highest phosphorus fixation occurs in semiarid areas.
C)The proportion of saline soils in the humid tropics is greater than in other regions.
D)Low CEC is most prevalent in acid savannas.
E)Acidity without Al toxicity is highest in the humid tropics.

Answer 2

C

Question 3

Which of the following is not a characteristic of alley cropping systems that are being studied as one alternative to slash-and-burn systems?

A)Food crops are grown in alleys with borders provided by woody species.
B)Nutrients accumulated from subsurface soil layers by the border plants are added in residues to the surface of the cropped areas.
C)The woody border plants help conserve water in the cropped alleys by shading the soil.
D)Organic mulch cut from border plants helps control weeds and prevents runoff and erosion.
E)crop yields in humid regions have generally been satisfactory using this system

Answer 3

C

Question 4

Which of the following is true of organic farming as certified in the Europe,the USA and many other countries?

A)Organic farmers are allowed to use only organic chemicals (those containing carbon).
B)Improvement of soil quality is an official goal of organic farming.
C)The burning of all plant residues is encouraged in organic farming.
D)Organic farms can use only animal manure to supply nutrients and build soil organic matter.
E)Organic farmers can use only compost made form plant materials to supply nutrients and build soil organic matter.

Question 5

Which of the following describes world food production trends?

A)From 1965 to 2005 world food production per person declined.
B)Since 1990 the increase in food production has accelerated.
C)The world food problem results from declining capacity of soils to produce food.
D)Most of the increase in food production in the last 30 years has come from increases in the area of cultivated land.
E)The world's capacity to produce food is higher today than it has ever been.

Question 6

Soils of the tropics will greatly affect future food supplies.Which of the following is correct in relation to these soils?

A)Oxisols and Ultisols dominate the semiarid areas.
B)Oxisols and Ultisols are highly leached and low in available nutrients.
C)Mollisols developed on alluvial parent materials are prized as productive rice soils.
D)Alfisols are widespread in the tropics,especially in humid areas.
E)Aridisols are scarce in the tropics,especially in Africa.

Question 7

Which of the following correctly describes human population issues pertinent to food production?

A)Populations growth is more rapid in the U.S.than in the developing countries.
B)We expect the world population to double in the next 10 years.
C)By 2025 we expect the population to reach 10 million.
D)The malnourished proportion of the population has decreased since 1970.
E)In many developing countries,the population is doubling every 10 years.

Question 8

In which region of the world does overall crop removal of nutrients significantly exceed the return of these nutrients in crop residues and chemical fertilizers?

A)Europe
B)Africa
C)North America
D)Asia
E)Latin America
True or False Questions
(Write T or F after each question. )

Question 9

Food production increases of the past 30 years have been attributed to either increases in areas of land under cultivation or increases in yields per hectare.In which region has the proportion of increased food supply attributed to increased areas under cultivation been the highest?

A)Subsaharan Africa
B)South America
C)Middle East/North Africa
D)South Asia
E)East Asia

Question 10

In recent years the annual productivity of slash-and-burn systems has tended to decline over that achieved by the traditional shifting cultivation systems of the past.To what is this decline most likely due?

A)decrease in the length of the fallow period
B)increase in the period of food production in a given cycle
C)failure to grow legumes in the cropping system
D)reduction in the C/N ratio of the soil organic matter
E)reduction in the use of fertilizers

Question 11

Which of the following was NOT an element of the Green Revolution of the 1970's and 1980's?

A)Integrated pest management to reduce the need for chemical pesticides
B)High yielding cereal varieties that responded well to fertilizers and irrigation
C)Greatly expanded use of irrigation water and chemical fertilizers
D)Monocultural systems that maximized the effects of the new varieties and technologies
E)Integration of the scientific efforts of plant breeders,soil scientists,agronomists and pest management specialists

Question 12

Shifting cultivation is characterized by _____.

A)shifting from one food crop to another in alternate years
B)alternating 2-3 years food crop production with a much longer period of fallow
C)an agroforestry system emphasizing intermixing of food crops and woody species
D)cutting and burning of woody species to reduce the C/N ratio of the crop residues
E)the shifting of land management of a given area from one farmer to another

Question 13

Which of the following is a major reason that most of the uncultivated but potentially arable lands of South America and Africa should not be used for agricultural production?

A)They are too infertile.
B)They would contribute little to meeting food requirements.
C)Their cultivation would increase global biological diversity.
D)Their cultivation would aggravate global warming.
E)They would require expensive irrigation water for high productivity.

Question 14

Which of the following are not among the major constraints on increasing food production per capita in Africa?

A)Food producing areas are far from population centers.
B)Erratic rainfall distribution and frequent droughts.
C)Very rapid increases in human population numbers.
D)Fertilizer use is very low.
E)Insufficient area of productive soils.

Question 15

In which area is the highest proportion of potentially arable land actually being cropped?

A)United States
B)Africa
C)South America
D)Asia
E)Australia

Question 16

The quality of a soil is most directly related to___.

A)its capacity to perform the functions you want it to.
B)its acidity or alkalinity of the soil
C)its resistance to soil erosion
D)its capacity to regain lost organic matter
E)its texture.

Question 17

Which of the following is NOT a likely component of the ecology-based paradigm for future intensified U.S.food production?

A)Rotation systems that enhance biological diversity
B)Organic-inorganic combinations that build active soil organic matter
C)Increased rates of nitrogen fertilizer to reduce deficiencies of this element
D)Pest management systems that minimize the use of chemical pesticides
E)All of the above are unlikely

Question 18

Which of the following contributes most positively to soil quality?

A)Monoculture cropping systems
B)Combinations of organic and inorganic inputs
C)High N and P fertilizer inputs
D)Removal of crop residues to discourage disease build-up
E)Using irrigation to raising the water table in dry regions

Question 19

Which if the following is true about a soil quality index (SQI)?

A)The SQI must be related to a particular functional goal for the soil in the ecosystem.
B)Soil pH,bulk denisty (Mg m^-3)and soil active C levels (mg kg^-1)may all be averaged together in a SQI.
C)Soil quality indices may be used to monitor the effects of changes in soil management practice over time.
D)All of the above are true.
E)None of the above are true.

Question 20

Which of the following has NOT been an effect of the intensified agriculture of the past 40 years?

A)Increased micronutrient levels in the soil.
B)Reduced need to cultivate fragile lands to produce the food required by the world.
C)Decreased biological diversity in soil systems.
D)Increased use of chemical pesticides.
E)Imbalanced human nutrition due to decreased production of edible legume crops.

Question 21

More than 75% of the potentially arable land in South America is being cultivated.

Question 22

Increasing per hectare yields of crops will likely be a more significant source of increased food production in the next few decades than will expansion of land under cultivation.

Question 23

Africa has lagged far behind other developing areas in the use of chemical fertilizers.

Question 24

Significant amounts of nitrates are adsorbed in some Oxisols by clay layers below the depths that most crop root systems can reach.

Question 25

In the past 25 years,population pressures have forced more land to come under shifting cultivation,but per hectare yields from the system have declined.

Question 26

Conservation tillage systems can decrease soil erosion and runoff and increase water infiltration in soils of the tropics.

Question 27

Alfisols are of greater importance in semi-arid tropics than in the humid tropics.

Question 28

Experts predict that the world's population will exceed 10 billion people by 2025.

Question 29

Global warming will likely be curtailed if the land area used for agriculture in South America is greatly increased.

Question 30

Alley cropping systems help control soil erosion,but crop yields are usually constrained by competition for water and nutrients between the crop plants and the border woody plants.

Question 31

During the past 30 years,per capita food production increased in developing countries of all regions but Asia.

Question 32

During the 1990s,the rate of increase of food production has declined.

Question 33

Slash-and-burn agriculture is primarily a system of water conservation and cycling.

Question 34

Many soil quality functions must be measured to define a soil quality indicator property.

Question 35

The proportion of the population of developing countries that are malnourished is higher today than it was 25 years ago.

Question 36

Worldwide,excesses and/or deficiencies of water reduce crop yields more than any other factor.

Question 37

Poor people today pay a greater proportion of their incomes for cereal foods (wheat,rice,corn)than they did just 30 years ago.

Question 38

Shifting cultivation is a relatively new cropping system,first used in the 1960s.

Question 39

There are more hungry people on Earth today than at any time in history

Question 40

Representative shifting cultivation systems today permit more soil degradation than those in use 30 years ago because the period of fallow has been decreased.

Question 41

Biofuel production form plant cellulose is likely to be a viable sustainable alternative to fossil fuel if all the entire above ground plant is harvested for conversion to fuel.