Chapter 4

How much of the world's grain crop is fed to animals?

1/3 About a third of the grain raised is fed to animals so that we can have animal products like meat, milk, and eggs

What percentage of the world's population cannot find enough food to stay healthy?

14% About one in seven people live with food insecurity. Since there about 7 billion people currently on the planet: 1/7 = ~14%

What percentage of the food products in U.S. supermarkets contain an ingredient that has been genetically engineered?

75% 3/4 of the food products currently on U.S. supermarket shelves contain some form of genetically engineered ingredient.

Polyculture

A more sustainable crop production technique that mimics nature by promoting biodiversity, providing multiple habitats for natural predators, and assuring that if one crop is lost there are others to replace it

How does soil help us in controlling the earth's climate?

Absorbing carbon dioxide By absorbing carbon dioxide and storing it as carbon compounds, soil acts as a storage for carbon and reduces the potential for global warming

What two processes sustain the Earth's tremendous biodiversity?

Energy flow and chemical cycling Energy flows in one direction from the sun through food chains and is degraded and lost along the way. Chemicals (i.e., nutrients) are continuously recycled and reused via food chain

Since genetic engineering (GE) is limited to the transfer of genes between similar species, the main benefit of GE is that it greatly shortens the time to produce desirable characteristics.

False While genetic engineering does shorten the time span to develop a new crop variety, it allows gene transfers between different species that ordinarily could not crossbreed.

A 2008 assessment by 400 scientists concluded that genetically engineered crops have significantly increased crop yields in the U.S.

False Actually, they found the exact opposite

Crop-eating insects in monoculture fields are more vulnerable to predation.

False Since monoculture crop fields contain less biodiversity as a whole, crop eating insects are less likely to encounter natural enemies.

Traditional intensive agriculture makes use of modern farm machinery.

False Traditional intensive agriculture only uses human and animal power

Farmers that use the technique of conservation-tillage to prevent soil erosion also have the added benefit of not having to use herbicides.

False Traditional plowing and tilling is the standard method used by farmers to control weeds. If they use the no-till (conservation-tillage) approach, they must use additional herbicides to control weeds before they plant.

What is the best way to attack the root cause of food insecurity in less-developed countries?

Family planning Poverty is the root cause of most food insecurity and the best way to reduce poverty is decrease the population through family planning and empowering women. While immunizing children in those countries, reducing food waste here is the U.S., and donating more food are all good ideas, they do not address the root cause of poverty which is overpopulation

Which of the following is allowed to be used on farms that want 100% organic certification?

Fertilizers Fertilizers can be either natural (i.e., manure) or synthetic. Organic farms only use natural fertilizers

Which is the world's fastest growing form of animal food production?

Fish farms In 2010, aquaculture operations (i.e., fish farms) produced half of the all fish and shellfish consumed wordlwide and they continue to grow rapidly.

In terms of food chains, which of the following is a producer?

Grass Only plants are able to use sunlight and combine it with nutrients to produce food. Animals survive by eating plants or other animals.

A farmer has planted a field of clover as a cover crop to protect his field from erosion during the winter months. In the spring, he plows the clover into the topsoil. What kind of fertilizer does this technique create?

Green manure Green manure is freshly cut or growing vegetation that is plowed into the topsoil.

In which of these countries/places is soil erosion not a concern?

Greenland Referring to Figure 4.15, Greenland is one of the few places that does not have a designation of "serious" or even "some concern" with regard to soil erosion. This is because most of Greenland is covered with ice and, therefore, human activities have not been able to impact it

What is the best way to deal with the problem of soil salinization?

Grow less water-intensive crops. Prevention is always the best approach. In areas with high evaporation rates and high salinization potential, growing crops with low water demand minimizes the amount of salinization that occurs.

How do farmers who practice industrialized agriculture control weeds in their fields during the growing season (i.e., when their crops are growing)?

Herbicides Given their large size (thousands of acres) and dependence upon synthetic chemicals, these farmers must use regular application of herbicides to control weeds in their fields when crops are growing

What is the overdraft status of the Ogallala aquifer in northwestern Texas, eastern New Mexico, western Oklahoma, southeastern Colorado, and southwestern Kansas?

High In the states listed, the Ogallala is being overpumped 10 to 40 times faster than it can be recharged. See Figure 4.18.

What advantage do most annual plants (raised using a monoculture approach) have over perennial crops (raised using a polyculture approach)?

Higher yield So far, the major challenge of perennials has been in matching or exceeding the yield produced by annual crops

Desertification

In the Sahel region of West Africa, this process is causing the removal of topsoil and loss of farmland due to human activities and prolonged drought.

Which best describes a community-supported agriculture program?

Individuals pay a set amount to get a certain amount of produce from a local farmer once a week. Community-supported agriculture program help local farmers to be supported by their community by having "subscribers" that guarantee to pay a set fee over the course of the growing season in exchange for regular distributions of locally-grown food.

What agricultural method produces the most food?

Industrialized agriculture Industrialized agriculture produces 80% of the world's food on ~25% of the word's farmland.

Which agricultural practice is considered high-input?

Industrialized agriculture Industrialized agriculture relies on large inputs of irrigation, fertilizers, pesticides, and machinery and is thus called high-input agriculture

Crossbreeding

The process of selecting individual plants and pairing them for reproduction to produce offspring with desirable characteristics is called

What have humans done to maintain high crop yields?

They have developed synthetic versions of nutrients to help crops grow. Nitrogen is a limiting nutrient in natural systems. Since plants cannot absorb it directly from the air, it has to be converted by natural processes which can take a long time. Man has learned to speed up this process by transforming nitrogen gas to the nitrate ion.

What is the main problem with using broad-spectrum pesticides?

They kill crop-eating and beneficial insects. Broad spectrum pesticides are indiscriminate and kill all insect species.

Persistent

This pesticide does not degrade after being sprayed and remains in the environment for years causing long-term problems.

Which statement about topsoil is correct?

Topsoil is a renewable resource but, since the renewal process is very slow, topsoil is easily depleted by human actions. Topsoil is a mature, fertile soil that plants need to prosper. It is renewable, but at a time scale that is much slower than the time it takes for it to be depleted by human actions.

Integrated pest management (IPM) is a great way for farmers to reduce pesticide use and save money in the long term, but it does not work in every situation.

True IPM requires an expert knowledge of pests, training and time. Some farmers may not have the resources to devote to this approach and may rely instead on more simple options like conventional spraying

Industrialized agriculture has led to a serious decline in agrobiodiversity.

True Industrialized crop production is a form of large scale monoculture that relies on just a few varieties of each food crop. Many varieties of crops have been lost due to the green revolution that promoted production over biodiversity.

Most organisms are involved in multiple food chains.

True Most organisms eat, and are eaten by, several different types of other organisms and are involved in many different food chains that are collectively called food webs.

The widespread use of insecticides has transformed some crop eating insects that were previously minor pests into highly destructive species.

True Pests that were previously considered minor ones have survived exposure to pesticides and passed on that genetic resistance to their offspring. Since pesticides kill both destructive and beneficial insects, the beneficial population has been decimated allowing the minor pests to be become major pests

Most of the people in the U.S. are considered to be overweight.

True Two out of every three citizens of the U.S. are overweight, according to the U.S. Center for Disease Control

Which of these countries would you find the highest percentage of the total population suffering from overnutrition?

United States Most people in more-developed countries, like the U.S., do not have to worry about food security. The main danger for them is too much food.

Which action is responsible for leaving the largest areas of topsoil unprotected and thus vulnerable to erosion?

Agriculture Natural processes like wind and water can accelerate soil erosion, but they don't typically leave soil uncovered for long. After a season, they allow vegetation to recover and prevent the loss of soil. In contrast, agriculture is an ongoing process that repeatedly leaves soil devoid of vegetation and unprotected.

Which of the following food chains will have the greatest loss of chemical energy?

Algae > minnow > bass > bear > decomposer The more trophic levels there are in food chain, the greater is the loss of chemical energy

What method is specifically designed to reduce soil erosion caused by runoff of rain water?

Contour planting Contour planting is used on sloped land and involves plowing along the contour of the land and creating a series of micro-terraces that trap and reduce the downhill movement of runoff.

A hundred years ago, how did farmers develop new varieties of squash to resist the squash borer insect pest?

Crossbreeding Crossbreeding, also called artificial selection, is a technique where plants with desirable traits are paired to produce seed. By pairing squash plants that were more resistance to the borer, they could produce a superior variety over time

A farmer decides he will wait until the number of crop-eating insects gets large enough to create economic damage before he takes action. When that occurs, he will first try natural biological controls. If that does not work, he will use less harmful biopesticides in small amounts to target specific species; and then only use synthetic chemicals if he has no other choice. What is this approach called?

Integrated pest management Integrated pest management uses a pest control approach that treats each crop and its pests as parts of an ecological system. Instead of indiscriminate spraying like conventional approaches, it targets specific pests with a tailored approach

Which of these practices causes salinization of farmland?

Irrigation Irrigation is used primarily on farmlands in arid areas. The soils in these areas tend to contain high levels of mineral salts that are dissolved by the irrigation water. Not all of the irrigation water is absorbed by the plants; so some of the water evaporates leaving behind concentrated salt compounds in the soil.

When excess nitrogen from industrialized agricultural fields enters rivers as runoff, which of the following happens first?

It promotes the growth of algae. While the end result is oxygen depletion and fish kills, the dissolved nitrogen (in the form of nitrate) first stimulates the growth of large amounts of algae. When the algae dies, anaerobic bacteria consume it and deplete the oxygen in the water. After the dissolved oxygen is depleted the fish die

What will contain the highest biodiversity?

Mature A horizon soil The higher the amount of organic matter, the higher the biodiversity. Mature soils have a higher organic content than Young or Immature soils, and the A horizon is richer than the C horizon. See Figure 4.3.

What known greenhouse gas is released from manure at large animal feedlots?

Methane Manure emits large amounts of methane. Large amounts of fossil fuels are consumed to maintain these feedlots and that contributes to the amount of carbon dioxide in the atmosphere.

Which is a sustainable way of harvesting fish on a commercial scale: industrialized fishing or aquaculture?

Neither are sustainable on a commercial scale Industrialized fishing is not just overfishing the oceans but reducing biodiversity and causing great harm to ocean floor habitats by trawlers. Aquaculture (fish farming) appears on the surface to be a better alternative but it introduces other negative environmental impacts: polluting the water with fish wastes and antibiotics, destroying habitats to construct the farms, and depleting wild fish stocks to feed the farm-raised fish.

What is it called when water is withdrawn from an aquifer faster than it can replaced?

Overpumping Overpumping of aquifers occurs when the pumping rate exceeds the recharge rate

Which of these options is the most sustainable way to produce more food?

Polyculture Of the choices offered, only polyculture offers a sustainable approach to this problem. Polyculture uses water and nutrients more efficiently, rarely requires the use of pesticides, and can produce higher yields than monoculture.

What is the main cause of food insecurity?

Poverty According to many food security experts, poverty limits the ability of people to either buy or grow enough food which creates food insecurity

If you live in the U.S. and shop at a typical large food store, what should you eat if you want to minimize your environmental impact from the agricultural system?

Rice As shown in Figure 4.31, you must feed an animal more grain than it will produce in terms of body weight. Raising animals means more land must be farmed and the most common type of farming in the U.S. is industrialized agriculture (which causes significant environmental impacts). Given that, you should just eat the grain (rice).

Of the following choices, which kills the most crop-eating insects each year?

Spiders Most insect species are kept in control by natural predators and spiders compose the largest group of natural insect predators.

An organic farmer is Kansas just found out that a neighboring farm is using genetically modified (GM) seeds. Why should he be concerned?

The DNA from the GM plants will contaminate his crop. Contamination of the genetic material (DNA) of crops grown by organic farmers by GM crops is widespread and threatens the livelihood of the organic grower.

Green revolution

The agricultural movement that has boosted yields by (1) developing high-yield varieties, (2) using large inputs of water and fertilizer, and (3) multiple cropping is called