APES Unit 4 Study Guide

How does Food Quality Protection Acts control pests?

states that the EPA must drastically decrease the allowed levels of pesticides if effects on children are unknown.

What is IPM?

(Integrated Pest Management) has the goal of reducing crop damage by viewing crops & pests as part of an ecosystem. It uses all the different methods we have discussed to prevent damage from pests, but requires expert knowledge about each crop, its pests and their interactions. Rather than just applying pesticides in case of pests, the farmer constantly evaluates the crop- pest interaction and applies new solutions as they are needed. Chemicals can be used, but only as a last resort and only those that are derived from plants. Many countries are experimenting with IPM methods (Cuba, Sweden)

What is artificial selection?

(cross breeding)-a slow process, taking usually 15 years, to produce a commercially valuable new crop variety, and it can combine traits from only species that are genetically similar

What is Industrialized agriculture?

(high input agriculture) uses heavy equipment and large amounts of financial capital, fossil fuel, water, fertilizers, and pesticides to produce monocultures (single crop). The major goal is to increase the yield (1/4th of all developed countries)

What is Slash-and-burn agriculture?

(polyculture) involves burning and clearing small plots in tropical forests, growing a variety of crops for a few years until the soil is depleted of nutrients, then shifting to other plots

What is Desertification?

(threatens world's food supply from livestock and crops)—occurs when the productive potential of soil, especially on arid or semiarid land, falls by 10% or more because of a combination of prolonged drought and human activities that red or degrade topsoil. This can result in sharp drops in food production

How can nutrients be returned to/ maintained in soil without using chemical fertilizers?

1. Crop rotation: this way, some crops will deplete nutrients and other crops will add nutrients to the soil If a farmer does need to replenish nutrients that have been lost, there are several options of organic fertilizers that can be applied to crops without causing water and air pollution. . . 2. Manure - cow poop and dead organic matter 3. "Green Manure": freshly cut or still growing vegetation that is plowed into the soil to restore nutrients by increasing the O-horizon of the soil 4. Compost: This is when organic waste material is aerobically decomposed and turned into nutrient rich soil. Composting is easy to do at home as well as on farms and it has the added benefit of reducing your trash production.

What are the environmental problems with chemical fertilizers?

1. Nitrates from fertilizers can volatilize (evaporate) into the air which can then form smog in the atmosphere. 2. Excess nitrates runoff into surface water (lakes & rivers) and cause cultural eutrophication. This is when the excess nutrients cause an algae bloom that depletes oxygen in the water as the algae die. 3. Blue Baby Syndrome: Excess nitrates can also leach through soil and contaminate groundwater (drinking water). When nitrates enter the human body they are converted to nitrites which can bind to hemoglobin and inhibits their ability to bind with oxygen and thus inhibits hemoglobin's ability to transport oxygen to body tissues.

How does a soil's moisture content relate to its texture?

A soil with a high moisture content will be much finer and dense (clay). A soil with the consistency of sand will be much dryer (sand).

What are the advantages and disadvantages of genetically modified food?

Advantages: less water less fertilizer, higher yields, grow faster, less pesticides Disadvantage: lower nutrition, harm beneficial insects, lowers genetic diversity, increase in pesticide resistant insects

What are the advantages & disadvantages of modern pesticides?

Advantages: save human lives, increase farmers profits, increase food supplies, work fast, newer methods are safer Disadvantages: accelerate development of genetic resistance to pesticides by pests, can pollute environment, threaten human health, harm wildlife, can kill natural predators that control pests

Why has meat production & consumption has increased since 1960?

Affluence is rising and middle-income people begin consuming more meat products in developing countries. As income grows, more people eat more meat which increases the demand for grain to feed the livestock.

How does industrialized agriculture threaten biodiversity?

Biodiversity is threatened when forests are cleared and grasslands are plowed up. We are replacing nature's resilient genetic diversity developed through millions of years with engineered monoculture (estimation that we have lost 3/4 of biodiversity of crops). Shortages of storage space and money limit the number of species that can be preserved and the seeds of many plants vanish.

What are porosity and permeability? How are they related to each other and a soil's texture?

Both porosity and permeability are properties directly determined by the texture of the soil Porosity: is the amount of space in between the grains of sand, silt and clay that make up the soil. Porosity is important because it determines the ease with which water, oxygen, and nitrogen can work their way down between soil particles to the root zones of plants. It also determines how quickly & easily water can soak in and become groundwater in an aquifer Permeability: describes how easily water passes through soils. It is influenced by the porosity and can be measured with a percolation test. If the permeability is too low, the soil can become waterlogged, but if it is too high, the soil can't retain enough water for plant growth. As a result the best soils for plant growth have medium-size pores or a mixture of pore sizes.

What is a CSA is and why eating locally/ seasonally can be environmentally advantageous?

CSA stands for Community- supported agriculture. When consumers join, they pay farmers in advance for a share of their yield. Consumers get fresh local produce in season and farmers get a guaranteed income. Eating crops that are produced locally and seasonally can help reduce energy inputs from industrial agriculture. Crops produced out of season can take more energy to produce and are often transported long distances. Eating locally also reduces the amount of energy needed for transporting food.

What are the advantages & disadvantages to the methods of harvesting trees (clear- cutting, strip-cutting and selective cutting)?

Clear-Cutting: this method makes good economic sense because it allows the logger to get the most money out of the land at that time. But there are some ecological problems with clear-cutting such as extreme soil erosion, loss of soil nutrients, water pollution in downhill streams, loss of habitat & loss of biodiversity in the ecosystem. Selective-Cutting: only the intermediate or older trees are cut so that some trees remain to retain the soil. This is not effective in every forest ecosystem because the logging machinery damages trees surrounding each tree that is cut. Nevertheless, selective cutting can serve to avert much of the environmental damage caused by clear cutting. Strip-Cutting: involves clear-cutting only a strip of the forest at a time, allowing it to regenerate and then cutting a nearby strip. As you can see in the picture, this prevents water pollution because trees remain in the watershed downhill of the cut strip, so they can capture and hold any soil or nutrients that run off from the cut strip.

What are the three main grains that provide most of the world's food?

Corn Wheat Rice

What are the disadvantages of raising animals in feedlots & how does raising cows on grass (instead of grain) help solve some of these problems (think back to Food, Inc)?

Cows are a lot more likely to sit in their own waste in a feedlot. The waste can then be accidentally eaten or rubbed on their bodies. Once they are slaughtered, the manure can remain on the meat contaminating it with diseases such as Ecoli. On a grass plot, cows are able to roam free and be clean. No processing needed and all organic and natural things are fed to them.

Why is eating lower on the food chain a more sustainable way to support the human population?

Eating lower on the food chain will help reduce some of the problems with industrial meat production. Additionally, it allows us to feed more people if more people are eating a plant based diet because 90% of the energy is lost at each trophic level. You can also choose more sustainable meats. For example, poultry and herbivorous fish convert grain to meat more efficiently. Cattle raised on grain are also less efficient and require more antibiotics than grass- fed cattle. Eating grass-fed beef is a more sustainable option than traditional beef.

What are the ecological/ economic services that are provided by forests?

Ecological services include the support of nutrient cycling. They also reduce soil erosion, provide habitats and promote biodiversity. Forest soils can absorb and retain water. Forests also serve to purify air and water as they take it in and then release it. Trees absorb carbon and store it while producing oxygen. Finally, trees can influence local climates through transpiration. As they release water into the atmosphere from their leaves, this increases the humidity of the air. In tropical rainforests, this is part of a positive feedback loop that maintains enough moisture in the air for rainforests to exist where they do. Forests also provide a variety of economic services. They provide fuelwood for heating and cooking, lumber and pulp for papermaking. Forests can also be used for grazing some livestock (like the farmer does with the pigs in the Omnivore's Dilemma). Finally forests provide jobs for the people who harvest

How is fire helpful in a forest ecosystem? What is the best way to prevent enormous forest fires?

Fire is a natural part of many forests and other biomes. In biomes where fires naturally occur frequently, organisms are adapted to withstand moderate fires and recover quickly. For example in most forests, fires will burn small trees and grasses and but won't damage large fire-resistant trees. In forests, some seeds/ cones will not open to germinate without fire. Fires also restore nutrients to the soil very rapidly. Therefore, these biomes need regular fires. If regular fires don't happen, underbrush will build up and when there is finally a fire, there will be more fuel, so it will burn hotter and longer. If that happens, it can even cause the fires to reach the tops of the large fire-resistant trees, causing much more damage and making it harder for the forest to regenerate. The best way to prevent big fires is prescribed burns.

How do you use a soil triangle to determine soil texture?

First calculate sand, then silt, then clay

What are the different types of pesticides are designed to kill (insecticides, herbicides, rodenticides etc)?

Insecticides: insect killers Herbicides: weed killers Rodenticides: rat and mouse killers

What is genetic engineering?

Involves altering an organism's genetic material through adding, depleting, or changing segments of its DNA to produce desirable traits or to eliminate undesirable ones. It enables scientists to transfer genes between different species that would not normally interbreed (results are GMOs).

What is the green revolution?

Involves using high-input industrialized agriculture to increase yields (involves three steps. . .) 1. develop and plant monocultures of selectively bred or genetically engineered high-yield varieties of key crops (rice, corn, wheat) 2. produce high yields by using large inputs of fertilizers, pests, and water 3. increase number of crops grown per year on a plot of land through multi cropping

What is a CAFO/ feedlot?

Large beef feedlots are also called concentrated animal feeding operations. They contain thousands of types meat all in different pens. Basically the huge corporations that are responsible for killing all the animals, a large slaughterhouse that provides them with food.

What is leaching?

Leaching is dissolved particles that move through the six horizons. Once the soil is filled with all the water it can hold, the water begins to leak downward through the layers of rock and subsoil beneath your garden. When the water sinks down, it takes soluble chemicals with it.

What is the Food Security Act?

Legal measures can be used to prevent the degradation and loss of soils. The US government enacted the Food Security Act of 1985 to preserve soil. It authorizes farmers to receive price supports and other benefits if they adopt soil conservation practices.

What are the three main nutrients that must be in soil for plant growth?

Nitrogen, Phosphorous, and Potassium are the three main nutrients that must be in soil for plant growth.

What are the main differences between old growth forest, second growth forests and tree plantations?

Old Growth: are forests that have not been seriously disturbed by humans or natural disasters for at least 200 years. They are important reservoirs of biodiversity and have been seriously depleted by human population growth. Approximately 40% of the existing forests on earth are old growth forests. Second Growth Forests: are forests that have been significantly disturbed by humans or natural disasters. They have regenerated through secondary succession and are still important ecosystems in harboring biodiversity. They make up roughly 60% of forests on earth Tree Plantations: are like man-made forests. They are also called tree farms. On these plantations, growers plant trees of one or two species and then they harvest them all at the same time, then plant more. These trees are sold and turned into wood products. There is also a lack of biodiversity since it is a monoculture, so the plantations can be very susceptible to pests. Soil can also be eroded easily when all trees are cut and habitat is destroyed when all the trees are cut. A benefit of these plantations is that they provide wood products without requiring the logging of old growth or second growth forests. Many biologists suggest only establishing tree plantations on area that has already been cleared and rather than clearing forests to plant tree plantations.

What are the names and basic characteristics of the six possible soil horizons?

One of the ways that we classify soils is by the layers, or horizons. Not all locations will have all horizons so the number of horizons present and the thickness of the layers in certain areas is one way of characterizing soils O horizon: O stands for organic. This layer is sometimes called humus and consists of decaying organic material. It is most pronounced in forest ecosystems. A horizon: is generally below the O horizon. The A horizon is a zone where minerals and organic material have been mixed together. Another name for it is topsoil. In some ecosystems, there will be no O, so the A horizon will be at the top. There are some soils that can have extra horizons because of particular properties of the soil. The E horizon (E stands for eluviation) is a zone of leaching that can sometimes be found above the B horizon in acidic soils. Due to the soil's acidity, material is more likely to dissolve and be transported down to the B horizon. B horizon: below the A horizon, also called the subsoil. This layer contains mostly inorganic material and is where nutrients will accumulate. The B horizon is present in all soils. C horizon: is below the B horizon and is the least weathered layer of soil. It consists of pieces of the parent material. R horizon: is below the C horizon and is bedrock. R stands for Rock.

What are perennial plants? How can they be beneficial in agriculture?

Perennial plants do not need to be planted each year. Perennial crops would be advantageous because their root systems would be much more developed than those of annual crops, allowing them to hold the soil in place more effectively. Annual crops have to re-grow their root systems each year, so they are not able to grow as deep into the soil. Those methods will help with soil erosion, but if soil fertility is lost, we need to find a way of dealing with that too. Most farmers will choose to add inorganic chemical fertilizers.

How does Crop rotation control pests?

Pests can be tricked—farmers can also grow crops in a different field each year; By changing planting times, even by just a week, farmers can avoid a certain life phase of a pest because pest life cycles are very short.

How do plants prevent soil erosion?

Plants provide protective cover on the land and prevent soil erosion. Plants slow down water as it flows over the land and this allows much of the rain to soak into the ground. Plant roots hold the soil in position and prevent it from being washed away.

Who is Rachel Carson & what was her contribution to environmental science?

Rachel Carson was the author of Silent Spring and was criticized by many pesticide companies, for created a wake up call to the public to focus on the potential threats for uncontrolled use of pesticides. This lead to many of them being banned for use in US and other countries

How are fire and grazers important in grassland ecosystems?

Rangeland ecosystems accumulate a large amount of detritus, mostly dead grasses, over time. This detritus is a very combustible fuel that will burn readily in the presence of fire. When fires burn this detritus, the nutrients contained in the dead plant material are returned to the soil, improving the soil quality for emerging grass plants. Additionally fire removes large grasses which shade smaller grass plants. In doing so, the fire allows more light to reach these small emerging plants.

What is rangeland?

Rangelands are grassland biomes (including chapparal) where animals can roam and graze on grasses and brush. Sometimes rangelands will be fenced in to form pastures where animals are more contained. If these lands are not good for farming, grazing animals on these rangelands is a great way to produce food from them.

What are the relative sizes of silt, sand and clay particles?

Sand is largest (0.5-2.0mm diameter) silt is in the middle (0.002-0.05mm diameter) clay is the smallest (less than 0.002 mm diameter)

What is the Conservation Reserve Program?

The Conservation Reserve Program (1985) is similar in that farmers are paid to place highly erodible land into conservation reserves. Essentially, they are paid to stop farming on some of their land and plant trees and grasses. This program saves an estimated 771 million tons of topsoil per year while generating income for farmers and promoting biodiversity by providing habitats for native wildlife.

What happened in the Dust Bowl in the 1930's in the Midwest and how does this relate to soil erosion?

The Dust Bowl of the Great Plains was a combination of extreme drought and poor soil conservation practices that led to severe wind erosion of topsoil in the 1930s. Because of the Dust Bowl, new programs arose including the Soil Erosion Act and Soil Conservation Service were implemented to decrease the effects on the soil.

What are some strategies for using rangeland more sustainably?

The best way to do this is to make sure the carrying capacity of a particular area is not exceeded. The most widely used method is rotational grazing. Ranchers use portable fencing to confine their animals to one area for 1 or 2 days. They allow them to graze and then move them to a new area to repeat the process. They are not returned to the first area until it has a chance to regenerate. Ranchers can also preserve particularly vulnerable areas, like riparian zones, by fencing them off entirely. Animals naturally head towards water, so ranchers can also protect vulnerable areas by placing watering holes, salt blocks and supplemental feed at different locations to draw the animals away from natural water sources. Finally, Environmental groups have paid ranchers to put restrictions on the deeds to their lands (conservation easements). These would prevent any future owner of the land from developing it further into houses or shopping centers

What are some disadvantages of building logging roads?

The first thing that a logging company will do is build a road which exposes soil to erosion and fragments habitats. These roads make it easier for invasive species to get into the forest (by hitching a ride with humans) and cause damage to the ecosystem. Also, roads provide a point of access for more and more people (miners, hunters, farmers etc) to get into this forested area and potentially cause damage.

Of croplands, rangelands and fisheries, which food system produces the greatest proportion of the world's food?

The greatest proportion of food comes from croplands. They produce more than 77% of the world's food.

What is the most desirable soil texture for agriculture?

The ideal soil is considered to be a loam, which is a mix of sand, silt and clay. Loams take advantage of the balance of water holding and nutrient availability between the three. Loamy soils with high organic matter are very well suited for high demand crops such as vegetables and fruit (they have different mixtures of pore sizes).

What are the three major macronutrients that humans need?

The main macronutrients that humans need are carbohydrates, proteins, and fats

What influences the speed of soil formation?

There are a number of factors that can influence the quality of the soil that forms in a particular location and how quickly that soil forms. Climate: Temperature and humidity will influence the speed of weathering. For example, in very cold climates, there will be little water movement, so physical and chemical weathering will proceed slowly. As a result, you will have underdeveloped soils that do not contain a lot of minerals or rocks. They will mostly contain poorly decomposed organic material since biological activity is also slow at these temperatures. Organisms: Burrowing animals can help to mix soil and distribute organic and inorganic components. Plants can secrete acids that can help to speed chemical weathering. Topography: steeper slopes will lose soils due to erosion, so will not have very developed soils, whereas valleys will accumulate a large amount of soils. Wind exposure or heavy rains on one side of a hill/ mountain could speed weathering as well. Parent Material: The chemical composition of the parent material (ie. basalt, limestone, granite) determines how quickly it will weather and will determine the mineral content and many other properties of the soil. Time: The more time has passed, the most developed soil will become. Old soils with productive ecosystems and moderate rainfall can become very deep and fertile (such as grasslands). However, a soil with heavy rainfall may be less fertile due to the leaching of nutrients from the soil.

What are some examples of the types of weathering that form soil?

There are three types of weathering that can contribute to soil formation. . . a) Physical weathering consists of water or wind separating piece of the rock. It can also occur when water in a crack in the rock freezes, wedging the rock apart b) Chemical weathering occurs when the rock reacts with surrounding materials, such as when a weak acid dissolves part of a rock c) Biological weathering is weathering caused by organisms such as tree roots wedging a rock apart or lichens secreting acids to dissolve a rock

What are mycorrhizal fungi? How are they important to forests?

This fungi enables plants to extract nutrients and hold onto water in very difficult soil conditions. These fungi are living organisms and will live with the plant, sourcing a continued nutrient supply for its entire lifetime. In exchange the plant provides carbon and sugars to the fungi. The overall ecosystem can benefit from higher plant diversity and improved soil structure.

What are some problems caused by deficiencies in the following micronutrients?

Vitamin A: lack of Vitamin A makes children more susceptible to common childhood infectious diseases. Some 250,000 to 500,000 children younger than age 6 go blind each year from a lack of vitamin A, and within a year, more than half of them die Iron: it is a component of the hemoglobin that transports oxygen in the blood, it causes anemia, which results in a general lack of vitality. It also causes fatigue, makes infection more likely, and increases a woman's chances of dying from hemorrhage in childbirth. Iodine: it is essential for proper functioning of the thyroid gland, which produces hormones that control the body's rate of metabolism. Chronic lack of iodine can cause stunted growth, mental retardation, and a goiter (a swollen thyroid gland that can lead to deafness).

What is weathering?

Weathering is the primary process that forms soil. Weathering breaks down the parent material, which is rock, into smaller particles. These small particles of mineral or rock combine with decomposing organic material to form soil.

How does soil form?

Weathering is the primary process that forms soil. Weathering breaks down the parent material, which is rock, into smaller particles. These small particles of mineral or rock combine with decomposing organic material to form soil. As a result, soil is neither completely biotic nor completely abiotic.

How does genetic resistance to pesticides work and what are the consequences of it for agriculture?

When a pesticide is first used, a small proportion of the pest population may survive exposure to the material due to their distinct genetic makeup. These individuals pass along the genes for resistance to the next generation. Subsequent uses of the pesticide increase the proportion of less-susceptible individuals in the population. Through this process of selection, the population gradually develops resistance to the pesticide. The consequences are that scientists have to consistently develop new pesticides that cannot be resistant to pests.

How do Hormones and Pheromones control pests?

can also be used to disrupt the life cycle of insects to prevent reproduction. These can be expensive to develop and also need to be applied with very specific timing.

How does overgrazing affects the soils of grasslands?

When the number of animals exceeds the land's carrying capacity it is called overgrazing. Some consequences of this overgrazing are that grass cover is reduced & more soil is exposed to erosion. Soil is also exposed to the trampling of animals which can compact the soil and reduce pore space. This would reduce the moisture content because there would be less pore space to hold water and it would ultimately limit the rangeland's resilience.

What are some major harmful effects of soil erosion?

a) Loss of soil and vegetation causes climate changes, the ecologic balance becomes disturbed and large amounts of natural resources are also lost. b) The soil carried by erosion fills the artificial lakes, lowering their economic lifetime. c) The farmlands become unproductive or entirely barren. The agricultural output of these regions won't be able to feed the population, and this will cause immigration which is an important cultural and economic problem

What are some of the ecosystem services provided by soil?

a) Soil provides habitats for many organisms such as bacteria, fungi, insects as well as vertebrates such as gophers b) Soil also allows for the cycling of nutrients through terrestrial ecosystems. As soil organisms break down decaying organic matter, these nutrients are returned to the soil where plants can then take them up again c) Soil provides a substrate for plant growth. Most land plants require something for their roots to grow into, so most plants would not be able to exist without soil d) Soil filters water as rainwater passes through it on its way to rivers and groundwater

What activities can lead to the destruction of topsoil?

a) flowing water b) wind c) farming d) overgrazing e) off-roading

How does FIFRA control pests?

charge the EPA with evaluating the health risks of any pesticides used in the US

What is Undernutrition?

consuming insufficient food to meet one's minimum daily energy needs for a long enough time to cause harmful effects.

What is Terracing?

creates steps on a steep slope. Crops are planted on the horizontal part of each of these steps. This retains water by controlling runoff and therefore erosion. Terracing is a method that has been done around the world for hundreds of years

What is Monoculture?

cultivating a single crop at a time

What is Malnutrition?

deficiencies of protein and other key nutrients, which wicked people and makes them more susceptible to disease and it hinders the normal physical and mental development of children

What is Food Security?

every person in a given area has daily access to enough nutritious food to have an active and healthy life

What is Traditional farming?

every unit of energy from human labor in traditional farming provides 1 to 10 units of energy

What is No-till farming?

farmers only dig a small hole in which to plant the seed. This reduces the water lost to evaporation and the fuel required to run tractors and other machinery required for tilling. It usually raises crop yields as well. However, it does require more herbicides since weeds are no longer being killed during the tilling process. It may also require more fertilizers since the weeds are no longer decomposing in the soil. No-till or reduced- till farming is becoming more common worldwide

What is Strip cropping?

form of polyculture where a farmer alternates row crops (cotton, corn) with cover crops (completely cover the soil and trap any eroding soil). Both crops are not harvested at the same time so the cover crop will continue to trap soil after the row crop is harvested

What is Polyculture?

growing several crops on the same plot simultaneously. Such biodiversity reduces the chance of losing most or all of year's food supply to pests, bad weather. . .

What is Industrialized food production?

has a net energy loss about 10 units of nonrenewable fossil fuel energy are needed to put 1 unit of food energy on the table

What is Subsistence agriculture?

mostly human labor and draft animals are used to produce only enough crops for a farm family's survival, with little left over to sell or store in hard times

What is Overnutrition?

occurs when food energy intake exceeds energy use and causes excess body fat

How do Windbreaks control pests?

provide habitats for the natural enemies of pests. When farmers practice polyculture, they can plant multiple types of plants together so that if one plant attracts a pest, another might be undesirable to the same pest.

What is Salinization?

repeated annual applications of irrigation water in dry climates that lead to the gradual accumulation of salts in the upper soil layers . This stunts growth, lowers crop yields, and kill plants and ruin land

What is Windbreaks?

similar to alley cropping except that the trees are planted around crops, instead of between them. The trees hold soil in place and block the wind to prevent wind erosion. They also retain soil moisture and provide habitats for pest-eating birds and insects

What is Waterlogging?

water accumulates underground and gradually raises the water table. Without proper drainage, this occurs and plain water envelops the deep roots of plants, lowering their productivity and killing them

What is Alley cropping?

when one or more crops are planted in between rows of trees. The trees also provide shade which retains soil moisture and reduces the need for irrigation. The trees can provide habitats for birds or other organisms that eat pests (depending on the species of tree) and the trimmings of the trees can be used as compost

What is Contour planting?

where a farmer plants with the contours of the land rather than in straight rows. Each row acts like a dam to stop soil from eroding from uphill.

What is Famine?

widespread malnutrition and starvation in a particular area because of a shortage of food, usually caused by drought, war, flood, earthquake, or other catastrophic events that disrupt this production and distribution