Unit 4 Test
What are the names and basic characteristics of the six possible soil horizons?
#1 O-horizon: decomposed organic matter made mostly of leaf litter and humus #2 A-horizon: top-soil made of humus and mixed with mineral particles #3 E-horizon: leeching layer, light in color, mostly made of sand and silt #4 B-horizon: sub-soil and contains clay and mineral deposits #5 C-horizon: regolith, made of slightly broken up bedrock with very little organic matter #6 R-horizon: made of bedrock
Name some of the ecosystem services provided by soil.
-Surface for plants to grow on -Nutrient Cycling -Habitat -Filters water
Know the main ways that food can be grown to promote soil conservation.
-Terracing -Strip cropping -Contour planting -Alley cropping/windbreaks -No till farming
What are the environmental problems with chemical fertilizers?
-Algae boom; use up all of the oxygen in water. -Contamination of ground water -Smog -Blue Baby Syndrome due to contaminated with nitrates -Cultural Eutrophication --> leads to increase in turbidity -leads to hypoxic conditions
What activities can lead to the destruction of topsoil?
-Destroying soil/Holding grasses -Farming, clear-cut logging -Overgrazing -Off-road vehicle use
What are the disadvantages of building logging roads?
-Exposes soil to erosion -Fragments habitats -Make it easier for invasive species to get into the forest (by hitching a ride with humans)
What are the two major harmful effects of soil erosion?
-Loss of soil fertility through depletion of plant nutrients. -Water pollution in nearby surface waters, where eroded soil ends up as sediment.
How is fire helpful in a forest ecosystem?
-Restores nutrients to the soil very rapidly -Causes some seeds to germinate -Gets rid of detritus and build up (eliminates fuel for much larger, dangerous fires) -Encourages biodiversity, adaptation, and growth (makes plants regrow back faster and faster)
Who is Rachel Carson and what was her contribution to environmental science?
A biologist that greatly increases our understanding of the importance of nature and the harmful effects of widespread use of pesticides.
What are the disadvantages of raising animals in feedlots and how does raising cows on grass rather than grain help solve some of these problems?
Animals are more prone to heat stress, which can cause death and they can also get bloat or liver sores. Creates huge energy and oil costs for transporting grain and uses chemical fertilizers; polluted environment and very bad for animals (plus inhumane). Raising cows on grain causes them to develop ecoli. Raising them on grass causes them to be less fatty and healthier, in addition to not developing bad diseases that can be transmitted to humans.
What are the advantages and disadvantages to clear-cutting?
Advantages: Allows the logger to get the most money out of the land at that time. Disadvantages: Ecological problems such as extreme soil erosion, loss of soil nutrients, water pollution in downhill streams, loss of habitat & loss of biodiversity in the ecosystem
What are the advantages and disadvantages to selective cutting?
Advantages: Can serve to avert much of the environmental damage caused by clear cutting. Disadvantages: Eliminates a specific type of tree.
What are the advantages and disadvantages of genetically modified food?
Advantages: Need less fertilizer, need less water, more resistant to insects, disease, and drought, grow faster, can grow in slightly salty soils, may need less pesticides, can tolerate higher levels of herbicides, higher yields, less spoilage. Disadvantages: Irreversible and unpredictable genetic and ecological effects, harmful toxins in food from possible plant cell mutations, new allergens in food, lower nutrition, increase in pesticide-resistant insects and herbicide resistant weeds, plant diseases, can harm beneficial insects, lower genetic diversity.
What are the advantages and disadvantages to strip-cutting?
Advantages: 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. Disadvantages: Eliminates riparian communities.
What is artificial selection?
Artificially selecting certain traits via crossbreeding and genetic engineering. Evolution not natural; man imposed. Allows farmers to improve crops to have traits beneficial to us.
How does a soil's moisture content relate to its texture?
Based on our texture and moisture and permeability data, it would appear that smaller particles hold the most water (most porous) and are the least permeable, simply because it is harder for water to drain out of them due to the particles being so close together. Clay has smaller spaces between the particles but has more pores, and thus has higher porosity than sand. Larger particles such as sand are less porous but more permeable since there is more space for the water to drain through (lower porosity due to having less pores overall but more space in each pore; water can thus travel more easily through the particles, making it more permeable). I would expect clay, silt, and other soils to have the highest moisture content because they are much closer together than sand is, and thus it is harder for water to move through the particles. In addition, clay/silt/soil would have the lowest permeability because it is so hard for the water to travel through the many pores.
Why has meat production and consumption increased since 1960?
Because people have become more affluent (gained wealth) and want to produce more meat faster.
What is the best way to prevent enormous fires?
By having periodic smaller fires to burn away all the plant detritus (prescribed burns are most effective, healthy way).
What is a CSA and why can eating locally/seasonally be environmentally advantageous?
CSA = 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.
What is malnutrition and what health problems are associated with this condition?
Deficiencies of protein and other key nutrients. Weakens them, makes them more susceptible to disease, hinders physical development and mental development of children.
What is leeching?
Dissolved particles move down through horizons. Occurs in the E horizon.
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.
What is a CAFO/feedlot?
Feedlots/confined animal feeding operations = animals are fed grain or meal product from fish; fattened up in crowded cages and slaughtered.
What are the basics of the Food Security Act and the Conservation Reserve Program?
Food Security Act: Farmers that adopt soil conservation plan receive price supports and other benefits. Conservation reserve Act: Pays farmers to not farm if their land is highly erodible or degraded.
How can nutrients be returned to/maintained in soil without using chemical fertilizers?
Genetically engineer crops with lower fertilizer requirements, crop rotation/polyculture; alternate nutrient-depleting crops with crops that supply nutrients, organic fertilizers (manure compost, "green manure"). Note: beans add nitrogen to the soil through the process of nitrogen fixation.
What are the relative sizes of silt, sand, and clay particles
Grain size is classified as clay if the particle diameter is <0.002 mm, as silt if it is between 0.002 mm and 0.06 mm, or as sand if it is between 0.06 mm and 2 mm.
Explain how overgrazing affects the soils of grasslands.
Grass cover is reduced and more soil is exposed to erosion. Soil is also exposed due to the trampling of animals which can reduce pore space in the soil. This would reduce the moisture content as there would be less space to hold the water and it would negatively impact the rangeland's resilience.
What is rangeland?
Grassland biomes (including chaparral) where animals can roam and graze on grasses and brush.
How are fire and grazers important in grassland ecosystems?
Grazing stimulate plants to grow and eliminate mature growth. Fires eliminate plant detritus, return nutrients to the ground, and encourage biodiversity/growth.
Define industrialized agriculture.
High input agriculture; uses heavy equipment and large amounts of financial capital, fossil fuel, water, commercial fertilizers yield of a crop. Plantation agriculture is another form; grows cash crops. Greenhouses also used.
What happened in the Dust Bowl in the 1930's in the Midwest and how does this relate to soil erosion?
In the 1930s dust clouds created by hot, dry windstorms blowing across the barren exposed soil darkened the sky at midday in some areas. Rabbits and birds choked to death on the dust. Killed livestock; caused thousands of farm families to migrate. Caused because much of the topsoil in several dry and windy Midwestern states was lost because of a combination of poor cultivation practices and prolonged drought. Result of overgrazing and plowing.
How does industrial agriculture and traditional farming compare in terms of the amount of energy required to get 1 unit of food energy to the table (and why are these values different)?
Industrialized food production takes 10 units of fossil fuel energy to make 1 unit of food energy, whereas traditional farming takes 1 unit of fossil fuel energy to make 10 units of food energy. This is because industrialized food production has high inputs due to loss of soil nutrients.
What are insecticides designed to kill. herbicides designed to kill, rodenticides designed to kill, and etc? P.294
Insecticides are designed to kill insects, herbicides are designed to kill weeds, rodenticides kill rats and mice.
What is IPM?
Integrated Pest Management: Reduces (rather than eliminates) crop damage by viewing crops and pests as part of an ecosystem; utilizes a variety of pest control methods.
What is genetic engineering?
Involves altering an organism's genetic material through adding, deleting, or changing segments of its DNA to produce desirable traits or eliminate undesirable ones. Called genetically modified organisms or transgenic organisms.
Define-slash-and-burn agriculture.
Involves burning and clearing small plots in tropical forests, growing a variety for a few years until the soil is depleted of nutrients, then shifting to new plots.
What problems are caused by deficiencies in iodine?
Iodine is essential for proper functioning of the thyroid gland, which produces hormones that control the body's rate of metabolism. Lack of iodine can cause stunted growth, mental retardation, and goiter (a swollen thyroid gland that can lead to deafness). 600 million suffer from goiter, and 26 million children suffer brain damage.
What problems are caused by deficiencies in iron?
Iron is a component of hemoglobin that transports oxygen in the blood. Having too little iron causes anemia, which results in a general lack of vitality. Causes fatigue, makes infection more likely, and increases chance of women dying from hemorrhage in child birth.
What are the advantages and disadvantages of modern pesticides?
Kill wrong organisms (wipe out tens of millions of bees, fish, and birds). poision millions of people, kills tens of thousands. Causes 5-10$ in damages to environment for every dollar spent on pesticides. Benefits: Increased food production, increased profit, and the prevention of diseases/pests.
What is the most desirable soil texture for agriculture?
Loam.
What is the general info about the climate, location and soil in a chapparal?
Long and warm dry summers, slightly mild wet winters, long winter rainy season. The soil is thin and not very fertile, and the chaparral is typically located about 30-40 degrees North or South.
What is the general info about the climate, location and soil in a temperate deciduous forest?
Moderate average temperatures; long warm summers, cold but not severe winters, and abundant precipitation spread throughout the year.
What is the general info about the climate, location and soil in a temperate grassland (savanna)?
Moderate climate, half-way between the equator and the poles (about 45 degrees North or South). Nutrient rich soil.
What are mycorrhizal fungi? How are they important to forests?
Mutualistic plants that cycle nitrogen and phosphorous (among other nutrients) to other plants in the community. Grow on a host plant and both are benefited. Allows plants to communicate via hormones.
What is organic agriculture and why is it more sustainable? Provide specific reasons.
Natural agricultural; no pesticides, no synthetic fertilizers. It maintains the environmental health and reduces pollution; creates biodiversity. Basically sustains healthy soil by eliminating high inputs.
What are the three main nutrients that must be in soil for plant growth?
Nitrogen, Phosphorous, and Potassium.
What is overnutrition and what health problems are associated with this condition?
Occurs when food energy intake exceeds energy use and excess body fat. Too many calories, too little exercise, or both can cause overnutrition. Associated with lower life expectancy, greater susceptibility to disease/illness, and lower productivity/life quality.
Define desertification and explain the consequences of it.
Occurs when the productive potential of soil, especially on arid or semi arid land, falls by 10% or more because of a combination of prolonged drought and human activities that reduce or degrade topsoil. Leads to a decrease in yields, soil fertility, and decrease in biodiversity.
What are the main differences between old growth forest, second growth forests, and tree plantations?
Old growth forests = More than 200 years without being disturbed (by humans mainly; also natural disasters like fires). Second growth forests = Gone through secondary succession; been destroyed and grew back. Tree plantations = Grow trees on farms; cut them all down. Privately owned; for timber production.
How does genetic resistance to pesticides work and what are the consequences of it for agriculture?
Organisms that are not resistant die out; ones with resistance survive and reproduce; develop immunity through natural selection. Causes more of the food supply to be lost from pests not being killed.
What is undernutrition and what health problems are associated with this condition?
People who cannot grow or buy enough food to meet their basic needs; hunger. Mental retardation, stunted growth, and common un-severe diseases such as diarrhea kill them.
What are perennial plants? How can they be beneficial in agriculture?
Perennial plants are plants that last multiple seasons. They hold the soil better because the roots grow every year, rather than having to be constantly dug up and regrown like annual plants such as pumpkins and carrots. Reduce soil erosion.
What is weathering?
Physical and chemical processes in which solid rock exposed at earth's surface is changed to separate solid particles and dissolved material, which can be moved to another place as sediment.
Give examples of the types of weathering that form soil.
Physical weathering (swiftly moving water), chemical weathering (oxidation; iron oxide) and biological weathering (tree roots prying rock apart or plant acids dissolving rock).
What is the difference between polyculture and monoculture and why polyculture is more sustainable.
Polyculture = growing several crops on the same plot simultaneously; Monoculture = growing only one crop. Polyculture reduces the chance of losing most of all of the year's food supply to pests, bad weather, and other misfortunes thanks to crop diversity.
What are porosity and permeability? How are they related to each other and a soil's texture?
Porosity is a measure of how much of a rock is open space. This space can be between grains or within cracks or cavities of the rock. Permeability is a measure of the ease with which a fluid or gas (water in this case) can move through a porous rock. Porosity depends on both soil texture and structure. For example, a fine soil has smaller but more numerous pores than a coarse soil. Soil texture and structure greatly influence water infiltration, permeability, and water-holding capacity. Soil texture refers to the composition of the soil in terms of the proportion of small, medium, and large particles (clay, silt, and sand, respectively) in a specific soil mass.
Define salinization and explain the consequences of it.
Process in which irrigation water that has not been absorbed into the soil evaporates, leaving behind a thin crust of salts in the top soil. Repeated annual applications of this degrade the soil. Puts stress on plants.
What is the green revolution?
Process to increase yields. 1st: develop genetically engineered high yield monoculture. 2nd: produce high yields by large inputs of fertilizers, pesticides and water. 3rd: increase number of crops grown on a plot per year using multi cropping.
How do plants prevent soil erosion?
Roots of plants help anchor the soil, and the soil stores water rather than being pushed around by it.
What are some alternative ways of controlling pests (P.299)?
Rotating the crops in a field each year; fool the pests. Provide homes for pest enemies via polyculture. Implant genetic resistance. Bring in natural enemies; biological control. Use insect perfumes; sex attractants (pheromones). Bring in hormones. Scald them.
What are some strategies for using rangeland more sustainably?
Rotational grazing (animals only allowed to eat in one area at a time and do not return until that area has regrown), Stop excessive water consumption (causes riparian community to grow back), Regulate irrigation.
Be able to use a soil triangle to determine soil texture (Soil Triangle Practice Problems) 1. Find the texture of a soil with 50% Sand, 20% silt, 30% clay 2. Find the texture of a soil with 5% Sand, 80% silt, 15% clay 3. Find the texture of a soil with 80% Sand, 15% silt, 5% clay 4. Find the texture of a soil with 50% Sand, 10% silt, 40% clay 5. Find the texture of a soil with 20% Sand, 60% silt, 20% clay
See hand out
Be able to read a climatograph!!! Review the climatographs for different biomes.
See page 149 (image on iPhone). MAKE SURE TO DO THIS!!! GOT THIS WRONG ON PREVIOUS TESTS
How does time influence soil formation?
Soils can take many years to form. Younger soils have some characteristics from their parent material, but as they age, the addition of organic matter, exposure to moisture and other environmental factors may change its features. With time, they settle and are buried deeper below the surface, taking time to transform. Eventually, they may change from one soil type to another.
What are the ecological/economic services that are provided by forests?
Support nutrient cycling, reduce soil erosion, provide habitats and promote biodiversity. Forests purify air and water, store carbon, and forest soils absorb/retain water. They also maintain the humidity through transpiration.
How do organisms influence soil formation?
The source and richness of organic matter are down to the living things (plants and animals) that live on and in the soils. Plants, in particular, provide lots of vegetative residues that are added to soils. Their roots also hold the soils and protect them from wind and water erosion. They shelter the soils from the sun and other environmental conditions, helping the soils to retain the needed moisture for chemical and biological reactions. Fungi, bacteria, insects, earthworms, and burrowing animals help with soil aeration. Worms help break down organic matter and aid decomposition. Animal droppings, dead insects and animals result in additional decaying organic matter. Microorganisms also help with mineral and nutrient cycling and chemical reactions.
How does climate influence soil formation?
This is probably the most important factor that can shape the formation of soils. Two important climatic components, temperature and precipitation are key. They determine how quickly weathering will be, and what kind of organic materials may be available on and inside of the soils. Moisture determines the chemical and biological reactions that will occur as the soils are formed. A warmer climate with more rainfall means more vegetative cover and more animal action. It also means more runoff, more percolation and more water erosion. They all help to determine the kind of soils in an area.
How does topography influence soil formation?
This refers to the geography of the surface. Steep, long slopes mean water will run down faster and potentially erode the surfaces of slopes. The effect will be poor soils on the slopes, and richer deposits at the foot of the slopes. Also, slopes may be exposed to more direct sunlight, which may dry out soil moisture and render it less fertile.
Define subsistence agriculture.
Traditionally uses mostly human labor and draft (working) animals to produce only enough crops for a farm family's survival, with little left over to sell or store as a reserve in hard times.
Define waterlogging and explain the consequences of it.
Water accumulates underground and gradually raises the water table. Without proper drainage, waterlogging occurs and saline water then envelops the deep roots of plants, lowering their productivity and eventually killing them. Farmers often apply large amounts of irrigation water to leach salts deeper, causing waterlogging.
How has industrialized agriculture threatened biodiversity?
We have lost 3 fourths of the genetic diversity of agricultural crops.
What are the three main grains that provide most of the world's food?
Wheat, rice, and corn. Provide 47% of the calories and 42% of the protein people consume. 2/3 of world population survive on primarily these 3 grains.
What is the general info about the climate, location and soil in a taiga forest?
Winters are long, dry, and extremely cold. Summers are short with cool-warm temperatures. 6-8 hours of sun in winter, 19 during summer. Soil is is mostly frozen and has a deep layer of partially decomposed conifer needles. Soil is nutrient poor and acidic (from the needles). Occurs between latitudes of 60 degrees North or South.
What problems are caused by deficiencies in vitamin A?
Without it, a person is more susceptible to common childhood infectious diseases. Can go blind without it and even die. 250k-500k under 6 years old go blind each year and more than 50% die.
What is the general info about the climate, location and soil in a tropical rianforest?
Year round uniformly warm temperature. Heavy rainfall almost daily, high humidity. Soil not very nutritious. Occurs between latitudes of 0 degrees.
