objective is to ensure the contintuity of species an ecosystems regardless of their potential utility
managing a resource so it will continue to provide maximum benefit to humans in the long run
using a resource too much. can be detrimental to ecosystem
A chemical used to kill pests
Any Chemical used to kill insects
a pesicide that kills or prevents the growth of fungus
dichlorodiphenyltrichloroethane. the first and most widely used of the synthetic organic pesticides belonging to the chlorinated hydrocarbon class.
integrated pest management
a program consisting of two or more mehtods of pest control carefully integrated and designed to avoid economic loss from pests. Its objective is to minimize the use of environmentally hazardous synthetic chemicals.
positively charged particle emitted from natural or radioactive isotopes
electromagnetic radiation emitted during radioactive decay; extremely short wavelength
electromagnetic radiation of short wavelength produced when high speed electrons strike a solid target.
Amount of time it takes for half an isotope to decay
An siotope of an element that is unstable and that gives off radioactive emissions.
Radiation that displaces ions in tissues. as it displaces them it leaves behind ions.
the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay
anything that causes cancer
Anything that can cause mutations
Side-effect of having too much nitrate or phosphate from fertilizer or sewage. Depletes amount of oxygen.
water in the ground that has filled the pores in rocks or soil
an underground layer of porous rock, sand, or other material that allows the movement of water between layers of nonporous rock or clay. Aquifers are frequently tapped for wells.
When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, this substance is called a limiting nutrient.
hot pepper powder, nicotine, citrus oil
Chlorinated Hydrocarbon pesticideex.
DDT, toxaphene,dieldrin, chlordane,lindane
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42517883656546474″ style=”font-size: medium; text-align: start; font-weight: normal;”>A vertical cross-section of the soil, exposing the various horizons.
Distinct layers within a soil that convey different properties to the soil and that derive from natural processes of soil formation. typically goes OAEBC
organic horizon, sometimes on top of A horizon in forests,made up of decaying plant residues, OAE wetlands have O over O
Surface mineral horizon, dark color due to organic residue, typically on top, humus
Horizon of eluviation, materials have been washed, light color, highly leached
Horizon of accumulation, illuviation, clay, iron, aluminum oxides washed in.
the part of soil that is comprised of air and water 20-30% water
The proportionate quantity of sand, silt, and clay in the mineral fraction of a soil-Smaller particles are more easily eroded than large ones.
Texture affects aggregation and moisture.
Effects of soil texture on the soil environment
1. movement and retention of water2.
movement of soil air
3. absorption of nutrients and pollutants4. ease of tillage
Size ranges of sand,silt, and clay
Sand 2.0 -> .05 mmSilt .05 -> .
Clay < .002 mm
the manner in which soil particles are assembled in aggregate formaggregates generally are not erodible. Aggregate stability is important.
an individual aggregate
Prismatic & Columnar
3.Blocky, angular, subangular4. Granular and Crumb5. Single-grain6.Massive
1. Clay and organic matter 2.
3. Shrinking and swelling4. Root forces5. Ice crystals.6.
Animals and insects.
7. Cementing agents (iron)
a weak attractive force that occurs between a hydrogen atom of one molecule and, usually, an oxygen atom of another molecule. it is responsible for holding water molecules together to produce the liquid and solid states.
a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries
-1/3 bar: the maximum amount of water a soil can hold against drainage
Permanant Wilting Point
-15 bar : the soil moisture level causing plants to wilt, even in cool moist air
a positively charged ion
a negatively charged ion
the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms
process in which water soaks into soil as opposed to running off the surface.
process of water seeping down through cracks and pores in soil or rock.
The Gradual breakdown of rock into smaller and smaller particles, caused by natural chemical, physical, and biological factors.
The loss of a more or less even layer of soil from the land surface due to the impact of rain and runoff from a rainstorm.
Formed from runoff water, can plow over it and hide damage
Soil erosion produced by running water and resulting in the formation of a gully.
mud flow, rainfall and water adds mass to slope, water lubricates soil particles and they take off
Saltation of the Fine Sands
-jumping and spinning motion-0.
5 – 0.05mm (diam.) fine sand
-breaks more particles loose
-silts and clays can become suspended in the air -<0.
-movement of sand dunes ->0.5 to <1.0mm
Agriculture that maintains the integrity of soil and water resources such that it can be continued indefinitely.
-Crop diversity-Raw and sod crops-legumes and Nitrogen fixation-Forages-Soil aggregation-Weed control-Insect control-Disease control
a natural process of leveling the land surface
results from human activities that disturb the soil surface and the vegetative covering of the soil. It is approximately 1000 times as fast as geologic erosion.
The layer of earths atmosphere from the surface to about 10 miles in altitude. is a well mixed site and source of our weather as well as a primary recipient of air pollutants.
The layer of earth’s atmosphere between 10 and 40 miles above the surface that contains the ozone shield. This layer mixes slowly and pollutants that enter it may remain for long periods of time
two steps involved in the process of soil erosion. Also list the various erosive agents involved in these two steps
Detachment: of individual particles from soil aggregatesTransport: of particles by erosive agents – wind or water.
Particles are eventually deposited to form new soils or to fill lakes and reservoirs.
Explain Sustainable Agriculture
agriculture that maintains the integrity of soil and water resources such that it can be continued indefinitely.Reason for concern:-population increases-Environmental concerns-Development of marginal land -Economic and political concernsAims:-Maintain and improve resource base-Protect the environment-Increase productivity-Increase profitability-Conserve energy-Improve food quality and safety-Create a viable socio economic infrastructure Features:-Crop rotation-Nutrients management-Weed control-Insect and disease control-Livestock
List methods of soil conservation that limit either detachment or transport of soil particles:
Runoff water from a field contains a small amount of decomposable organic matter. That organic matter can be measured with a 5-day BOD test. The dissolved O2 at the beginning of the test is 8 ppm. After 5 days of incubation the dissolved O2 is 1 ppm.
What is the 5-day BOD of the runoff water?
Aluminosilicate clays and humus are important sources of cation exchange capacity in soils. Why is soil cation exchange capacity important to both natural and agricultural ecosystems?
Discuss energy use and conservation.
Contrast active and passive solar heating
Active solar heating is using solar energy panels to convert sunlight into usable energy and thus power a heater. Passive solar heating is using the sun’s warmth (through windows or on thermal materials) to trap heat energy and thus heat a space through convection.
What are the alternatives to using “chemical pesticides”?
1. Biological ControlMaintenance of beneficial organisms Parasites – insect larva Predators – Lady bugs, birds Pathogens – Bacillus thuringiensisPheromone attractantsRelease of Sterile malesHormones to disrupt life cycle2. Plant extractsPyrethrins, Rotenone3. Oils and soapsPetroleum and detergents4.
Integrated pest management (IPM)
Know the biology of the pest!Crop rotationsPlanting and harvesting dates to avoid pestsBiological controlPredator – prey relationshipsIntroduction of beneficial insectsScouting for pests, monitoring populationsLimited use of pesticides when necessary
A 1000-kg car strikes a brick wall at a velocity of 2 m/s. Calculate the kinetic energy.
A 1000-kg car is parked at the edge of a 10-m cliff. Calculate the potential energy of the car (g=9.8m/s2).
What do we do about global climate change?
List the gases that cause the enhanced greenhouse effect along with their sources and sinks.
A)CarbonDioxidesources: Respiration, combustion, Burning fossil fuels (coal, oil, gas) 5,700 Tg/yr.sinks: Photosynthesis, soil organic matter, wetlands, dissolution in the oceans.B)Methanesources: Wetlands, rice paddies, ruminant animals, coal and gas production, burning, termites, landfills, aquatic systems.sinks:Reaction with tropospheric OH. Oxidation by soil microbes.C)NitrousOxidesources: Microbial N transformationsDenitrification and nitrification are sources of N2OFertilizer N and N fixationcombustionsinks: Photochemical decomposition in the stratosphere, denitrifiers.D) Chlorofluorocarbons (CFC’s)sources:Industrial synthesis, Aerosol spray cans,;foams, solvents, refrigerationsinks:;Photodissociation in the stratosphere