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.
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1. Clay and organic matter 2. Particle orientation 3. Shrinking and swelling 4. Root forces 5. 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 -<0.05mm -loess deposits
-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 aggregates Transport: 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 concerns
Aims: -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:
Limit Detachment: a. vegetative cover b. Improve soil organic matter c. reduce or eliminate tillage
Limit transport: a. reduce runoff b. increase infiltration c. rough surface d. reduce slope
Biochemical Oxygen Demand
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 Control
Maintenance of beneficial organisms
Parasites – insect larva
Predators – Lady bugs, birds
Pathogens – Bacillus thuringiensis
Release of Sterile males
Hormones to disrupt life cycle
2. Plant extracts
3. Oils and soaps
Petroleum and detergents
4. Integrated pest management (IPM)
Know the biology of the pest!
Planting and harvesting dates to avoid pests
Predator – prey relationships
Introduction of beneficial insects
Scouting for pests, monitoring populations
Limited 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
What do we do about global climate change?
List the gases that cause the enhanced greenhouse effect along with their sources and sinks.