Land and Water Use

1st Green Revolution
(1950-1970) It invloved planting monocultures, using high applications of inorganic fertilizers and pesticides, and widespread use of artificial irrigation systems. Crop acrege increased about 25% and crop yield increased 200%.
2nd Green Revolution
(1970s-today) It involves growing genetically engineered crops that produce more yield per acre.
Pros of Genetically Engineered Crops
– May require less water and fertilizer
– Higher crop yields
– Less spoilage
– Faster growth which may mean greater productivity, resulting in lower operating costs
– More resistant to disease, drought, frost, and insects
– May be able to grow in saltier soils
Cons of Genetically Engineered Crops
– Unknown ecological effects
– Less biodiversity
– May harm beneficial insects
– May pose allergen risk
– May result in mutations with unknown consequences
– may cause pest-resistant strains
Cons of Genetically Engineered Crops
– Unknown ecological effects
– Less biodiversity
– May harm beneficial insects
– May pose allergen risk
– May result in mutations with unknown consequences
– may cause pest-resistant strains
Biological Pesticides
Living organisms are used to control pests. (Examples: bacteria, ladybugs, parasitic wasps, and certian viruses)
Carbamates (Urethanes)
Pesticides that affect the nervous system of a pest. 100 grams have the same effect as 2,000 grams of chlorinated hydrocarbon. They are more water soluble which brings a greater risk of them being dissolved in surface water and going into the ground water.
Chlorinated Hydrocarbons
Synthetic Organic compounds that affect the nervous system of pests. They are highly resistant to decomposition and can remain in the ecosystem for up to 15 years. (DDT)
Fumigants
Used to sterilize soil and prevent pest infestation of stored grain.
Inorganic Pesticides
Broad-based pesticides. Includes arsenic, copper, lead, and mercury. Highly toxic and accumulate in the environment.
Organic or Natural Pesticides
Natural poisons derived from plants such as tobacco or chrysanthemum.
Organophosphates
Extremely toxic but remain in the environment for only a short time. Ex: malathion and parathion
Pros of Pesticide Use
– Kill unwanted pests that carry disease
– Increase food supply
– More food means food is less expensive
– Newer pesticides are safer and more specific
– Reduces labor costs
– Agriculture is more profitable
Cons of Pesticide Use
-Accumulates in food chains
– Pests develop resistance and create a pesticide treadmill
– Estimates range from $5 ot $10 in damage done to the environment for every $1 spent on pesticides; pesticides are expensive to purchase and apply
-pesticide runoff and its effect on aquatic environments through biomagnification
– Inefficiency- only 5% of a pesticide reaches a pest
– Threatens endangered species and pollinators; also affect human health
Methods of Integrated Pest Management (IPM)
1. Polyculture 2. Intercropping 3. Planting pest-repellent crops 4. Using multch to control weeds 5. Using pyrethroids or naturally occurring microorganisms (such as Bt) instead of toxic pesticides 6. Natural insect predators 7. Rotating crops often to disrupt insect cyclyes 8. Using pheromones or hormone interrupters 9. Releasing sterilized insects 10. Developing genetically modified crops that are more insect resistant 11. Regular monitoring through visual inspection and traps followed by record keeping 12. Construction of mechanical controls such as traps, tillage, insect barriers, or agriculture vacuums equipped with lights
Federal Insecticide, Fungicide and Rodenticide Control Act (FIFRA)
(1947) Regulates the manufacture and use of pesticides. Pesticides must be registered and approved. Labels require directions for use and disposal.
Federal Environmental Pesticides Control Act
(1972) Requires the registration of all pesticides in US commerce.
Food Quality Protection Act (FQPA)
(1996) Emphasizes the protection of infants and children in reference to pesticide residue in food.
Ecological Services of Forests
1. Provide wildlife habitats
2. Carbon sinks
3. Affecting local climate patterns
4. Purifying air and water
5. Reducing soil erosion as they serve as a watershed, absorbing and releasing controlled amounts of water
6. Providing energy and nutrient cycling
Crown Fires
occur in forests that have not had surface fires for a long time. Extremely hot. Burn entire trees and leep from treetop to treetop. Kills wildfire, increases soil erosion, and destroys structures.
Ground Fires
Fires that occur underground and burn partially decayed leaves. Common in peat bogs. Difficult to decay and distinguish.
Surface Fires
Burns undergrowth and leaf litter. Kills seedlings and small trees. Spares older trees, and allows many wild animals to escape.
Advantages of Surface Fires
Burns away flamable ground litter, reducing larger fires later; releases minerals back into soil profile; stimulates germination for some species with serotinous cones, helps to keep pathogens and insects in check and allows vegitation to grow in clearings.
Pros of Tree Plantations
– Practical method for trees that require full or moderate sunlight in order to grow.
– Genetically inproved species of trees that resist disease and grow faster can be grown
– Increases economic returns on investment
– Produces a high yield of timber at the lowest cost, and provides jobs.
Cons of Tree Plantations
– Reduces the recreational value of the land
– If done on steeply sloped areas, will often cause soil erosion, water pollution and flooding.
– Causes habitat fragmentation
– Reduces biodiversity
– Promoted monoculture and tree plantations that are prone to disease or infestation through the lack of diversity.
Bottom Trawling
Uses a funnel-shaped net to drag the ocean bottom. Shrimp, cod, flounder, and scallops. Analogous to clearcutting forests.
bycatch
Species of fish caught but not wanted.
Drift Net
Long expanses of nets that hang down in the water. Traps turtles, seabirds, flounder, and marine mammals.
Long Line
Placing very long lines with thosands of baited hooks. Swordfish, tuna, sharks, halibut, and cod. Endangers sea turtles, pilot whales, and dolphins.
Purse Seine
Surrounds large schools of fish spotted by aircraft with a large net. Met is drawn tight. Tuna, mackerel, anchovies, and herring.
Aquaculture (Mariculture)
Commercial growing of aquatic arganisms for food. It involves stocking, feeding, protection from predators, and harvesting.