HSC 156, Exam 2
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- Be able to describe the things that make soil fertile
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•A root environment with oxygen, proper pH (a mineral) (near neutral), low salt, proper nutrients
•Mineral Nutrients: phosphate, potassium, calcium, and others – no leaching (removal of soluble nutrients) by water percolating through it. This zone of leaching may have a dif appearance and composition from horizons above and below it.
•Water holding capacity
oLow permeability is better because of having thick top soil holds more water; therefore it is better for crops. - Explain how soil texture affect water holding capacity
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oClay, when wet sticky
oSalt- gritty feeling
oSilt – washes down streams. - The best type of soil for growing crops is a combination of what three things and what is the combination called?
- ⬢Loam- a perfect mixture of ingredients: a lot of silt, little clay, and 50% sand
- What are the root causes of erosion?
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Wind and water
Where we abused soil over cultivation, overgrazing, and deforestation - How do you prevent erosion
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•Crop rotations
•No, or low-till agriculture (actually requires the use of herbicides)
•Use of organic fertilizer
•Terrace & contour planting – in way land is shaped, not by rows
•Wind breaks & strip (or alley cropping)
•Protect crops by terracing can help control if hills are steep slopes. - salinization
- too much salt in soil
- water logging
- soil is saturated w/ water & plant roots die from lack of oxygen.
- What are the goals of sustainable agriculture?
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⬢Minimize soil erosion, salinzation & water logging
⬢Grow more perennial crops
⬢Reduce water waste in irrigation
⬢Reduce use & waste of fossil fuels
⬢Increase use of biological pest control & integrated pest management.
⬢Shift to full-cost pricing that includes harmful environmental impacts of agriculture in food prices
⬢Reduce poverty
⬢Slow population growth - What are the benefits of organic verse inorganic fertilizer?
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inorganic- doesnt improve topsoil. It is just putting chemical back into soil where nutrients got lost bc of the crops.
organic- adds humus. dead leaves, compost. - What is Blue Baby Syndrome?
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When babies who drink tap water that is high in nitrates, blood cells cant carry enough oxygen to lungs effectively.
called methemoglobinemia.
Nitrate gets into drinking water from fertilizers and pesticides used in crops. - What is Subsistence Agriculture.
- only producing enough to feed family. farmers of the developing world that use traditional agricultural methods for raising plants, animals, and food.
- Industrialized Agriculture
- What the U.S practices
- Eescribe the world-wide total and per capita production of food over time.
- Population growth averaged 1.7% per year and world wide food production increases an average of 2.2 %
- Describe the environmental costs of agriculture
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~ fossil fuel
~ soil erosion
~ resistant pest varieties
~ groundwater depletion
~ water pollution - The Green Revolution
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Introducting wheat and rice into developing countries because these crops will grow in these countries.
These have greatly increased crop yields. - What is the people-food predicament?
- 64% of US is overweight and there is famine in 3rd world countries. meaning, we have the food but have a problem distributing it.
- 5 nutritional deficiency diseases
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1. Kwashiorkor
2. Marasmus
3. Xerophthalmia
4. Anemia
5. Goiter - Kwashiorkor
- A disease due to the deficiency of lack of or no protein. Affects millions of children in tropical areas, especially Africa.
- Marasmus
- Overal depletion of protein/calories. Not getting enough food. Appearance in children: thin, wasted appearance ; skin hangs in loose wrinkles about wrists and legs ' and eyes are often large and bright becasue of sunken appearance of rest of body
- Xerophtalmia
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~blindness
~ Deficiency of Vitamin A. Associated with protein shortages, because of liver.
Golden rice ~ genetice enginered rice to give it carrot nutrition, so gets Vitamin A. - Anemia
- Deficiency of iron. characterized by lack of energy and low levels of productive activity
- Goiter
- Deficiency of iodine. It is in sald in our country. Affects over 20 million people worldwide. Swollen growth of the thyroid gland
- Prospects for reducing world hunger
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~ Expanding the amount of land under cultivation
~ Increasing world fish catch
~ Reducting post-harvest losses
~ Eating lower on the food chain
~ Improving yields per acre - PEST
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~ Any organism ( animal, plant, or microbe) which adversely affects human interests
~ Not restricted to any one taxonomic group. - 3 problems caused by pests
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1. resource competition - ruin crops
2. Source of discomfort
3. Vectors of disease - living transmitter ex: fleas, body lice, ticks, etc. - Pesticides
- any chemical that kills, controls, drives awa, or modifies the behavior of a pest.
- 7 classes of insecticides
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1.Inorganic- arsenic, sulfur, mercury highly toxic & remain in environment for forever.
2. Natural Organic - chemicals extracted from plants.
3. Fumigans - very small aerosals that are extremely dangerous to works.
4. Chlorinated hydrocarbons (DDT) - stored in fat and persist in the environment.
5. Organicphosphates (OP)- nerve toxins
6. Carbamates - similar to OP but less toxic.
7. Microbial agents and biological controis - living organisms or their toxins that kill pests, e.g. Bacillus thuringenisis (BT) and parasitic wasps. - 3 types of pesticides
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1. Herbicides
2. Insecticides
3. Rodenticides - What is the environmental impact on pesticides?
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⬢Developing resistance
⬢ Killing of beneficial speicies either directly or by food web interruption
⬢ Environmental contamination (groundwater contamination, soil contamination, & threatens species survival) - Describe the hazards to human health from pesticides
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⬢ Not only toxic to pests, but can be toxic to humans
⬢ Pesticides can be taken into the body through the mouth, skin or respiratory system
⬢ Symptoms of acute exposure include headache, weakness, fatigue, or dizziness - The pesticide treadmill
- The development of resistance means that pesticides will never destroy pests completely & this means that larger amounts or more potent pesticides must constantly be used to kill these pests.
- Integraged Pest Management (IPM)
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Aims to minimize the use of synthetic organic pesticides without jeopardizing the environment.
~ Combines 2 or more methods carfully integrated into a total program.
~ Not to eradicate the pests but to manage the pests and to protect the environment. - List alternatives to chemical pest control (5)
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⬢Integrated pest managment (IPM)
⬢ Natural enemies
⬢ Pathogens, & parasites, Bacillus thurengensis (BT)
⬢ Sex attractants (Pheromones)
⬢ Sterile male technique. - Bacillus thuringiensis (BT)
- a bacterium, makes toxins lethal to butterflies and beetles. The genes for some of these toxins have been transferred into crops such as maize and cotton. This allows farmers to reduce insecticide spraying. It is not toxic to humans.
- Socioeconomic issues in pest management
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~ Economic threshold (dont spray until needed)
~ Insurance spraying (don't wait until problem, spray first. Actually increases problem)
~ Cosmetic spraying
~ Export of banned pesticides. - 8 major problems with the US food supply
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1. People sick and die each year
2. New pathogens. Old ones, resistance to treatments because being overused
3. Getting food from all over world
4. Chronic pesticides
5. Issues of new techonlogy. Genetic modified food and reatiating meat and milk, etc.
6. Hormones in milk, using steroids in cows.
7. Food allergies
8. Bio terrorism. - National agencies that are responsible for food protection.
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~FDA
~USDA
~EPA - What is needed to make our food system safer?
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~National Food Safety Initiative with improved outbreak response, better education and increased use of science.
~Single federal angency with responsibility. - Who has the bigger role in food protection, the government or the industry?
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Industry - iperated risk-based system for meat and poultry that is overseen and monitored by the federal government.
~Gov can only be there so often but industry is there every day. - What is foodborne disease?
- Natural toxins in the food. Pesticides or other chemicals. Microbial contamination (bacteria, viruses, parasites, and fungi)
- What are two classes of microbial foodborne disease?
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1. Food infection: caused by harmful organisms that are eaten and multiply in the intestines.
2. food intoxication: caused when the bacteria excrete or give off a poisonous toxin in the food. - Campylobacter
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One of the two common causes of foodborne disease. (although some cases are caused by contaminated water)
~ Causes diarrhea, abdominal pain, fever, nausea, and vomiting.
~symptoms usually last for 2-5 days
~Sources include beef, chicken, and unpasteurized milk - Salmonellosis
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~ The other most common bacterial foodborne disease in the US
~ Associated with eating poultry, meat, or eggs
~Symptoms: abdominal pain, diarrhea, chills, fever, frequent vomiting & prostration. - Listeriosis
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~ Very dangerous to pregnant women & infants.
~ Most often associated with food processing environments & milk products.
~ Refrigeration provides no assurance against bacterial multiplication.
~ Grows vigorously at low temperatures. - Staphylococcus aureus
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~ Violent disease onset.
~ Found in cooked ham, salads of protein food, custard pastries, hollandaise sauce & warned over foods
~ often thought to be the "24 hour flu" - Botulism
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~One of the most serious of all bacterial foodborne diseases.
~Most frequently associated with home-canned, low-acid foods (beans, corn, beets, spinach & mushrooms)
~Is consedered a deadly poison - E. coli
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~commonly associated with raw or rare ground beef, unpasteurized milk, and contaminated water & dirty hands.
~ Highly infectious pathogen in our food supply
~ 200 to 400 very young or elderly ppl. die each year. - Mad-cow disease
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or called BSE is progressive neurological disorder of cows (brain probs)
~Cause is thought to be a prion which is a type of infective protein.
~2 cases in US cattle since 2003.
~ In Great Britain, there have been over 184,000 cases in cattle and there is evidence of this disease in humans. - Steps in preventing foodborne disease
- Avoid cross-contamination, practice good sanitation, avoid the food danger zone, cook and cool foods thoroughly
- Cross contamination
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~transfer of harmful bacteria from one food to another. Can occur by
~~soiled hands
~~soiled utensils or knives
~~kitchen equipment (cutting boards)
~~raw foods to ready to eat foods - Temperature danger zone
- Foods in the range of >40 to <140, in between is the danger zone.
- Cold food temp?
- Below 40 or less
- hot food temp?
- above 140
- Poultry and stuffed foods at or above
- 165
- pork and groun meats at or above
- 155