Food and Agriculture. D.Knauss RRHS 2006

Transcription

1 Food and Agriculture D.Knauss RRHS 2006

2 Nutrition Famine- widespread starvation Malnutrition- condition that occurs when people do not consume enough Calories or do not eat enough variety of foods. Calorie = 1000 calories 1 calorie = amount of energy needed to raise 1 gram of water 1 degree Celsius.

3 Nutrition (continued) Since 1 gram of water = 1 ml of water. 1 Calorie = amount of energy needed to raise the temperature of 1 liter of water 1 degree Celsius Carbohydrates= sugars= energy Examples- potatoes, pasta, sugar, starches,etc Lipids= fats= energy and materials for making membranes and hormones Examples- fatty foods, nuts, oils, etc

4 Nutrition (continued) Proteins= amino acids =used for making enzymes and help maintain metabolism Meat, fruits, and vegetables Amino Acid deficiency- occurs from not getting all of the amino acids necessary to maintain basic metabolism Diet- type and amount of food a person eats

5 Nutrition (continued) Developed countries- tend to eat more food and a larger proportion of proteins and fats than those in developing countries

6 Food Ecology Efficiency- measure of the quantity of food produced on a given area of land with limited inputs of energy and resources Average efficiency of raising livestock is very poor (only 10% of plant energy gets stored in the animals) Meat generally provides more nutrients per gram than most food from plants

7 Food Ecology Yield- the amount of food that can be produced in a given area Researchers looking for organisms that can thrive in various climates with little fertilizer, pesticides, or fresh water.

8 World Food Problems Unequal distribution- food is not spread equally in all areas of the world or even within the same country Droughts and Famines- Drought- prolonged period where the rainfall is below average One year of drought is salvageable but after several years the soil will be unusable due to loss of microbes

9 Green Revolution Production of food crops rose dramatically in Mexico and India due to new crop varieties and new agricultural technologies Negative effects- crops required high amounts of fertilizers, water, and pesticides Subsistence farmers- (farmers who grow food only for local use) unable to afford the new seed and technologies

10 Farming Arable land- land that can be used to grow crops Farming Plowing Fertilization Irrigation Pest control Harvesting

11 Farming Plowing is also referred to as Tilling (Roto-tiller) Plows- pulled by tractor, livestock, or the farmer themselves Mixes soil nutrients, loosens soil for planting, uproots weeds Irrigation- water flowing through ditches, sprayers, also involves tiling fields for drainage

12 Farming Fertilizing- manure for most organic farms mixed with crop rotation. Nitrogen fertilizers are often used on all farms regardless Pest control- both animal and plant pests are addressed through spraying or by biological methods(insect predators). Harvesting- done by hand or by machine

13 Soil Profiles Plants depend on soil for nutrients, stability, and moisture. Knowing about the soil profile can help the farmer determine what they can do to ensure a good crop from one year to the next.

14 Soil Erosion Almost all farming methods increase soil erosion Land degradation- human activity or natural processes damage the land so that it can no longer support the natural ecosystem Desertification- process by which land in arid or semiarid areas becomes more desert-like because of human activities

15 Soil Erosion Desertification- (continued) Areas affected by desertification include the Great Plains, the Sahel region in Africa, etc.

16 Soil Conservation Practices Fallow- leaving the land unplanted for several years to regain its fertility Contour plowing- farmer plows rows across the hill to hinder soil erosion downslope

17 Soil Conservation Practices Terracing- farmer builds step-like areas where crops can grow (best with valuable crops like grapes and coffee)

18 Soil Conservation Practices No-till farming- crops are harvested and planted without tilling of the soil. Advantage- less soil erosion and less time is needed to prepare for next crop Disadvantage- soil compaction reduces plant productivity over time

19 Soil Enrichment Practices Fertilizers- Organic- leaves and manure Inorganic- chemical fertilizers applied by using sprays, pellets, or direct injection into the soil (Nitrogen) Most farmers use a blend of both Compost- partly decomposed organic material

20 Compost Bin

21 Salinization Accumulation of salts in the soil. Major problem in California and Arizona where the soil is naturally salty to begin with. Salts accumulate until no plants can grow

22 Pest Control Insects in North America eat about 13% of all crops Insects across the world destroy about 33% of the world s potential food harvest Crop plants have no built-in defenses against pests like wild plants do. Wild plants also have predators that live in or on the plant

23 Pesticides Chemicals used to kill insects, and other crop pests. These chemicals can also harm beneficial plants, insects, wildlife, and people Pesticide resistance- ability of an insect to survive a particular pesticide.

24 Pesticides Pest organisms typically have high reproduction rates which allows for more genetic variation. This means that some members of the population may evolve a resistance to the pesticide Human health concerns- Children who live in these areas sometimes have cancer rates higher than the national average

25 Pesticides Persistent Pesticides- does not break down quickly or easily in the environment Results in these compounds accumulating in the soil and water systems for days to decades to forever DDT used in the 1970 s is still detectable in women s breast milk

26 Pest Management Biological Pest Control- use of living organisms to control pests Pathogens- organisms that cause disease Plant Defenses- farmers select varieties of plants that contain specific defenses against pests (tougher skin, chemical compounds, etc)

27 Pest Management Chemicals from Plants- use a plant s natural defense mechanism as a pesticide for other plants Advantage is that they are more biodegradable Disrupting Insect Breeding- Growth regulators- interfere with some stage of a pest s life cycle Pheromones- sex hormones that attract males to areas where females are not

28 Pest Management Disrupting Insect Breeding- (continued) Irradiate males so that they cannot produce viable sperm. Females then lay unfertilized eggs Integrated pest management- idea is to reduce pest damage to a level that is economically acceptable

29 Pest Management Genetic Engineering- technology in which genetic material is modified for medical or industrial use (GM = genetically modified) Problems- may cause problems if GM plants are allowed to breed with wild species

30 Sustainable Agriculture Farming that conserves natural resources and helps keep the land productive indefinitely Also referred to as low-input farming

31 Animals and Agriculture Approximately 50 animal species have been bred and managed for human usedomesticated Overharvesting- catching or removing from a population more organisms than the population can replace Fishing Important for the continuation of the species and for businesses to survive

32 Animals and Agriculture Aquaculture- raising of aquatic organisms for human use or consumption China is the world leader in this area Fish Farms- raised in individual ponds until mature enough to harvest Ranch- young are raised and then are released into the wild. Adults are harvested when they come back to spawn

33 Environmental Damage from Aquaculture Large amounts of waste Local water supplies can be depleted Damage nearby wetland areas

34 Livestock Domesticated animals raised to be used on a farm or ranch or to be sold for profit Provide the following: Meat - Leather - Wool Eggs - Draft Animals - Manure Ruminants- cud-chewing mammals that have 3- to 4-chambered stomachs Cud- food that the animals regurgitate from their first stomach to chew again

35 Livestock Cattle can be used for: Milk Blood Meat Dung Chickens- numbers have increased by a greater percentage than any other livestock

36 Livestock Poultry- domesticated birds raised for meat and eggs Ducks and Geese- not used as often as a food source but in certain areas fulfill other important roles Fertilizer Watch dog

37 Livestock Environmental Problems- HUGE environmental problems occur due to the waste products from livestock farms. High nitrogen fertilizer kills fish in streams and also can be toxic waste depending on what the birds are fed Avian flu is also a huge health problem across the world at this time