1. Food and Agriculture

4. History and Types of Agriculture
Demand-based agriculture - production determined by economic demand and limited by classical economic supply and demand theory. This approach became common during the industrial revolution.
Resource-based agriculture - production determined by resource availability; economic demand usually exceeds production. This approach was the original type of farming 10,000 years ago. Modern approaches are very high tech and somewhat more expensive.

5. Plant Food Sources 250,000 plant species Þ 3000 tried as crops Þ
300 grown for food Þ
100 species used on large scale for food Þ
15 to 20 species provide vast majority (90%) of man’s food needs
It takes about 16 pounds of grain to produce one pound of edible meat
Largest crop volumes provided by: wheat, rice, corn, potatoes, barley
Wheat and rice supply ~60% of human caloric intake

6. Other Plant Food Sources
Potatoes
Barley
Sweet Potato
Cassava (source of tapioca)
Grape
Soybean
Oats
Sorghum
Sugarcane
Peanut
Watermelon
Cabbage
Onion
Bean
Pea
Sunflower Seed
Mango
Millet
Banana
Tomato
Sugar Beet
Rye
Orange
Coconut
Cottonseed
Apple
Yam

7. Types of Crops Cash crops vs. subsistence crops
cash crops may provide non-food products (latex)
provide products which do not make up our primary nutrition (tea, coffee)

8. Agroecosystems Ecosystem created by agricultural practices
characterized by low
Genetic diversity
Species diversity
Habitat diversity

9. Agroecosystems
Agroecosystems differ from natural ecosystems in five major ways:
Farming attempts to stop ecological succession
Species diversity is low
farmers usually practice monoculture
monoculture tends to ß soil fertility
Farmers plant species (crops) in an orderly fashion - this can make pest control more difficult
Food chains are far more simple in agroecosystems
Plowing is like no other natural disturbance
plowing can Ý erosion
cause more nutrient loss (which is replaced by fertilizer)

10. World Food Supply and the Environment
Our current food problem is the result of our human population
Food production depends upon favorable environmental conditions
Agriculture changes the environment - such changes can be detrimental
Food supply can be adversely affected by social unrest that influence agriculture

11. Grain Production
Grain production increased from 631 to 1780 million metric tons from 1950 to 1990.
Has leveled off since then
Top five countries in order of producing the most amount of grain are:
China
United States
India
Canada
Ukraine

16. Livestock
· domesticated livestock (sheep, pigs, chickens, cattle) are an important food source for humans
· ruminants (four-chambered stomachs) contain bacteria that can convert plant tissue to animal protein/fat Þ hence, plant material originally unusable for man is converted into food sources that can be ingested by man

17. Wilkes, Angela. My first word board book. (1999) DK Publishing, NY.

18. Meat Sources
About 90% of all meat and milk are consumed by United States, Europe and Japan which constitute only 20% of world population
About 90% of the grain grown in the United States is used for animal feed
16 kg of grain Þ 1 kg of meat
By eating grain instead would get 20 times the calories and 8 times the protein

19. Malnutrition and Famines
One quarter of the human population is malnourished
Sub-Saharan Africa (~225 million)
East and Southeast Asia (~275 million)
South Asia (~250 million)
Parts of Latin America

21. Malnutrition/Famines
Stem from not enough calories per day in addition to not getting the necessary amounts of carbohydrates, proteins, lipids (fats), minerals, and vitamins
Generally diets are high in starches
Famine conditions
Major droughts -- Political instability
Population sizes -- Land Seizures
Massive immigration -- Pestilence
Floods Distribution breakdown
Wars --Panic buying
Chaos in economy -- Hoarding

22. Limits on Food Production
· arable land
· precipitation
· temperature
· global warming (ice age temp was only 5o C less than now!)

23. Methods to Increase Food Supply
Improved irrigation and utilization of water
Drip irrigation
Increasing arable land
Difficult because of precipitation and temperature
Eating lower on the food chain
Most rangeland is not arable and humans cannot utilize grass/hay as food; therefore, this argument is not considered valid

24. Methods to Increase Food Supply
Food distribution modification
Today distribution of food is a major problem in Africa/Asia
Best solution: teach locals how to best utilize their land with appropriate technology so they can attempt to support themselves and not rely on others.

26. New vs. Old
Agriculture

27. Soil Resources
What is Soil?
Ways We Use and Abuse Soil
Erosion 12

33. How much Land is Arable?

41. Pests and Pesticides

47. The problem with chemicals
Groundwater contamination
Effects of low concentrations?
Bioaccumulation and Biomagnification

50. Pesticides Pro and Con
Kill unwanted pests that carry disease (rats, mosquitoes, Tse-Tse flies)
Increase food supplies
More food means food is less expensive
Effective and fast-acting
Newer pesticides are safer, more specific
Reduces labor costs on farms
Food looks better
Agriculture is more profitable
Accumulate in food chain
Pests develop resistance – 500 species so far
Resistance creates pesticide treadmill
Estimates are $5-10 in damage done for $1 spent on pesticide
Pesticide runoff
Destroy bees - $200 million
Threaten endangered species
Affect egg shell of birds
5% actually reach pest
~20,000 human deaths/year

51. Types of Pesticides Biological – Ladybugs, parasitic wasps, etc.
Carbamates effect nervous system of pests more water soluble than chlorinated hydrocarbons
Aldicarb, aminocarb, carbaryl (Sevin), carbofuran, Mirex
Chlorinated Hydrocarbons affect nervous system –
Aldrin, Chlordane, DDT, dieldrin, lindane and paradichlorobenzene
Fumigants are used to sterilize soil and prevent grain infestation

52. Types of Pesticides Inorganic – arsenic, copper, lead, mercury
Highly toxic and bioaccumulation
Organic or natural – derived from plants such as tobacco and chrysanthemum
Organophosphates – extremely toxic, low persistence
Malathion, parthion, chlophyrifos, acepate, propetamphos and trichlofon

53. Integrated Pest Management
Some practices for preventing pest damage may include
inspecting crops and monitoring crops for damage
using mechanical trapping devices
natural predators (e.g., insects that eat other insects)
insect growth regulators
mating disruption substances (pheromones)
if necessary, chemical pesticides

54. Parts of IPM Polyculture instead of monoculture
Intercropping – alternate rows of crops that have different pests
Planting pest-repellent crops
Mulch to control weeds
Natural insect predators – ladybugs, preying mantis, birds
Rotating crops to disrupt insect cycles
Using Pheromones to attract insects to traps
Releasing sterilized insects