Food and Agriculture

1
Food and Agriculture
2
Outline

• Food and Nutrition
• Key Food Sources
• Soil
• Structure
• Erosion
• Agricultural Resources
• Water
• Energy
• Genetic Engineering
• Sustainable Agriculture

3
FOOD AND NUTRITION

• World food supplies have more than kept up with
  human population growth over the past two
  centuries.
• During the past 40 years, population growth has
  averaged 1.7 per year, while food production
  increased an average 2.2.

4
Chronic Hunger and Food Security

• In 1960, 60 population of developing countries
  were considered chronically undernourished.
• Fallen to less than 15.
• Poverty is the greatest threat to food security
  (Ability to obtain sufficient food on a daily
  basis).
• Operates on multiple levels.
• Recognizing role of women in food production is
  an important step forward.

5
Risk of Inadequate Nutrition
6
Acute Food Shortages

• Famines are characterized by large-scale food
  shortages, massive starvation, social disruption,
  and economic chaos.
• Mass migrations often occur because productive
  capacity has been sacrificed.
• Environmental conditions are immediate trigger,
  but politics and economics are often underlying
  problems.
• Arbitrary political boundaries block historic
  access to refuge areas.

7
Famines

• Aid policies of rich countries often serve to
  distribute surplus commodities and produce
  feeling of generosity.
• Food camps have serious drawbacks
• Stress and crowding.
• Lack of sanitation.
• Close contact to epidemic diseases.

8
Malnutrition and Obesity

• Malnourishment - Nutritional imbalance caused by
  a lack of specific dietary components.
• In poorer countries, people often cannot afford
  to purchase an adequate variety of foods,
  including meats and vegetables.

9
Obesity

• The most common dietary problem in wealthy
  countries is over-nutrition.
• According to U.S. Surgeon General
• 62 of Americans are overweight.
• 33 are obese.

10
Nutritional Problems

• Iron deficiency is the most common dietary
  imbalance in the world.
• Leads to anemia.
• Increases risk of death from hemorrhage in
  childbirth and affects development.
• Red meat, eggs, legumes, and green vegetables are
  all good sources of iron.

11
Protein Deficiency Diseases

• Kwashiorkor - Displaced Child - Occurs mainly
  in children whose diet lacks high-quality
  protein.
• Reddish-orange hair, bloated stomach.
• Marasmus - To Waste Away - Caused by a diet low
  in protein and calories.
• Very thin, shriveled.

12
KEY FOOD SOURCES

• Three crops deliver majority of worlds
  nutrients
• Wheat, Rice and Corn
• Potatoes, barley, oats and rye are staples in
  cool, moist climates.
• Cassava, sweet potatoes, and other roots and
  tubers are staples in warm wet climates.

13
Meat and Dairy

• Distribution highly inequitable.
• More developed countries make up 20 of world
  population, but consume 80 of meat and dairy
  production.
• 60 of production occurs in lesser developed
  countries.
• 90 of grain grown in NA is used to feed
  livestock.
• FAO claims using cereals as animal feed does not
  contribute to hunger and undernutrition.

14
Seafood

• Seafood is an important protein source.
• Since 1989, 13/17 major fisheries have declined
  or become commercially unsustainable.
• FAO estimates operating costs for the 4 million
  boats now harvesting wild fish exceed fish sales
  by 50 billion annually.
• Aquaculture is providing an increasing share of
  the worlds seafood.

15
FARM POLICY

• Farm subsidies in many countries are protected by
  powerful political and economic interests.
• Agricultural subsidies encourage surpluses and
  allow American farmers to sell products overseas
  at prices below production costs.

16
SOIL A RENEWABLE RESOURCE

• Soil - A complex mixture of weathered minerals,
  partially decomposed organic materials, and a
  host of living organisms.
• At least 15,000 different soil types in the US.
• Vary due to influences of parent material, time,
  topography, climate, and organisms.
• Can be replenished and renewed.

17
Soil Composition

• Particle size affects soil characteristics.
• Spaces between sand particles give sandy soil
  good drainage and allow aeration.
• Can easily dry out.
• Tight packing of small particles in silty or clay
  soils makes them less permeable to air and water.

18
Soil Composition

• Soil exhibits wide range of organic content.
• Humus - Insoluble residue from partially
  decomposed plants and animals.
• Most significant factor in soil structure.
• Activity of organisms living in soil helps create
  structure, fertility, and cultivation suitability.

19
Soil Organisms

• Activity of organisms living in the soil help
  create structure, fertility, and tilth.
• Micorrhizal symbiosis between plants roots and
  specific fungal species.

20
Soil Profiles

• Soils are stratified into horizontal layers
  called soil horizons.
• Together make up soil profile.
• O Horizon (Organic layer)
• Leaf litter, partially decomposed organisms.
• A Horizon (Topsoil)
• Mineral particles mixed with organic material.

21
Soil Profiles

• E Horizon (Leached)
• Depleted of soluble nutrients.
• B Horizon (Subsoil)
• Often dense texture from accumulating nutrients.
• C Horizon (Parent Material)
• Weathered rock fragments with little organic
  material.

22
(No Transcript)
23
Soil Types

• Soils are classified according to structure and
  composition (12 Orders)
• Mollisols Andisols
• Alfisols Vertisols
• Spodosols Histosols
• Oxisols Inceptisols
• Ultisols Entisols
• Aridosols Gelisols

24
WAYS WE USE AND ABUSE SOILS

• Approximately 11 of the earths land area is
  currently in agricultural production.
• Up to four times as much could potentially be
  converted to agricultural use.
• Much of this additional land suffers from
  constraints.

25
Land Resources

• In developed countries, 95 of recent
  agricultural growth has been from altered
  agricultural practices (pesticides - fertilizer).
• Less land cultivated in NA now than 100 years
  ago.
• Many developing countries are reaching limit of
  lands that can be exploited for agriculture
  without unacceptable social and environmental
  costs.

26
Land Degradation

• Estimated nearly 3 million ha of cropland ruined
  annually via erosion, 4 million ha transformed
  into deserts, and 8 million ha converted to
  non-agricultural uses.

27
Land Degradation

• Definitions of degradation are based on both
  biological productivity and expectations of what
  land should be like.
• Generally, land is considered degraded when soil
  is impoverished or eroded, run-off is
  contaminated, or biodiversity is diminished.
• Water and wind are the driving forces for vast
  majority of soil degradation.

28
Global Soil Degradation
29
Erosion

• Erosion is an important natural process,
  resulting in redistribution of the products of
  geologic weathering, and is part of both soil
  formation and soil loss.
• Tends to begin subtly.
• Worldwide, erosion reduces crop production by
  equivalent of 1 of world cropland per year.

30
Mechanisms of Erosion

• Sheet Erosion - Thin layer of surface removed.
• Rill Erosion - Small rivulets of running water
  gather together and cut small channels.
• Gully Erosion - Rills enlarge to form bigger
  channels too large to be removed by normal
  tillage.
• Streambank Erosion - Washing away of soil from
  established streambanks.

31
Mechanisms of Erosion

• Wind can equal or exceed water as an erosive
  force, especially in a dry climate and on flat
  land.
• Intensive farming practices
• Row crops leave soil exposed.
• Weed free-fields.
• Removal of windbreaks.
• No crop-rotation or resting periods.
• Continued monocultures.

32
OTHER AGRICULTURAL RESOURCES

• Water
• Agriculture accounts for largest single share of
  global water use.
• As much as 80 of water withdrawn for irrigation
  never reaches intended destination.
• Cheap cost encourages over-use.
• Waterlogging
• Salinization

33
Fertilizer

• Lack of nitrogen, potassium, and phosphorus often
  limits plant growth.
• Adding nutrients via fertilizer usually
  stimulates growth and increases crop yields.
• 1950 - Average of 20 kg/ha fertilizer used.
• 1990 - Average of 91 kg/ha fertilizer used.
• Manure and nitrogen-fixing bacteria are
  alternative methods of replenishing soil
  nutrients.

34
Energy

• Farming in industrialized countries is highly
  energy-intensive.
• Between 1920-1980, energy use rose directly with
  mechanization of agriculture, and indirectly with
  spraying of chemicals.
• Altogether, US food system consumes 16 of total
  energy use.
• Most foods require more energy to produce,
  process, and transport than we yield from them.

35
NEW CROPS AND GENETIC ENGINEERING

• Most of world food comes from 16 widely grown
  crops.
• At least 3,000 species of plants have been used
  for food at some point in time.
• Many new or unconventional varieties might be
  valuable food supplies.
• Winged-bean
• Triscale

36
Green Revolution

• Most major improvements in farm production have
  come from technological advances and modification
  of a few well-known species.
• Corn yields jumped from 25 bushels per acre to
  130 per acre in last century.
• Most of gain accomplished through conventional
  plant breeding.
• Also seen rise of dwarf varieties.
• Green Revolution - Spread of new varieties around
  the world.

37
Genetic Engineering

• Genetically Modified Organisms (GMOs)
• Contain DNA possessing genes borrowed from
  unrelated species.
• Can produce crops with pest-resistance and wider
  tolerance levels.
• Opponents fear traits could spread to wild
  varieties, and increased expense would largely
  hurt smaller farmers.
• Estimated that 60 of all processed foods in NA
  contain transgenic products.

38
Pest Resistance and Weed Control

• Biotechnologists have recently created plants
  containing genes for endogenous insecticides.
• Concern has arisen over several points.
• Spread of genes into wild populations leading to
  resistance in pests.
• Effect on nontarget species.

39
Is Genetic Engineering Safe ?

• Environmental and consumer groups have campaigned
  against transgenic organisms.
• Frankenfoods
• U.S. Food and Drug Administration declined to
  require labeling of foods containing GMOs.
• New varieties are substantially equivalent to
  related traditionally-bred varieties.

40
SUSTAINABLE AGRICULTURE

• Soil Conservation
• Managing Topography
• Contour Plowing - Plowing across slope to slow
  flow of water.
• Strip Farming - Planting different crops in
  alternating strips along land contours.
• Terracing - Shaping land to create level shelves
  of earth to hold water and soil.
• Plant perennial species.

41
Sustainable Agriculture
42
Soil Conservation

• Providing Ground Cover
• Annual row crops cause highest rates of erosion
  because they leave soil bare for much of the
  year.
• Leave crop residue after harvest.
• Plant cover crops after harvest.

43
Soil Conservation

• Reduced Tillage
• Minimum Till - Chisel plow
• Conserv-Till - Coulter (Disc)
• No-Till - Drilling
• Often farmers using conservation tillage must
  depend relatively heavily on pesticides.
• Traditional tillage helped control weeds and
  pests.

44
Low-Input Sustainable Agriculture

• Do not depend on chemical fertilizers and
  pesticides, and use antibiotics only to combat
  illness.
• Typically do not produce as high quality product
  as intensive farmers, but production costs are
  lower, and often obtain higher prices.

45
Summary

• Food and Nutrition
• Key Food Sources
• Soil
• Structure
• Erosion
• Agricultural Resources
• Water
• Energy
• Genetic Engineering
• Sustainable Agriculture

46
(No Transcript)