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 14%.
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. Hunger Around the World

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 world’s 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.
More than 1/3 of the total maize, soy, and coarse grain production are used as livestock feed.
However, 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 world’s 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.

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 12.5% of the earth’s 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. Desertification
Conversion of productive lands to desert
threatens 1/3 of the earth’s surface
Rangelands and pastures are highly susceptible (overgrazing, soil degradation)
Africa and China are of particular concern
rapid population growth and poverty create unsustainable pressures

33. Desertification

34. 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

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

36. Energy
Farming in industrialized countries is highly energy-intensive.
Between , 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.

37. 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

38. 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.

39. Genetic Engineering
Genetically Modified Organisms (GMO’s)
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.

40. 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.

41. 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 GMO’s.
New varieties are “substantially equivalent” to related traditionally-bred varieties.

42. 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.

43. Sustainable Agriculture

44. 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.

45. 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.

46. 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.

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