Foods

1. Foods Can we continue to feed the world?

2. Human Nutrition • Calories = measure of energy in food • Need approx. 2,000 per day • People who eat less calories than they burn are undernourished (marasmus) • Nutrients = proteins, lipids, carbohydrates, vitamins, and minerals • Need specific amounts of specific nutrients • People who do not ingest the required nutrients are malnourished (kwashiorkor is lack of protein)

3. World Hunger • Enough grain is grown to feed the world population • Grain is fed to livestock • Food is not distributed to people who need it • Poverty, transportation, conflict

4. The Green Revolution • Traditional Agriculture • Planting and harvesting done by human labor • Industrialized Agriculture • Planting and harvesting done by machines (uniformity!) • Began in the late 1800’s • The Green Revolution • New breeds of seeds, new pesticides, new irrigation all led to higher yield • Began in the 1950’s

5. Soil • Soil Components • Weathered rocks minerals • Organic matter and nutrients • Air space, water, and organisms • Soil Layers • O, A, E, B, C • Soil Types • Clay • Silt • Sand • Loam

6. Erosion & Land Degradation • Erosion • Increased by farming • Desertification • Monoculture strips nutrients • Overgrazing compacts soil, kills vegetation • Too much irrigation leads to water shortage • Land becomes less productive • Salinization • Too much irrigation increases salt content due to evaporation

7. Soil Conservation • No-till farming • Reduce erosion by covering exposed soil • Contour Plowing • Plant crops perpendicular to slope of hill • Strip-cropping and agro-forestry • Alternate rows of cover crops or trees

8. Fertilizers and Compost • Inorganic (synthetic) fertilizers • Monoculture farming strip nutrients from soil • Synthetic fertilizers are inexpensive solution • Runoff can pollute waterways (algal blooms) • Compost • Decomposed plant materials • Less pollution problems • (difficult large scale)

9. Pests and Pesticides • Pests damage crops • Insects, plants, fungi, microorganisms • Monocultures make farms vulnerable to pests • Pesticides kill pests • Began with naturally occurring compounds (ex: arsenic) • Organic chemical pesticides introduced Post WWII

10. Problems with Pesticides • Pesticide Resistance • Resistant pests survive spraying and reproduce • Human health concerns • Ingestion of pesticides on fruits and vegetables • Hazards to workers and local area (manufacturing) • Bioaccumulation • Toxins concentrate at top of food chain

11. Alternatives to Pesticides • Integrated Pest Management • Control population to prevent economic loss • Biological Control • Predators who eat pests (ex. Ladybugs eat aphids) • Pathogens that attack pests (ex. Bt) • Naturally-derived plant chemicals • Plants bred for better defenses • Insect pheromone traps or growth regulators

12. Genetic Engineering • Benefits • Grow more food in more places (tolerances) • Pesticide resistance and pesticide crops (Bt) • Drawbacks • Potential allergic reactions • Development of “Super-weeds” • Loss of genetic diversity • Patenting vs. rights of farmers

13. Fish: Overharvesting • Overharvesting: • Efficient gear increased landings beyond M.S.Y. (Maximum Sustainable Yield) • Effects on the ecosystem • Habitat destruction, ecosystem impacts, recruitment loss (catch fish before they reproduce) • By-catch: what you’re NOT trying to catch • Sea turtles, marine mammals, fish that are too small • Management plans • Size limits, gear restrictions (TED’s), licensing

14. Fish: Aquaculture • Grow fish in ponds or nets • prevent depletion of wild stocks • Problems: • Destruction of coastal ecosystems • Escapees (invasive species) • Feeding aquaculture fish with wild-caught fish

15. Livestock • Concentrated Animal Feeding Operations (CFO’s) • Fed corn and other scraps (no grazing or foraging) • Confined spaces create unhealthy conditions: require use of antibiotics • Manure is health/safety and waste problem