Food & Agriculture

1. Food & Agriculture Chapters 11 & 12 APES 2008

2. Is there enough food? • As population has increased, our food supply has increased. • There is enough food for everyone but it is not distributed equally. • We in US are overnourished- consume too many calories • Some countries have overcome food shortfalls • EX: Indonesia used to largest importer of rice, now they are the biggest producers of rice. • Why? irrigation, fertilizers, pesticides, use high yielding crop varieties of rice. • Other countries are still undernourished (don’t get enough calories) • Sub-Saharan Africa- drought, war, governmental mismanagement have kept people starving in poverty.

3. In developing countries, 800 million people are chronically hungry. 200 million of them are kids • Undernourishment during childhood results in • Stunted growth • Mental retardation • Social/developmental disorders • Undernourished more susceptible to infectious disease & diarrhea.

4. Poverty is the greatest threat to food security- ability to get food everyday. • 1.4 billion that live on $1/day can’t buy food or have no means to grow it for themselves. • In many families the males get largest & most nutritious share- females & kids have poorest diet.

5. Malnourishment • Not only need calories, but also specific nutrients • Malnourished- lack of necessary nutrients (protein, vitamins, minerals) • Kwashiorkor- protein deficiency but has enuf calories; reddish/orange hair, discolored skin, swollen belly, susceptible to infectious disease • Marasmus- diet low in calories & protein; thin, shriveled, susceptible to infectious disease • Most countries eat maize (corn), rice, manioc (tapioca) but these food lack essential vitamins like… • Folic acid (for fetal brain development) • Vitamin A (for good vision) • Iron (for strong blood) • Iodine (for making of thyroxine- which regulates metabolism & brain fxn)

6. Famine • Large-scale food shortages, massive starvation, social disruption, economic chaos • Usually mass migrations to refugee camps in search of food & medical care • Can be caused by… • Environmental conditions- drought, insect infestations • Politics & War- political boundaries can prevent people from following traditional routes to flee environmental disaster

7. What you need to be healthy…

8. Major Crops • Wheat & rice are staple foods for 5 billion people in developing countries. • In mountainous areas- potatoes, barley, oats & rye (N. Europe, N. Asia) • In warm, wet areas- cassava, sweet potatoes, roots/tubers (Amazonia, Africa) • In dry regions- Millet & sorghum (Africa)

9. Meat, Milk, Poultry • N. America, Europe, Japan make up 20% of world population. We consume 80% of milk & meat. • LDC have 80% of population, raise 60% of meat, but consume only 20% of that meat. Most is exported. • 90% of N. American grain is used to feed livestock. What a waste of energy!

10. Meat vs. Grain • Every 16 kg of grain fed to cows produces 1 kg of edible meat. • The other 15 kg are used by the animal for energy. • If we ate grain directly, we would get 21x more calories & 8x more protein than by eating the meat it produced.

11. Fish & Seafood • Important source of protein in many countries • Oceans & major rivers are overharvested or habitats are destroyed • Radar, sonar, remote sensing, GPS, longlines with 60,000 hooks, trawl nets large enough to engulf a jumbo jet, make it possible to exhaust entire populations in just a few years. • 1 in 4 animals caught in nets are “by-catch” or non-target animals (diving birds, marine mammals) • According to UN, 70% of world’s edible ocean fish, crustaceans, & mollusks are declining & in urgent need of managed conservation. • Aquaculture- controlled fish farming- is becoming more popular

12. Importance of Soil • Important resource for growing crops! • An ecosystem (See Ch. 12 page 219-222)

13. What nutrients are important in soil? 1. Nitrogen- (N) • Need for making chlorophyll for leaves • Rapid plant growth and healthy leaves. • Important for leafy veggies- spinach, lettuce, cabbage, soybeans, corn • Deficiency results in yellow or reddish leaves.

14. What nutrients are important in soil? 2. Phosphorus- (P) • Needed for root development & growth. • Helps produce flowers & fruit • Deficiency results in darkening of leaves then reddish tinge around edges. • Important for beets, potatoes, carrots, & radishes.

15. What nutrients are important in soil? 3. Potassium- (K) • Also called potash • Deficiency results in puckering & yellow-brown leaves. • Needed for • Rapid cell growth at root tips • Resistance to disease • Makes stems strong Important for potatos, beets, carrots, radishes, bud crops (asparagus, broccoli, cauliflower)

16. Why should we know about soil pH? • pH of soil can affect how plants absorb N, P, K • Most plants like neutral to slightly acidic soil (6.0-6.8) • Some carnivorous plants like more acidic(4.0-5.0) • To adjust soil pH… • Add lime to make more basic • Add alum to make more acidic

17. What do those numbers mean on a bag of fertilizer? • Indicates % of N, P, K in the fertilizer • Different plants have different nutrient needs. • Pros of commercial fertilizer: • Greatly increases crop yield • Greatly increase crop quality • Cons of commercial fertilizer: • Pollute & degrade soil • Cause eutrophication

18. New Crops • We have used around 3,000 different crops as food source but now currently use about 16 different species. • Some New Crops… • Winged beans- completely edible, resistant to disease, enrich soil, like warm climate • Tricale- cross betwn wheat & rye, likes light, sandy infertile soil, drought resistant, tested for growth in salty soil (might be able to irrigate with ocean water?)

19. Green Revolution • About 50 years ago, new strains of high yielding wheat & rice were developed through cross pollination • If given optimum levels of fertilizer, water, protection from pests these will yield lots of product. • Poor farmers however, cannot afford the fertilizers, seeds, equipment, etc so did not help out in LDC.

20. Gene Revolution • Genetic engineering- altering genes by splicing genes of desirable traits & inserting into food crop. • Potential for • Engineering crops to withstand salty, waterlogged, or low nutrient soil • “grown-in” pesticides so no spraying • Make food more nutritious • 1/3 of all corn & soybean is transgenic; 1/5 of all cotton • 70% of all processed food is made with transgenic material

21. Pest Resistance • Bacillus thuringiensis (Bt)- bacterium that is lethal to butterflies & beetles. • Bt was transgenically inserted in potatoes, cotton, & corn. Bt gives off poison all growing season not just when needed. • Now scientists worried this is creating “superbugs” or Bt-resistant pests. • By planting non-Bt crops with Bt crops allows some pests to “hide-out” and munch (keeping them “wild”, while others die.) By breeding “wild-type” and Bt exposed, may dilute recessive resistance gene. • Negatives- can kill “non-target” organisms (Monarch butterflies) if pollen moved by air to milkweed plant

22. Weed Control • Making plants with herbicide resistant genes means you can spray heavy doses of herbicide and kill weeds but not crop. • Pros- don’t have to till so can leave crops to fall over & prevent soil erosion • Cons- may create “super-weeds”

23. Sustainable Agriculture Soil Conservation important in maintaining arable land. • Land management- terracing, strip farming, contour plowing help prevent water & wind erosion • Using cover crops (rye, alfalfa) after harvest prevents erosion & returns N to soil. Also use mulch. • Use reduced tillage system • Minimal till • Conserv-till • No- till planting- best; keeps all cover plant in place and pushes crop seed into soil • Cons of these systems- must use more herbicide to keep weeds low.