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Food & Agriculture. Chapters 11 & 12 APES 2008. 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

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food agriculture

Food & Agriculture

Chapters 11 & 12



is there enough food
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.
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.
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.
  • 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)
  • 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
major crops
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)
meat milk poultry
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!
meat vs grain
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.
fish seafood
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
importance of soil
Importance of Soil
  • Important resource for growing crops!
  • An ecosystem (See Ch. 12 page 219-222)
what nutrients are important in soil
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.
what nutrients are important in soil1
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.
what nutrients are important in soil2
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)

why should we know about soil ph
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
what do those numbers mean on a bag of fertilizer
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
new crops
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?)
green revolution
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.
gene revolution
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
pest resistance
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
weed control
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”
sustainable agriculture
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.