Agriculture - Download as PowerPoint by LekqG4



Most important question of the day: What’s for lunch?
          Agriculture: deliberate land modification through plant
             cultivation and raising animals for food or profit.

• Percentage of labor force MDC:
  5% (avg.), LDC: 55%
Source URL:
                              Subsistence Agriculture:

             food production primary for farm family consumption
                          Example: slash and burn
                                    Commercial Agriculture:

• food production primarily for sale off the farm
• Can Start as subsistence farming, excess sold
• Can transition to pure commercial agriculture


    integration of commercial agriculture into food processing,
                      usually by corporations
Image: http://www.agribusiness-
                                    Wet Rice Agriculture
                                                                   Subsistence     Cash Crop
                                                                 Flooding, pests, (Same)
                                                                 drought, wind,
                                                                 Lower yield     Higher yield
                                                                 No / low debt   Need inputs
                                                                                 Higher debt
                                                                 Low profit      Profits 
                                                                                 inputs, savings
                                                                                 for lean years
• Generally expands to hillsides as population increases
• In earthquake zones, mudslide risks increase… Also, storms.
•   Image:
•   Information:
Swidden Agriculture / slash and burn / shifting cultivation
1.         Slash vegetation.
2.         Burn the slashed veg.
3.         Plant in nutrient ashes.
4.         Yields drop off.
5.         Change sites. Repeat.

          Requires much land
           recovering from past
           slash and burn
           Shifting cultivation (observations)
•   SOUND: Done wisely, it is
    ecologically sound in
    otherwise uncultivable soils.
•   POPULATION: Increasing
    population density eventually
    makes this practice
•   TITLE: In some countries,
    land tenure (ownership) is
    established by cutting the
    land, not leaving it “idle”
    (letting it recover).
•   COMPETITION: In some
    places, shifting cultivation is
    being replaced by a pattern
    of logging, cattle ranching,
    and more intensive cash crop
•   LOSS: This can be a first
    step in forest conversion to

            Issues for subsistence agriculture:
•   Population growth
    – Forest fallow  bush fallow  short fallow  annual  multi-cropping
        • Intensification may not be sustainable. (Site dependent)
    – New farming methods require cash.
        • more inputs: fertilizer, manure, new tools, more labor intensive
        • new seeds and new crops
        • Needs to have enough income to fertilize, buy equipment, buy seed.
•   International trade pressure:
    – conversion of food crops to cash crops for more profit…
    – drug crops (can be involuntary)
       Intensive subsistence agriculture:

Examples: wet rice cultivation, dry farming
•   maximize yield per acre, minimize unused land, some
    double cropping
•   low machinery inputs, high animal and human inputs
•   dry farming  crop rotation
           Pastoral nomadism works on marginal lands…

                                    If you avoid overgrazing!
Image: http://www.geographie.uni-
                        MDC farming:
–     Mixed crop and livestock farming: crops  animals  humans (e.g.
      beef, milk, eggs)
    •    crop rotation, nitrogen fixing crop intermixed with primary crop(s)
–     Dairy farming: within range of market (avoid spoiling), refrigeration
      extends this range
–     Grain farming: e.g. wheat belt
–     Livestock ranching: often on marginal lands in the West, also
      Amazonia, Pampas, Outback
–     Mediterranean agriculture: Horticulture: growing of fruits and
      vegetables, and flowers
–     Commercial gardening and fruit gardening: horticulture, large
      scale, migrant workers
–     Plantation farming: specialize in 1-2 crops, once slavery, now import
How Do you figure out what to grow where?

               Von Thunen Model: Important
 • Market Price
 • Distance
 • Transportation Cost
    – Perishability, (actually covered under transportation cost)

 • Likely on the quiz, test, and final exam.
                         Von Thunen Model

• Distance is a function of land rent and transportation costs.
• Basically, what produces the most profit at each location?
•   Info:
               Issues for commercial farmers:
•       Access to market: Von Thunen model (ring and transport)
    –     Land rent and distance driven… too far  no profit, lose $
•       Overproduction
    –     encourage growth of crops with global demand
    –     price subsidies
    –     buy surplus yield, often donate to foreign governments
•       Unsustainable agriculture
    –      move to more sustainable practices
         •   sensitive land management
         •   Ridge contour tillage
         •   limited use of chemicals
         •   (organic farming)
            Issues for subsistence farmers:

•    Population growth
    – Forest fallow  bush fallow  short fallow  annual
        cropping  multi-cropping
       • Conversion from slash and burn to multi-crop farming
           may not be sustainable
•    Profit motives impact farmers.
    – Lure of money
    – Land loss (legal, and illegal) to for-profit activity
        International trade pressure:

•    conversion of food crops to cash crops
    – may make the economy dependent on foreign
    – if so, cash crop shortfalls or price drops 
        avoidable food shortages
•    drug crops
    – forced or voluntary growth of drug crops
        Strategies for increasing food supply:
   Increase agricultural land
   – marginal lands
      • require careful management for long-term yields
      • must worry about soil salinization, selenium, etc.
      • desertification: human action causes land deterioration
        to a desert-like state.
• Increase land productivity
   – green revolution
      • often requires nutrient inputs (external, cost)
      • often relies on machines (external, cost, needs gas)
      • seed stocks are foreign owned, possibly not self
    Strategies for increasing food supply: (part 2)
    Identify new sources:
    – Cultivate the oceans
        • We are already over-fishing now.
            – (Stock recovery, or risk extinction.)
    – Develop higher protein cereals (decrease meat demand)
    – Promote the consumption of under-used foods, e.g.
         soybeans (soy burgers, etc.)
•     increase trade
    – Reduces local famines
    – Works until you run out globally.
        • Who starves first?
               Food supply crises
Example: Africa
•   Population increases faster than local food supply.
•   Over-planting removes soil nutrients.
•   Trees harvested for firewood.
•   Overgrazing removes grasses and herbs.
•   Desertification is a major problem.
   – The desert has been marching south towards the sea.
•   Warfare, ethnic cleansing, cash crops, and global warming
    exacerbate the problem.
• Review notes.

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