Land Use Part I: Agriculture
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Land Use Part I: Agriculture . Food and Nutrition. Foods humans eat are composed of several major types of biological molecules necessary to maintain health : Carbohydrates Sugars and starches metabolized by cellular respiration to produce energy Proteins

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Land Use Part I: Agriculture

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Land use part i agriculture

Land Use Part I: Agriculture


Food and nutrition

Food and Nutrition

  • Foods humans eat are composed of several major types of biological molecules necessary to maintain health :

  • Carbohydrates

    • Sugars and starches metabolized by cellular respiration to produce energy

  • Proteins

    • Large, complex molecules composed of amino acids that perform critical roles in body

  • Lipids

    • Include fats and oils and are metabolized by cellular respiration to produce energy

  • Vitamins and Minerals


Agricultural land use

Agricultural Land Use

  • Agriculture now covers more of Earth’s surface than forests.

    • 38% of planet’s land surface is used for agriculture

      • 26% pasture/rangeland

      • 12% cropland


Using land for agriculture

Using Land For Agriculture

  • Humans need:

    • Most women need ~2,200 kilocalories / day

    • Men, ~ 2,900 kilocalories / day

  • Biologists estimate that there are roughly 30,000 plant species with parts that humans can eat

  • Majority of our food supply (90%) is derived from only 15 plant and 8 animal species

  • Three grains, wheat, rice, and corn, provide almost half of the calories consumed by people

    • These three species are all annual plants

  • 2 out of 3 people on Earth survive primarily on grains

  • 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%.


Chronic hunger and malnutrition

Chronic Hunger and Malnutrition

  • Chronic undernutrition

    • Occurs when people cannot grow or buy enough food to adequately nourish themselves

    • Consequences:

      • Mental retardation, stunted growth, increased susceptibility to infectious diseases

  • Malnutrition

    • Occurs from low-protein diets that are common in countries where subsistence farming is the most common method of food production

  • Nearly 6 million children die prematurely each year from undernutrition, malnutrition, and their effects.


Hunger around the world

Hunger Around the World


Principle types of agriculture

Principle Types of Agriculture

  • There are two Principle Types of Agriculture

    1. Traditional Agriculture –

    Low Input Polyculture

    • Human and animal labor used to produce only enough food for farming family’s survival

      2. Industrialized agriculture

      High Input Monocultures

      • Produce huge output of single crops (monocultures) or livestock (which are often fed monoculture products)


Traditional agriculture low input polyculture

Traditional Agriculture: Low Input Polyculture

  • Many farmers in developing countries use low-input agriculture to grow a variety of crops on each plot of land (interplanting) through:

    • Polyvarietalcultivation

      • Planting several genetic varieties.

    • Intercropping/Polyculture

      • Two or more different crops grown at the same time in a plot.


Polyculture agriculture

Polyculture Agriculture

  • Advantages of polyculture:

    • Crops mature and ready to harvest at different times

    • Provides food throughout the year

    • Soil constantly covered, preventing erosion

    • Less need for fertilizer and water because roots are at different depths, using more of soil and increasing efficiency

    • Creates habitats for natural predators of pest species, reducing need for pesticides and herbicides


Industrial food production high input monocultures

Industrial Food Production: High Input Monocultures

  • Requires large amounts of energy, water, fertilizers, antibiotics, and pesticides; three of which come from fossil fuels

  • Produce huge output of single crops (monocultures) or livestock (which are often fed monoculture products)

  • Accounts for roughly 25% of the world’s cropland

  • Mostly in developed countries, but it is spreading into developing nations


Industrialized food production in the united states

Industrialized Food Production in the United States

  • The U.S. uses industrialized agriculture to produce about 17% of the world’s grain.

    • Relies on cheap energy to run machinery, process food, produce commercial fertilizer and pesticides.

  • About 10 units of nonrenewable fossil fuel energy are needed to put 1 unit of food energy on the table.

  • Industrialized agriculture uses about 17% of all commercial energy in the U.S. and food travels an average 2,400 kilometers from farm to plate.


Sources of protein livestock

Sources of Protein -- Livestock

  • One of the principal uses of animals in agriculture is to transform plant material into high-quality protein

  • In traditional agriculture, livestock graze land, taking nutrients in and then they defecate and return some of the nutrients to the same field

  • In industrial agriculture, livestock are fed grains (corn particularly, which they are not “designed” to do) and not necessarily in a field, so the manure does not fertilize a field

  • Per capita meat consumption has increased 29% between 1950 and 1996

  • 1/5th of the world’s population consume roughly half of the world’s grain production through livestock


Sources of protein seafood

Sources of Protein -- Seafood

  • Seafood is an important protein source.

  • Since 1989, 13 of the 17 major fisheries in the world have declined or become commercially unsustainable.

  • If current practices continue, the world’s fisheries will be exhausted by 2048.

  • Aquaculture (growing aquatic species in pens) is providing an increasing share of the world’s seafood.


Green revolution

Green Revolution

  • In 1960, 60% of the population of developing countries was considered chronically undernourished.

    • Fallen to less than 14% today

  • Due to major improvements in farm production which came 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

  • Green Revolution started by Norm Borlaug.

    • Promoted the use of dwarf, high yielding wheat and rice grown around the world.

    • Do require fertilizers and protection from pests.

    • Borlaug won Nobel Peace Prize.


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