Feeding a Growing Population

• Certain factors are needed to feed a population adequately.

• Human Nutritional Requirements

  • A healthy diet requires 2500 calories for the average male and 2000 calories for the average female.

  • Healthy diet requires a balanced intake of protein, carbohydrates, and fat.

  • Only 100 known plant species meet the requirements for human nutritional needs.

  • Just 8 species of animal protein supplies over 90% of the world’s needs.

Types of Agriculture

• Cultivated land covers 9% of earth’s landmass and 14% of earth’s biomass.

• Alley Cropping (Agroforestry)

  • Method of planting crops in strips with rows of trees or shrubs on either side.

• Conservation Tillage

  • Leaves at least 30% of crop residue on the soil surface during the critical soil erosion period.

• Contour Farming

  • Farming with row patterns that run nearly level around the hill.

• Crop Rotation

  • Planting a field with different crops throughout the year to reduce soil nutrient depletion.

• High-Input Agriculture

  • Includes the use of mechanized equipment, chemical fertilizers, and pesticides.

• Industrial Agriculture or Corporate Farming

  • A system characterized by high-input agriculture that is focused on maximizing productivity and profitability.

• Intercropping

  • To grow more than 1 crop in the same field.

• Interplanting

  • Growing two different crops in the same area at the same time.

• Locally grown-Farmers’ Markets

  • Farmers’ markets feature foods sold by farmers directly to consumers.

• Low-Input

  • Depends on hand tools and natural fertilizers

• Monoculture

  • The cultivation of a single crop

• No Till

  • Inject seeds into slits or holes in the soil by a machine to minimize soil disturbance.

• Organic Farming

  • A form of agriculture that relies on crop rotation, green manure, compost, biological pest control, and mechanical cultivation to maintain soil productivity and control pests.

• Polyculture

  • Uses different crops in the same space, in imitation of diversity of natural ecosystems.

• Subsistence

  • Agriculture carried out for survival. Usually organic.

• Terracing

  • Graduated terrace steps used to farm on hilly or mountainous terrain.

• Tillage

  • Conventional method in which the surface is plowed which breaks up and exposes the soil.

Agricultural Productivity

• Implies greater output with less input.

• Increases in productivity are linked with pollution, issues of sustainability, safety, and demand for resources.

• Fertilizer

  • Provide plants with nutrients needed to grow healthy and strong.

  • Inorganic Fertilizer

    • Fertilizer mined from mineral deposits and manufactured from synthetic compounds.

    • Chemical fertilizers contain salts that plant roots absorb quickly, but don't provide a food source for microorganisms or earthworms.

  • Organic Fertilizer

    • Fertilizer that originates from an organic source.

    • Improves the quality of the soil.

• Genetically Modified Crops

  • A recent study concluded that GM Crops have reduced chemical pesticides usage by 37%, increased crop yields by 22%, and increased farmer profit by 68%.

Sustainable Agriculture

• Emphasize production and food systems that are profitable, environmentally sound, and energy efficient.

• The Agricultural and Green Revolutions

• First Agricultural Revolution

  • First wide-scale transition of many human cultures from hunting and gathering to agriculture and settlement.

• Second Agricultural Revolution

  • Coincided with the Industrial Revolution that occurred in England.

  • It moved agriculture to generate the surpluses needed to feed thousands of people working in factories.

• First Green Revolution

  • Involved planting monocultures, using high applications of inorganic fertilizers and pesticides and the widespread use of artificial irrigation systems.

• Second Green Revolution

  • Involved genetically engineered crops that produce the most yields per acre.

Controlling Pests

• Types of Pesticides

  • Biological

    • Living organisms to deal with pests. Examples include bacteria, ladybugs, milky spore disease, parasitic wasps, and certain viruses.

  • Carbamates

    • Affect the nervous system of pests.

    • Carbamates have a higher risk of being dissolved in surface water.

  • Chlorinated Hydrocarbons and other persistent organic compounds

    • Chlorinated hydrocarbons are synthetic organic compounds that belong to a group of chemicals known as persistent organic pollutants (POPS).

  • Fumigants

    • Used to sterilize soil and prevent pest infestation of stored grain.

  • Inorganic

    • Broad-based pesticides that include arsenic, copper, lead and mercury.

  • Organic or Natural

    • Natural poisons derived from plants.

  • Organophosphates

    • Extremely toxic but remain in the environment for only a brief time.

• Costs and Benefits of Pesticide Use

  • Pros

    • Kill Unwanted pests

    • Increase the food supply

    • Food is less expensive

    • Reduce labor costs

    • Agriculture is more profitable

  • Cons

    • Can accumulate in food chains

    • Pests develop resistance

    • Pesticides are expensive to purchase and apply

    • Pesticide runoff and it affects aquatic environments.

    • Inefficient