Unit 5 Land and Water Use

Chapter 5 - Land and Water Use

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