Chapter 7 - 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

\