Science reviewer 4.2

• Soil Conservation


  • Techniques to prevent erosion
• Erosion


  Carrying off of rock and soil by water/wind
• Contour farmingCrops are planted to run around the slope 


  • Crops are planted to run around the slopes
• Strip Cropping


  • Crops are planted at the same time on the same land so each row is a different crop
  • Used to prevent the washing down of soil
• Crop Rotation


  • One type of crop is planted for one season and another crop is planted for the next season
  • Prevents the continuous loss of the same mineral from the soil
• Rehabilitation


  • Mined out areas are rehabilitated
• Recycling


  Process of reusing a given product
• Land Pollution


  Contamination of land surfaces due to improper disposal of garbage
• Types of waste


  • Biodegradable
  • Non-biodegradable
• Non-biodegradable waste


  • Litter
  • Trash
  • Garbage
  • Used or recycled materials
• Composition of air


  • Nitrogen - 78%
  • Oxygen - 21%
  • Carbon dioxide - 0.4%
  • Other gases - 0.96%
• Air Pollution


  Introduction of harmful substances to the natural environment
• Causes of air pollution

  • Increase in carbon dioxide due to human activities
  • Chemicals produced from burning fossil fuels
  • Sulfur dioxide released when coal is burned
• Clean Air Act of 1900 (R.A. 8749)

  • Aims for a clean and healthy environment
  • Polluting air is punishable by law
  • DOTC shall implement emission standards
  • DOTI/DENR shall establish procedures for motor vehicle inspection
• Philippine water resources


  • 36,000 km longest discontinuous coastline in the world
  • 61 natural harbors, 20 land-locked straits
  • Manila Bay is one of the finest harbors in the Far East
  • Has about 12 navigable rivers
• Philippine marine waters


  • 1,666,300 km for marine fishing
  • 266,000 km coastal waters
  • 1,400,300 km are marine waters
• Inland fishing grounds


  • Rivers, natural and artificial lakes, swamps, and marshes
• Sources of usable water

  • Surface water - rivers and lakes (75% of needs)
  • Groundwater (25% of needs)
• Water pollutants


  • Phosphates from detergents and fertilizers (algal bloom)
  • Mercury from industrial waste (toxic and fatal)
  • Lead (causes headaches, dizziness, insomnia)
  • Sewage (organic waste that forms bacteria causing diseases)
• Other water pollutants


  • Fertilizers and pesticides
  • Oil spills and natural oil leakages
• DENR


  • Constantly monitors and acts as watchdog of the natural environment
• Surface runoff - water that runs across the land surface.
• Suspension - give water a cloudy or muddy appearance.
• River - running water that carries away materials