Name: ______Date: ______Per. ______Pg. ____

Notes: Soil

1. What is Soil? Soil is a natural resource; it is made up of broken rock (mineral fragments), air, water, humus

Parent rock: a rock formation that is the source of soil

Bed rock: the layer of rock beneath soil

  1. Soil Texture- Soil particles: proportions of soil particles

Soil texture:

  1. Sand-- sand is largest, <2mm to > 0.05mm
  2. Silt-- medium sized, < 0.05mm to > 0.002mm
  3. Clay-- smallest – invisible to unaided eye, <0.002mm
  1. Soil Structure
  2. Ability of water to infiltrate soil – determined by how soil particles are arranged and if water can infiltrate (soak through) easily

Infiltration: ability of water to move through soil

  1. Soil Fertility

Humus: the dark, organic material formed in soil from the decayed remains of plants

and animals

  1. Soil Horizons
  1. Soil pH-- Acid or base. 7 is neutral; most plants require a pH between 5 and 7.5

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  1. Soil Color – determined by climate and composition
  1. Soil Structure
  2. Ability of water to infiltrate soil – determined by how soil particles are arranged and if water can infiltrate (soak through) easily
  1. Soil Fertility – ability of soil to hold nutrients and supply those nutrients to plants.
  2. Soil Profile – Parent rock- determines type of minerals in the soil

Soil forms in layers; Parent rock is the solid bedrock from which weathered pieces of rock first break off. Climate determines how quickly weathering occurs

  • Residual soil - soil that remains above its parent rock
  • Transported soil – soil that is blown or washed away from its parent rock.
  1. Soil Types
  1. Polar Soils– not fertile, cold with little humus
  1. Temperate Soils
  1. Grasslands– fertile, rich in humus
  1. Forests- clay and iron, but not as deep and rich as grasslands
  1. Prairies– dry – many plants and bushes, not as fertile as grasslands
  1. Desert Soils– thin with little humus, salts, not very fertile
  1. Tropical Soils– soil VERY weathered due to rains that leach nutrients out
  1. Importance of Soil
  2. Nutrients– minerals and other nutrients for plants, plants provide animals food.
  1. Housing– animals!
  1. Plant anchor– plants hold on to soil for support
  1. Water storage– holds water for plants and animals
  1. Soil Conservation
  2. Contour plowing– plow ACROSS the slopes of a hill; the rows act like a series of dams instead of a series of rivers; helps prevent erosion from heavy rains
  1. Strip Cropping– plant 2 different crops in alternating sections perpendicular to the wind
  1. Cover Crop– crops are planted between harvests to replace certain nutrients and prevent erosion; prevent erosion by providing cover from wind and rain.
  1. Wind BreaksWind Breaks – hedge rows or tree breaks – perpendicular to wind – slows wind, can’t pick up as much soil
  1. Terracing – prevents erosion from heavy rains on steep hills; changes one steep field into a series of smaller, flatter fields
  1. Crop rotation - To slow nutrient depletion farmers plant different crops in their fields that use different nutrients.

g. No-till Farming - the practice of leaving old stalks, provides cover from rain; the cover reduces water runoff and slows soil erosion.