2. Environment in Landscape Horticulture

Components of the landscape horticulture environment are: soil, water, light, temperature, and air.

Soil

• Role of soil in a Plant's Life
  • Provide for plant support- must be sufficiently firm and dense, but preferably retain constant volume, especially if used in containers
  • Source of water and nutrients - must retain moisture and release soluble nutrients
  • Permit diffusion of oxygen to the roots - must have high porosity
• Components of soil
  • Mineral particles - clay, silt, sand
  • Organic materials - plant and animal residues
  • Water - a solution of various substances
  • Atmosphere - key are oxygen and carbon dioxide
• Critical Issues related to soil and plants
  • Mineral Nutrition

    Essential elements required for plant growth:

    Besides C (carbon), H (hydrogen), and O (oxygen) which are derived from the atmosphere and water,

    the essential mineral elements, derived from soil, are:

    N (nitrogen), P (phosphorous), K (potassium), S (sulfur), Ca (calcium), Mg (magnesium), Fe (iron), Na (sodium), Cl (chlorine), Mn (manganese), Zn (zinc), B (boron), Co (cobalt), Cd (cadmium), I (iodine)

    Soil Chemistry

    - pH: degree of acidity or alkalinity

    - affects availability of mineral nutrients

    - typically between pH 4 &9

  • Nutrients available as charged molecules dissolved in water
  • + cations: Ca++, Mg++, NH4++, K+, Na+, H+
  • - anions: OH-, Cl-, CO3--, SO4--

Water

• Primarily important as soil (or medium) moisture

  Water management critical in Horticulture:

  irrigation

  surface

  sprinkler

  subirrigation

• closely associated with mineral nutrition

Light

• Duration affects growth and flowering
• Intensity affects photosynthesis and productivity
• Quality affects development, photosynthesis, and productivity

  Supplemental illumination (artificial light) is important in greenhouses (especially during winter months)

  incandescent

  fluorescent

  high intensity discharge (HID)

Temperature

• Optimal plant growth occurs at different temperatures (40 - 97 F)
• Low-temperature injury (hardiness)
• Frost

  Temperature control

  -mulching

  -tents and greenhouses

Air

• Source of oxygen and carbon dioxide

  Air pollutants

  -ozone

  -sulfur dioxide

  -fluoride

  -smog

• Acid Rain

Continue with Horticultural Technology for Landscape Horticulture or return to Science in Landscape Horticulture.