Hydroponics - Ning

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Hydroponics - Ning Powered By Docstoc


          ดร. จักรกริ ช อนันตศรัณย์
ราวต้นศตวรรษที่ 19 W.F.Gericke มหาวิทยาลัย

• Hydro แปลว่า น้ า (Water)
• Ponos แปลว่า ทางานหรื อแรงงาน (Labor)

Hydroponic = การทางานที่เกี่ยวกับน้ า (Water
  Hydroponics - The growing of
       plants without soil
• Nutrients are delivered to the plant in an
  aqueous solution.

• The scope of gardening is expanded

• Hydroponic gardening takes place on
  every continent in some form for food or
  commercial use.
        General Advantages
•   Higher crop yield
•   Less water required
•   Possibility to grow crops outside of climate
•   No need for crop rotation
•   Continual growth throughout the year
•   Little risk of weeds or parasites
•   Possibility exists to grow outside of our
    General Disadvantages
• Cost (initial, cost to run)
• Higher maintenance (constant supervision,
  pH testing, lighting adjustments)
• Requires specialized knowledge and
            System Types
There are two types of hydroponics systems
 for delivering the nutrient solution:

• Passive

• Active
       Passive Systems
• Basic
• Easier to set up for the novice gardener
• Require materials that retain moisture
  longer (i.e..vermiculite and sand)
• Portable, simple, inexpensive
• Ideal for starting seeds, root cuttings
  and experimental purposes
• Common types: Wick system
                   Drain down system
Wick System
            Wick System
• Wicks anchored in a medium stretch down
 to a reservoir and draw solution upward to
 reach the roots
• Plants do not grow to full maturity because
 of limited aeration and root zone volume
Drain Down System
      Drain Down System
• Solution is poured through the system 1-3
 times daily and drains into a container
 beneath it
• Roots can clog drain channels
• Extremely high maintenance
        Active Systems

• Uses pumps and other devices to pour
 the solution into the system and gravity
 to drain off the excess to be reused.
• Require mediums that drain rapidly,
 such as smooth gravel
  Types of Active Systems
• Nutrient Film Technique (NFT)
• Ebb & Flow
• Top Feed
• Aeroponics
Nutrient Film Technique (NFT)
  Nutrient Film Technique
• NFT uses little or no medium and uses a
 continuous solution flow over the roots
• Can produce large- scale crops cheaply in
 parts of the world where soil quality is poor
• NFT can produce 106 times more lettuce
 annually on a 2 1/2 acre operation than by
 conventional farming
• The greatest problem facing NFT has
  been root die back caused by
  inadequate oxygen in the area around
  the root system
• This causes water stress which causes
  wilting and blossom end rot of fruit
  crops such as tomatoes.
• This system is susceptible to equipment
  failure and problems arise due to
  support of the plant
            Ebb & Flow
• The most popular system due to its low
 maintenance and low cost
• Utilizes a growing bed full of medium
 that is flooded with solution and allowed
 to drain
• Best suited for growing seedlings,
 transplants and ornamental potted
            Ebb & Flow
• There is little risk of equipment failure
  because there is a growing medium that
  retains water and allows oxygen to get
  to the roots
• Ebb & Flow systems allow for uniform
  fill and complete drainage during the
  irrigation cycle thus leading to uniformity
  in plant growth
• This type of system can be made
  automatic with the use of computers
Top Feed
             Top Feed
• Top feed systems use pumps to carry
  the solution to the medium, and gravity
  to drain it back to a reservoir
• These are reliable, require low
  maintenance and can withstand short
  term equipment failure because of the
  growing medium
• They are suitable for large scale
  growing of all types of plants
               Top Feed
• A disadvantage of this system is that it is
  expensive and difficult to set up
• Top feed systems can use a variety of
  growing mediums and are available in a
  wide range of configurations
• Uses sprayers to bathe the roots with a
  nutrient -oxygen mist
• Plants are artificially suspended
• Used most widely in lab studies, but not
  for large-scale commercial use due to
  expense of setup and maintenance
• NASA has experimented with the combination
  of Aeroponics and NFT in order to conserve
  nutrients for the use of hydroponics in space
• The chief advantage of this type of system is
  efficient utilization of greenhouse space by
  arranging the plants vertically
• A disadvantage of Aeroponics is regulating
  the consistency of the sprayers to assure
  constant nutrient flow
    The Nutrient Solution
• The key to success of a hydroponics system
• Contains various combos of nutrients
  specifically engineered to mimic those in soil
• Made up of: Nitrogen, Phosphorous,
  Potassium, Calcium, Magnesium, Sulfur, Iron,
  Manganese, Zinc, Boron, Copper
    The Nutrient Solution
• Nitrogen- Production of leaves and growth of
• Phosphorous- Development of flowers, fruits,
  leaves and stems and growth of roots
• Potassium- Used by cells during assimilation
  of energy
• Calcium- Spurs root growth and helps plant
  absorb potassium
• Magnesium- Helps distribute phosphorous
  throughout the plant
    The Nutrient Solution
• Sulfur- Heightens the effectiveness of
  phosphorous and used in the production of
• Iron- Important in the production of
• Manganese- Aids in the absorption of
• Zinc- Necessary in the transfer of energy
• Boron- Its purpose has not been determined
• Copper- Needed in the production of
               pH Value
• The acidity or alkalinity of the nutrient
• pH readings run from 0-14
  0-6 acidic, 7 neutral, 8-14 alkaline
• The recommended pH is between 6-6.5
                pH Value
• Affected by many factors
  – Temperature
  – Amount of light
  – Evaporation
  – Type of plant
  – Tap water refining
  – Amount of nutrients
• Checking the pH level of the solution is
  vital to healthy plant growth
                pH Value
• Adjusting the pH level of the nutrient
  solution can be done simply
  – Add baking soda to neutralize an acidic
  – Add white vinegar to neutralize a basic
        Growing Medium
• Growing medium is used to lend support
  to the roots and plant
• A variety of growing medium are utilized
  for their individual qualities in various
  types of hydroponics systems
        Growing Medium
• A few popular examples of growing
  medium are:
  – Sand
  – Brick shards
  – Vermiculite/Perlite
  – Gravel
  – Rockwool
  – Sawdust
  – coconut
  – Polyethylene Sheeting
               Criteria factor
• Oxygen dissolution
• Water Content
    • Solution:Air = 1:1
• Media concentration
    • EC
EC = Electrical Conductivity   ( mS/cm) optimum 1 - 4 mS/cm

   CROP          EC VALUE                     CROP            EC VALUE
African Violet    1.0 - 1.2                 Lavender           1.0 - 1.4

 Asparagus        1.4 - 1.8                    Leek            1.6 - 2.0

Avocado Pear      1.8 - 2.6              Lettuce - Fancy       0.3 - 0.8

    Balm          1.0 - 1.4              Lettuce - Iceburg     0.6 - 1.4

  Banana          1.8 - 2.2                  Melons            1.0 - 2.2

    Basil         1.0 - 1.4                    Mint            1.0 - 1.4

   Beans          1.8 - 2.5              Mustard / Cress       1.2 - 2.4

  Beetroot        1.4 - 2.2                   Onion            1.8 - 2.2
• สภาพภูมิอากาศ
                Factor of EC
    – สภาพที่ส่งเสริ มให้อตราการคายน้ าของพืชเพิ่มขึ้น ก็มีผลในการเปลี่ยน EC
      เร็ วขึ้น ค่า EC เปลี่ยนเร็ วกว่าในหน้าฝน ที่มีเมฆมาก อากาศชื้น
• สัดส่ วนของจานวนพืชที่ปลูกต่อปริ มาตรสารละลาย
    – ถังมีขนาดเล็กแต่ปลูกพืชจานวนมาก การเปลี่ยนค่า EC ก็จะเร็ วกว่าถัง
• ค่า EC ตั้งต้นของสารละลาย
    – ค่า EC เริ่ มต้นของสารละลาย มีความแตกต่างจากค่า EC ที่พืชดูดใช้มากๆ
      ค่า EC ก็จะเปลี่ยนเร็ ว เช่น เราเตรี ยมสารละลายปลูกพืชที่มีค่า EC =
      1.8 แต่พืชมีความต้องการค่า EC = 1.0 การเปลี่ยนค่า EC จะเร็ ว
      กว่าเมื่อเราเตรี ยมสารละลายปลูกพืชที่มีค่า EC = 1.1
• ความบริ สุทธิ์ของน้ าและปุ๋ ยที่ใช้เตรี ยมสารละลาย
                         ้               ่
    – ถ้ามีธาตุที่พืชไม่ตองการเจือปนอยูมาก เช่น Na สารละลายก็จะมีการเปลี่ยน
      ค่า EC เร็ วกว่าการใช้น้ าและปุ๋ ยที่มีปริ มาณ Na น้อยกว่า เนื่องจาก ธาตุ
      เหล่านี้ พืชจะไม่ดูดใช้ ดังนั้น จะเหลือสะสมอยูในน้ า ทาให้ค่า EC สู งขึ้น
      อย่างรวดเร็ ว
The Future of Hydroponics
• Advances in lighting technology
• Use will expand to third world countries
• Reduced cost

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