Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 1 - Soilless Culture - Coggle Diagram
Chapter 1 - Soilless Culture
Where it can be adapted?
Indoor greenhouse culture
Atomic submarines (specialised culture) for growing fresh vegetable for crews
Outdoor field culture
What is soillness Cultivation
Plant growing in an inorganic or organic material and periodically watered with soilless culture.
Hydroponic system
Open Hydroponic System
One-way passage of nutrient solution
Closed Hydroponic System
Circulation System
Surplus solution is recovered, replenished and recycled
Types of Hydroponic systems
Deep Flow
Nutrient pump is used to prevent localised depletion of nutrient and to aerates nutrient solution
Roots bathed in flowing stream of nutrient solution (15-20cm depth)
Plants are supported on rafts of styrofoam boards
Aeroponics
Improve aeration as roots are growing in air
save water and nutrients
Use submersible pump to force nutrient solution into the spraying nozzle to produce fine mist
A small reservoir of water at bottom of vessel for continuous supply of water via pump
Roots suspended in the air and bathed in fine mist of nutrient solution
Standing aerated
Daily addition of water and periodically changing of nutrient solution
For plant nutrition studies but limited for commercial application
Root suspended in aerated water
High cost (chemical and water)
Nutrient Film Technique
Plant roots suspended in a thin layer an slow-moving stream of nutrient solution
Nutrient solution flows from top to the lower end by gravity
Problem/cons
Plants at lower end has lower oxygen and content of nutrient solution and it will affect the growth
As mat thickens and becomes denser, nutrient solution will move over the top and down the outer edge of mat, reducing its contact with the entire root
Increae of root mat will decrease the flow rate
Solution
Trough should be no longer than
9m
in length and minimum
30.5cm
wide
The plants set in the through at the spacing recommended for that crop, e.g. purple cabbage.
Significance of Hydroponics
Helps to provide purified water in space
Maintain balance oxygen and carbon dioxide in space
Providing fresh vegetable in many parts of the water including deserts and little arable land
Supply food for astronaut
Use seawater through desalination if no fresh water
Advantages of hydroponics
Reduce pollution from water run-off
Reduce soil-borne plant diseases
Save water and nutrients
Better control on growth
Maximum yield are possible
Better control on nutrient concentration and pH
Less space required
Clean, light and mechanised
Reduced labour
No crop rotation necessary
Crops can grow even no suitable soil
Disadvantages
Easy spread of diseases in closed system
Requires active attention
Requires specialist
Requires research for optimised growth
High cost
Pump failure can wipe out crops
Rooting medium for Aggregate Culture
Inorganic
Sand
perlite
Gravel
Rockwool
vermiculite
organic
Sawdust
Pine bark
Peat moss
Coconut fibres
Intermittent flow vs Drip Nutrient
Intermittent Flow - Only periodically contact with plant roots
Media will hod the moisture to hydrate root
suitable for plants that root cannot submerge over long period such as tomatoes, cucumber and pepper etc.
Drain cycle improve oxygen contact with the roots
Nutrient solution is pumped from reservoir to growtray periodically and pump is switched off to drain
A closed system
Drip nutrient - Nutrient solution is slowly applied as drops onto rooting medium
Nutrient is applied slowly as drop onto roots
Plant is grow in a bag or pot of medium
Open system
Small holes at bottom for drainage of excess water
Important components in nutrient solution
Inorganic salts
Use greenhouse grade
Use nitrate salt
Use fertilizer with high soluble salt - etc
calcium nitrate
instead of calcium suphate (low solubility)
Sulphates are commonly used
Iron, manganese and zinc are best supplied as chelated salted
Stock solution
Water quality
Suitability of water for irrigating potted plants
Different plant have different requirements (N,P &K)
Plants grown for fruit or root production -
low level of nitrogen
and
high levels of phosphorus and potassium
Plants harvested for their leaves - requires
nitrogen
for
vegetative growth
Low supply of potassium = poor quality fruit
Stock Solution
Hoagland Solution - Widely used in USA
Prepare 150x concentrated stock solutions
Solution A, Calcium nitrate & iron chelate EDTA
Solution B
EC measures ion content in nutrient solution
EC does not determine what differential change in elemental concentration may have taken place in order to add back what was removed, element by element
pH 6-6.5
Use electrical conductivity meter to measure the concentration of nutrient solution
pH is less critical in flowing solution culture system than static as long as pH remains between 5.0-7.0
Acidification enhances their ability to absorb certain elements, such as iron
pH should be not continuously adjusted but allow it to seek its own level naturally