INTRODUCTON TO WATER QUALITY IN AQUACULTURE Unit 3'1: Fertilization

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INTRODUCTON TO WATER QUALITY IN AQUACULTUREUnit
3.1 Fertilization
Auburn University Department of Fisheries and
Allied Aquacultures
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Why Fertilize?
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How does fertilizer work in water ?
unfertilized
Carnivore
Small fish
Zooplankton
fertilized
Phytoplankton
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Phytoplankton

• Microscopic rootless plants that form the basis
  of an extensive food web.
• Primary aim of fertilization is to encourage
  growth of these organisms.

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Fertilizer will increase fish yield
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Primary nutrients in fertilizer are
Nitrogen
Phosphorus
K
potassium
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Nitrogen cycle in pond waters
fertilizer
Fish pond
phytoplankton
Plant and animal wastes and bodies
Nitrogen release
Bacterial decomposition
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Phosphorous cycle in pond waters
fertilizer
Fish pond
phytoplankton
Plant and animal wastes and bodies
Phosphate release
Bacterial decomposition
Pond bottom soil
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Loss of phosphorous in pond waters
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Types of fertilizer
inorganic
organic
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Forms of inorganic fertilizers
granular
liquid
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Forms of organic fertilizers
animal manure
vegetable by-products
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Application of inorganic fertilizers
platform
bag
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Application of organic fertilizer
liquid
Dry
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Phytoplankton management
Secchi Disk
30 cm
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Using values obtained from the Secchi disc
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Problems to consider when fertilizing

• Rooted aquatic plants
• Turbid water
• Acidic, low alkalinity water
• Excess flow
• Feeding
• Low dissolved oxygen

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Rooted Aquatic Plants
Without phytoplankton
With phytoplankton
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Turbid Water
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Acidic, low alkalinity water
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Excess water
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Feeding
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Low dissolved oxygen
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End of Unit