Lock, Joe T.

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Texas A&amp;M Repository

L-2238Texas Agricultural Extension Service-......,..-.-PUJ~~ H~iNgPUJ~~-----------Joe T. LockExtension Fisheries SpecialistThe Texas A&M University SystemFood shortages limit fish growth in mostTexas farm ponds. Increasing the growth ofmicroscopic plants (phytoplankton) is the keyto increasing fish growth. Microscopic crusta-ceans (zooplankton) feed on the phytoplankton.When both forms of plankton sink to the bottom,they create an organic ooze which feeds aquaticinsects. Small fish feed on the zooplankton andinsects. These small fish are then eaten by bassand other predator fish. Applying fertilize'rs topromote the growth of phytoplankton (the firstpart of this food chain) will usually increaseannual fish production by 100 to 400 percent.Pond owners should be committed to a long-term management program before fertilizationbegins. One-time or haphazard fertilization isuneconomical and often causes aquatic weedproblems. More importantly, since fertilizationincreases the food supply which results in moreand larger fish, if fertilization is stopped, thereis not enough food for the increased weight offish.The following step-by-step guide will helppond owners establish a successfu I pondfertilization program.1. Study the present condition of your pond.Is the pond muddy?Sunlight is necessary for phytoplanktongrowth. If the water is too muddy to see anobject at least 8 inches beneath the surface,see Extension publication L-2161, ClearingMuddy Ponds, for information on how to clearPondFertilizationthe pond. Neither clearing nor fertilization arenecessary for fed catfish ponds.Are the pH and alkalinity satisfactory?Some ponds are too acidic for good fishgrowth or survival, and some are too low inbicarbonates for good phytoplankton growth.Check with your county Extension agent onprocedures for testing your pond water.Are aquatic weeds present?Aquatic weeds absorb the added fertilizer,which prevents beneficial phytoplanktonfrom using it. Your county Extension agentcan provide recom mendations for controll-ing weeds before fertilizing. After rootedaquatic weeds are controlled, shading byphytoplankton hinders their regrowth. If youhave excessively large areas of shallowwater in your pond, weed control may not bepractical.Texas Agricultural Extension Service • Zerle L. Carpenter, Director • The Texas A&M University System • College Station, TexasWhat kinds and sizes of fish are in the pond?If many undesirable fish, such as bullheadcatfish, carp or gar, are in the pond, youshould remove them with rotenone and thenrestock (see Extension publication L-2084,Renovation of Farm Ponds). If you have toomany stunted sunfish (bream) and/or bass,see Special Publication No.2, "Assessmentand Corrective Management for FishPopulations in Small Impoundments"(published by the Texas Chapter, A.F.S.),available from the Texas Agricultural Exten-sion Service, Soil Conservation Service andTexas Parks and Wildlife Department.Fertilizing will produce more undesirable fish,if they are already present, and will notcorrect an unbalanced fish population.How much water flows through the pond?Fertilization is not usually successful if a con-stant flow from springs or creeks flushes theadded nutrients and phytoplankton from thepond.Are you feeding catfish in your pond?Regularly fed fish ponds usually do notrequire fertilization, as the added wasteproducts from fish being fed adequatelyfertilize the water.2. Select a fertilizer.Inorganic fertilizers are recommended forsport fishing ponds. Granular and liquidforms are available; both give satisfactoryresults when properly applied. Comparecosts, availability and ease of application inyour area before selecting either or bothforms.Granular formulations high in nitrogen andphosphorus, such as 20-20-5, 16-20-0 orsimilar analyses, produce good results inmost situations. Ponds that have beenheavily fertilized for several years mayrespond equally well to phosphate alone.Liquid formulations of ammoniumpolyphosphate (10-34-0 or similar analyses)are easy to apply and usually cost less forthe same results.3. Fertilize as often as necessary to maintain aplankton bloom throughout the warm months.Begin fertilizing when the water temperaturereaches 65 degrees F. Earlier application cancause growth of filamentous algae. Fertilizeso that the nutrients are dissolved in the top2 feet of water. Phytoplankton stay near thesurface to absorb sunlight.If· granular fertilizer is used, it should bedissolved in shallow water. Never pourfertilizer into deep water. The best methodis to pour the fertilizer on a wooden platformplaced about 1 foot below the water surface.The platform prevents phosphorus from los-ing its effectiveness by keeping it from con-tact with the bottom mUd. A platform 4 feetsquare is adequate for ponds up to 5 acres.An alternative method for small ponds is toslit the fertilizer bag on one side and placethe bag in shallow water with the open sideup. Pouring fertilizer into shallow water issatisfactory for small ponds, but more will beneeded than with the platform or open bag-method. Apply 100 pounds of granular fer-tilizer per surface acre for the first applica-tion. Follow with 50-pound applications at1-month intervals, or more frequently if need-ed, to maintain the bloom.If liquid fertilizer is used, mix 1 gallon with10 gallons of water and slosh the mixture onthe surfaces of small ponds. In larger pondsthe fertilizer should be mixed into the waterwith an outboard motor or sprayed on thesurface. Liquid fertilizer is heavier than waterand will sink to the bottom if applied un-diluted. Begin with 1 gallon of fertilizer persurface acre. Follow with 1-gallon applica-tions at monthly intervals, or more frequent-ly if needed, to maintain the bloom.A light green color in the water indicates suc-cessful fertilization (plankton bloom). A whiteobject or cupped hand should disappear at12 to 15 inches beneath the water surface.Add more fertilizer as necessary to maintainthis condition. Do not fertilize when thevisibility is less than 12 inches.Cease fertilizing in the fall when the watertemperature drops to 70 degrees F.Liquid fertilizers containing ortho-phosphatesshould not be stored in unheated buildingsduring the winter. Low temperatures causeinactivation of the phosphate. Suspensionscontaining polyphosphates can be storedsatisfactorily at low temperatures.4. Record the dates fertilizer is applied,application rates and results to develop aschedule for future management.Use the following form or a similar one toprovide a basis for continuing fertilizationprograms, for help in identifying problems,and for estimating the cost of increasing fishproduction.5. Contact your county Extension agent or privatefisheries consultants if problems developwithout apparent reason.Farm ponds are complex systems with manyinteracting factors, and results can notalways be predicted. Some common prob-lems, probable causes and remedies are:NO PLANKTONBLOOM:EXCESSIVEFILAMENTOUSALGAE (SCUM)EXCESSIVEAQUATIC WEEDGROWTHCheck pH and alkalinity. Makesure fertilizer is applied nearthe surface of the water andkept off the bottom. Check foraquatic weeds, water clarityand excess water outflow.Stop fertilization until scumdisappears. Reduce nitrogen inthe fertilizer formulation.Tilapia fish will control filamen-tous algae at high stockingrates.Control weeds before addingmore fertilizer. Deepen shallowwater areas if problemscontinue.FERTILIZATION RECORD(Example)Fertilizer Amount Water clarity Water WaterDate formulation applied (how deep can you see) color temperatureApril 5 20-20-5 1001bs. 20 inches light 72 degreesbrownEducational programs conducted by the Texas Agricultural Extension Service serve people of all ages regardless of socioeconomiclevel, race, color, sex, religion, handicap or national origin.Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8,1914, as amended,and June 30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas AgriculturalExtension Service, The Texas A&M University System.5M-6-87, New FISH

Pond Fertilization.

Texas A&M University

L-2238
Texas Agricultural Extension Service
-......,..-.-PUJ~~ H~iNgPUJ~~-----------
Joe T. Lock
Extension Fisheries Specialist
The Texas A&M University System
Food shortages limit fish growth in most
Texas farm ponds. Increasing the growth of
microscopic plants (phytoplankton) is the key
to increasing fish growth. Microscopic crusta-
ceans (zooplankton) feed on the phytoplankton.
When both forms of plankton sink to the bottom,
they create an organic ooze which feeds aquatic
insects. Small fish feed on the zooplankton and
insects. These small fish are then eaten by bass
and other predator fish. Applying fertilize'rs to
promote the growth of phytoplankton (the first
part of this food chain) will usually increase
annual fish production by 100 to 400 percent.
Pond owners should be committed to a long-
term management program before fertilization
begins. One-time or haphazard fertilization is
uneconomical and often causes aquatic weed
problems. More importantly, since fertilization
increases the food supply which results in more
and larger fish, if fertilization is stopped, there
is not enough food for the increased weight of
fish.
The following step-by-step guide will help
pond owners establish a successfu I pond
fertilization program.
1. Study the present condition of your pond.
Is the pond muddy?
Sunlight is necessary for phytoplankton
growth. If the water is too muddy to see an
object at least 8 inches beneath the surface,
see Extension publication L-2161, Clearing
Muddy Ponds, for information on how to clear
Pond
Fertilization
the pond. Neither clearing nor fertilization are
necessary for fed catfish ponds.
Are the pH and alkalinity satisfactory?
Some ponds are too acidic for good fish
growth or survival, and some are too low in
bicarbonates for good phytoplankton growth.
Check with your county Extension agent on
procedures for testing your pond water.
Are aquatic weeds present?
Aquatic weeds absorb the added fertilizer,
which prevents beneficial phytoplankton
from using it. Your county Extension agent
can provide recom mendations for controll-
ing weeds before fertilizing. After rooted
aquatic weeds are controlled, shading by
phytoplankton hinders their regrowth. If you
have excessively large areas of shallow
water in your pond, weed control may not be
practical.
Texas Agricultural Extension Service • Zerle L. Carpenter, Director • The Texas A&M University System • College Station, Texas
What kinds and sizes of fish are in the pond?
If many undesirable fish, such as bullhead
catfish, carp or gar, are in the pond, you
should remove them with rotenone and then
restock (see Extension publication L-2084,
Renovation of Farm Ponds). If you have too
many stunted sunfish (bream) and/or bass,
see Special Publication No.2, "Assessment
and Corrective Management for Fish
Populations in Small Impoundments"
(published by the Texas Chapter, A.F.S.),
available from the Texas Agricultural Exten-
sion Service, Soil Conservation Service and
Texas Parks and Wildlife Department.
Fertilizing will produce more undesirable fish,
if they are already present, and will not
correct an unbalanced fish population.
How much water flows through the pond?
Fertilization is not usually successful if a con-
stant flow from springs or creeks flushes the
added nutrients and phytoplankton from the
pond.
Are you feeding catfish in your pond?
Regularly fed fish ponds usually do not
require fertilization, as the added waste
products from fish being fed adequately
fertilize the water.
2. Select a fertilizer.
Inorganic fertilizers are recommended for
sport fishing ponds. Granular and liquid
forms are available; both give satisfactory
results when properly applied. Compare
costs, availability and ease of application in
your area before selecting either or both
forms.
Granular formulations high in nitrogen and
phosphorus, such as 20-20-5, 16-20-0 or
similar analyses, produce good results in
most situations. Ponds that have been
heavily fertilized for several years may
respond equally well to phosphate alone.
Liquid formulations of ammonium
polyphosphate (10-34-0 or similar analyses)
are easy to apply and usually cost less for
the same results.
3. Fertilize as often as necessary to maintain a
plankton bloom throughout the warm months.
Begin fertilizing when the water temperature
reaches 65 degrees F. Earlier application can
cause growth of filamentous algae. Fertilize
so that the nutrients are dissolved in the top
2 feet of water. Phytoplankton stay near the
surface to absorb sunlight.
If· granular fertilizer is used, it should be
dissolved in shallow water. Never pour
fertilizer into deep water. The best method
is to pour the fertilizer on a wooden platform
placed about 1 foot below the water surface.
The platform prevents phosphorus from los-
ing its effectiveness by keeping it from con-
tact with the bottom mUd. A platform 4 feet
square is adequate for ponds up to 5 acres.
An alternative method for small ponds is to
slit the fertilizer bag on one side and place
the bag in shallow water with the open side
up. Pouring fertilizer into shallow water is
satisfactory for small ponds, but more will be
needed than with the platform or open bag-
method. Apply 100 pounds of granular fer-
tilizer per surface acre for the first applica-
tion. Follow with 50-pound applications at
1-month intervals, or more frequently if need-
ed, to maintain the bloom.
If liquid fertilizer is used, mix 1 gallon with
10 gallons of water and slosh the mixture on
the surfaces of small ponds. In larger ponds
the fertilizer should be mixed into the water
with an outboard motor or sprayed on the
surface. Liquid fertilizer is heavier than water
and will sink to the bottom if applied un-
diluted. Begin with 1 gallon of fertilizer per
surface acre. Follow with 1-gallon applica-
tions at monthly intervals, or more frequent-
ly if needed, to maintain the bloom.
A light green color in the water indicates suc-
cessful fertilization (plankton bloom). A white
object or cupped hand should disappear at
12 to 15 inches beneath the water surface.
Add more fertilizer as necessary to maintain
this condition. Do not fertilize when the
visibility is less than 12 inches.
Cease fertilizing in the fall when the water
temperature drops to 70 degrees F.
Liquid fertilizers containing ortho-phosphates
should not be stored in unheated buildings
during the winter. Low temperatures cause
inactivation of the phosphate. Suspensions
containing polyphosphates can be stored
satisfactorily at low temperatures.
4. Record the dates fertilizer is applied,
application rates and results to develop a
schedule for future management.
Use the following form or a similar one to
provide a basis for continuing fertilization
programs, for help in identifying problems,
and for estimating the cost of increasing fish
production.
5. Contact your county Extension agent or private
fisheries consultants if problems develop
without apparent reason.
Farm ponds are complex systems with many
interacting factors, and results can not
always be predicted. Some common prob-
lems, probable causes and remedies are:
NO PLANKTON
BLOOM:
EXCESSIVE
FILAMENTOUS
ALGAE (SCUM)
EXCESSIVE
AQUATIC WEED
GROWTH
Check pH and alkalinity. Make
sure fertilizer is applied near
the surface of the water and
kept off the bottom. Check for
aquatic weeds, water clarity
and excess water outflow.
Stop fertilization until scum
disappears. Reduce nitrogen in
the fertilizer formulation.
Tilapia fish will control filamen-
tous algae at high stocking
rates.
Control weeds before adding
more fertilizer. Deepen shallow
water areas if problems
continue.
FERTILIZATION RECORD
(Example)
Fertilizer Amount Water clarity Water Water
Date formulation applied (how deep can you see) color temperature
April 5 20-20-5 1001bs. 20 inches light 72 degrees
brown
Educational programs conducted by the Texas Agricultural Extension Service serve people of all ages regardless of socioeconomic
level, race, color, sex, religion, handicap or national origin.
Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8,1914, as amended,
and June 30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas Agricultural
Extension Service, The Texas A&M University System.
5M-6-87, New FISH


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Pond Fertilization.

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Pond Fertilization.

Abstract

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Texas A&amp;M Repository

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