3. feeding methods - fertilization and...

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3 FEEDING METHODS - FERTILIZATION AND SUPPLEMENTARY DIET FEEDING

31 Introduction

At present over 90 percent of finfish and shrimp aquaculture production within third world and developing countries (including Latin America and the Caribbean) is realized within semi-intensive or extensive pond production systems employing a fertilization andor supplementary diet feeding strategy Here in contrast to complete diet feeding the dietary nutrient requirements of the farmed species are met either entirely or partly (in conjunction with an exogenous supplementary diet) through the production and consumption of natural live food organisms within the water body in which the fish or shrimp are cultured

32 Pond Fertilization

321 The pond ecosystem and primary nutrient cycles

Since the aim of a fertilization feeding strategy is to augment the production of natural food organisms within a water body it is perhaps useful to first describe the basic aquatic food chain or ecosystem and the underlying primary nutrient cycles operating within a pond ecosystem Figures 8 and 9 show a generalized model of a simple aquatic ecosystem and an example of a natural pond food web ending in common carp (C carpio) respectively All aquatic ecosystems including a fertilized fish or shrimp pond rely on the simultaneous operation of two interlinked food chains a light dependent ldquoautotrophicrdquo and grazing food chain and a non-light dependent ldquoheterotrophicrdquo or detritus food chain As the name suggests the autotrophic or organic matter synthesizing food chain relies on the fixation of solar energy by green plants during photosynthesis with the production of new organic matter from carbon dioxide and water and the subsequent consumption of these plant organisms by grazing animals Although green plants and in particular phytoplankton are the principal autotrophs or ldquoprimary producersrdquo operating within a pond ecosystem certain non-photosynthetic anaerobic bacteria and blue-green algae are autotrophic in that they are able to synthesize organic matter (ie new cell biomass) from inorganic carbon by using chemical energy derived from the cellular oxidation of inorganic substrates such as hydrogen sulphide sulphur nitrogen divalent iron and hydrogen (collectively these are termed chemosynthetic autotrophs as opposed to the photosynthetic autotrophs) By contrast the heterotrophic or organic matter consuming food chain relies on the microbiological degradation of non-living organic matter or detritus into new microbial biomass with the release of inorganic nutrients and carbon dioxide the new microbial biomass (mainly bacteria) serving as a feed source for protozoa nematodes and other benthic animals and the released inorganic nutrients and carbon dioxide in turn being available for further photosynthetic production by the primary producers or autotrophs

All pond food organisms including autotrophs and heterotrophs consist mainly of carbon-C nitrogen-N and phosphorus-P (ie composition of phytoplankton grown on a nutrient rich medium being about 45ndash50C 8ndash10N and 1P on a dry basis Edwards 1982) and

consequently are dependent on the biological supply of these primary nutrients for their growth The basic chemical and biological pathways involved in the supply and cycling of C N and P within a natural pond ecosystem are shown in Figure 10 11 and 12 respectively From an understanding of these nutrient cycles it can be seen that the natural productivity of an enclosed water body can be increased with careful management through the controlled addition of chemical inorganic fertilizers (by feeding the autotrophic food chain) andor organic manures (by feeding the heterotrophic food chain) Figure 8 Generalised representation of a simple aquatic ecosystem The lightly shaded blocks represent the biomass of each type of organism The stippled arrows show the direction and magnitude of energy flow while the single line arrows indicate the transference of nutrients either through direct consumption excretion or death and bacterial decay Energy is the amount of solar energy taken up by the primary producers (green algae and higher plants) Ecosystems are usually divided into a grazing food chain of large animals and a detritus or decomposer food chain of microorganisms (Source Eltingham 1971)

Figure 9 Schematic representation of a pond food web ending in common carp (Cyprinus carpio Hepher and Pruginin 1981)

322 Preparation of the pond bottom prior to fertilization

The soil of the pond bottom and in particular the mud layer 1 is considered to be the ldquochemical laboratoryrdquo and ldquoprimary nutrient storerdquo of the pond ecosystem and as such

plays a vital role in the maintenance of pond productivity (Figure 10ndash12 Mortimer 1954 Huet 1975 Vincke 1985 White 1986) However the success of a pond fertilization feeding strategy in many instances depends upon the initial drying andor chemical treatment of the pond bottom with lime

3221 Pond drying

The advantages of air drying and exposing the pond bottom to atmospheric oxygen and sunlight prior to fertilizer application have been summarised by Mortimer (1954) Vincke (1985) Clifford (1985) Fast (1986) Stokes and Smith (1987) and Wilson (1987) and include

Improvement in soil texture and primary nutrient availability for future phytoplankton production by facilitating the breakdown and decomposition of organic matter through oxidation with consequent mineralization of the surface mud layer

Reduced mud sediment demand for oxygen once the pond is filled with water A well aerated and partially oxidised soil makes the bottom better suited for

colonization by desired benthic food organisms Oxidation and removal of undesirable metabolites such as hydrogen sulphide (a

by-product of anaerobic respiration of sulphur bacteria) which if allowed to accumulate may inhibit the growth of phytoplankton and the cultured fish or shrimp

Elimination of fish or shrimp predators parasites and their eggs and unwanted aquatic macrophytes

Facilitates the cropping of the cultured fish or shrimp and the removal of excessive mud or silt deposits from the pond bottom the latter being a valuable fertilizer for agricultural crops

1 The pond mud or sediment generally consists of a mixture of settled organic matter or detritus (dead plantanimal

fragments and faecal matter fresh or in a state of bacterialmicrobial colonization and decomposition) live benthic organisms (algae protozoa nematodes oligochaetes polychaetes gastropods and insect larvae) and inorganic minerals The latter may be present as coarse sand or silt particles precipitated mineral salts bound cations adsorbed onto negatively charged colloidal clayhumus particles or as free dissociated cations within the interstitial water of the pond mud (Boyd 1982 Coche 1985)

Figure 10 The carbon cycle

1 Equilibrium depends on pH the solubility of CO2 increasing with pH In addition to the inorganic C forms shown precipitation of calcium carbonate may occur from the

bicarbonate (Ca(HCO3)2 CaCO3 + H2O + CO2) Particulate and colloidal calcium carbonate plays an important role in that it has the capacity to strongly adsorb a variety of biologically active compounds including humic acids and phosphates

Figure 11 The nitrogen cycle

Figure 12 The phosphorus cycle

1 Equilibrium depends on pH the solubility of orthophosphate acid increasing with pH 2 Slow release of orthophosphate from pond sediments particularly under reducing conditions (caused indirectly through metabolism of anaerobic sulphur bacteria)

The drying out period for adequate mud mineralization is usually between five to ten days as evident by the appearance of cracks on the mud surface or by the ability of the pond bottom to support a mans weight without subsiding (Vincke 1985 Clifford 1985 Wilson 1987) For the culture of specific benthic food organisms it is essential that the pond bottom is not lsquobonersquo dry for example a drying period 7ndash10 days and 3 days is usually recommended for the preparation of pond muds for the growth of ldquolab-labrdquo (algal mat primarily composed of blue green algae and diatoms) and ldquolumutrdquo (algae mat primarily composed of filamentous grass-green algae) within brackishwater fish or shrimp ponds respectively (ASEAN 1978) Although ponds are usually dried at the start of each new culture cycle in China fish ponds are normally dried for a 15ndash20 day period only every one to three years (FAO 1983) However pond drying is not normally recommended for those coastal and riverplain soils such as ldquocats clayrdquo and ldquomine overburnrdquo which contain pyrite - FeS2 and other sulphur containing minerals Upon exposure to air these minerals oxidize to form sulphuric acid and iron sulphate compounds (jarosite) the resultant ldquoacid-sulphaterdquo soil is characterized by a very low pH (lt 4) and yellow spots or streaks of jarosite (Coche 1985) Other disadvantages often ascribed to pond drying include 1) loss in time otherwise

used for fish or shrimp production and 2) additional labour and water cost (ie cost of draining and refilling the pond with water including electrical pumping costs)

3222 Liming

According to Thomaston and Zeller (1961) and Boyd (1986) for a freshwater pond to respond properly to fertilization the bottom mud must not be highly acidic and the surface water should have a neutral-alkaline pH (7ndash8) and a total alkalinity and total hardness of 20 mgl or more as calcium carbonate Acidic muds strongly adsorb inorganic phosphates and pond food organisms (particularly phytoplankton) do not grow wellin an acidic environment (pH5ndash6) or in water with a low base carbon and calcium concentration (Miller 1976 Vincke 1985 Fast 1986 Boyd 1986) However these imbalances may be corrected by applying quicklime (CaO) or limestone (CaCO3) to the pond bottom or water column prior to the start of the culture cycle or pond fertilization programme Boyd (1982) lists three basic types of ponds that respond favourably to liming 1) dystrophic pondswith waters heavily stained with humic substances and muds with large stores of slowly decaying organic matter (typical water quality pH 5 ndash 6 alkalinity 1 ndash 5 mgl CaCO3 acidity 0 mgl CaCO3) 2) ponds with waters of low pH and alkalinity because of moderately acid muds and watershed soils (typical water quality pH 55ndash7 alkalinity 3 ndash 15 mgl CaCO3 acidity 0 mgl CaCO3) and 3) dystrophic ponds with waters containing mineral acidity resulting from acid-sulphate soils of watersheds (typical water quality pH 2 ndash 45 alkalinity 0 mgl CaCO3 acidity 10 ndash 250 mgl CaCO3)

The beneficial effects of liming ponds can be summarised as follows

Liming raises the pH and alkalinity of acid waters to desirable levels establishing a alkaline reserve or pH buffering system (Mortimer 1954 Huet 1975 Miller 1976 Boyd 1982 FAO 1983 Yamada 1986)

By virtue of its effect on alkalinity liming increases the availability of carbon for photosynthesis (Mortimer 1954 Miller 1976 Boyd 1982 Fast 1986 Yamada 1986)

Liming raises the pH of the mud bottom to desirable levels and consequently reduces the capacity of the mud to adsorb plant nutrients such as inorganic phosphates thus increasing their bioavailabilityto pond food organisms (Mortimer 1954 Huet 1975 Miller 1976 Boyd 1982 FAO 1983 Fast 1986 Yamada 1986)

By raising the pH of acidic sediments liming creates a more favourable environment for microbial growth and consequently accelerates the decomposition and mineralization of organic matter within the sediment (Huet 1975 Miller 1976 Boyd 1982 Fast 1986 Yamada 1986)

By raising the alkalinity and hardness of water liming serves as direct source of soluble calcium for pond food organisms (Mortimer 1954 Boyd 1982 FAO 1983)

Liming assists in the clarification of turbid waters by facilitating the flocculation and precipitation of organicclay colloids in suspension (including humic acids) there-by improving light penetration for photosynthesis (Mortimer 1954 Boyd and Scarsbrook 1974 FAO 1983 Yamada 1986)

Liming serves as a pond disinfectant by killing fish parasites and their intermediate hosts animal competitors and unwanted green plants (Mortimer 1954 Huet 1975 Miller 1976 Boyd 1982 FAO 1983 Yamada 1986)

By virtue of the above attributes liming therefore increases (all be it indirectly) the natural productive capacity of freshwater ponds with acidic waters and low total alkalinity and hardness (Boyd 1982 Strumer 1987) For example Zeller and Montgomery (1962) and Boyd and Scarsbrook (1974) reported increased live food production (phytoplankton zooplankton and benthic food organims) within fertilized ponds which were pretreated with lime liming increasing the effectiveness of the fertilization strategy employed A similar relationship exists for fish production within such ponds pretreating ponds with lime increasing the effectiveness of inorganic fertilization with increased fish yields For example Arce and Boyd (1975) and Hickling (1962) reported a 249 and 416 increase in Tilapia production respectively within limed over unlimed ponds receiving inorganic fertilizer inputs However it should also be mentioned that not all studies have demonstrated a positive influence of liming on fish production (Swingle 1947 Miller 1976 Boyd 1982) Thus on the basis of liming trials conducted within freshwater fish ponds in Africa Miller (1976) concludes that the use of lime in water of pH greater than 65 appears unnecessary Similarly with the exception of coastal acid-sulphate soils liming is not considered to be essential for saltwater pond preparation seawater exhibiting a strong buffering capacity and having a pH range between 75 to 84 (Sturmer 1987)

According to Boyd (1982) the lime requirement for a fish pond should represent the quantity of calcium carbonate required to raise the pH of the mud to 59 so that the base unsaturation (proportion of acidic cations to total cations on particle exchanges sites) of the mud will be 02 or less and the total hardness (and alkalinity) will be above 20mgl Table 12 shows the recommended lime application rates for fish ponds as determined by the Boyd technique However it should be remembered that the above relationship between base unsaturation and pond alkalinityhardness was determined for ponds in Alabama USA and relationships between mud pH and base unsaturation differ geographically (Boyd 1986)

Table 12 Estimated lime requirement (kg CaCO3ha) needed to increase the total hardness and alkalinity of pond water to 20mgl or greater1

Mud pH in water

Calcium carbonate required according to mud pH in buffered solution 2

79 78 77 76 75 74 73 72 71 70

57 91 182 272 363 454 544 635 726 817 908

56 126 252 378 504 630 756 882 1008 1134 1260

55 202 404 604 806 1008 1210 1411 1612 1814 2016

54 290 580 869 1160 1449 1738 2029 2318 2608 2898

53 340 680 1021 1360 1701 2041 2381 2722 3062 3402

52 391 782 1172 1562 1548 2344 2734 3124 3515 3906

51 441 882 1323 1765 2205 2646 3087 3528 3969 4410

50 504 1008 1512 2016 2520 3024 3528 4032 4536 5040

49 656 1310 1966 2620 3276 3932 4586 5242 5980 6552

48 672 1344 2016 2688 3360 4032 4704 5390 6048 6720

47 706 1412 2116 2822 3528 4234 4940 5644 6350 7056

1 Source Boyd (1982)

2 Lime required (as CaCO3) is estimated from the pH of the pond muds beforeand after the addition of a buffer solution The

mud sample for limerequirement measurement should be dried at room temperature by spreadingin a thin layeron a plastic sheet The dried mud sample is then groundusing a pestle and mortar and passed through a 20-mesh sieve (085mmopenings) for pH analysis The buffer solution is prepared by dissolving20g of p-nitrophenol 15g of boric acid 74g of potassium chloride and105g of potassium hydroxide in distilled water and diluting to one litrein a volumetric flask Place 200g of the dried and ground mud sample intoa 100 ml beaker adding 20ml of distilled water and stir intermittently for one hour Measure the pH of the mud-water mixture with a glasselectrode while stirring The value obtained is the mud pH Nextadd 200ml of the prepared buffer solution to the mud-distilled watermixture and stir intermittently for 20 minutes Set the pH meter atpH 80 with a 11 mixture of buffered solution and distilled waterand then determine the pH of the mud-distilled water-buffer solutionmixture while stirring vigorously If the pH of the mud-distilledwater-buffer solution mixture is below 70 repeat the analysis with100g dry mud and double the liming rate from the Table above (for adetailed description of the method see Boyd 1979)

Ideally the relationship between pH and base unsaturation of muds should be determined for every farm or region and liming rates computed accordingly A simple method for determining the lime requirement of pond muds that does not require data on the relationship between pH and base unsaturation has been developed by Pillai and Boyd (1985) the liming rate (kg CaCO3ha) is simply determined by measuring the pH change in 40ml of buffer solution (10g p-nitrophenol 75g boric acid 37g potassium chloride and 525g potassium hydroxide dissolved and diluted to 1000ml with distilled water the buffer pH being adjusted to 800) caused by adding 20g of ground dried mud (particles lt 085mm) and multiplying the observed pH change by 5600

The above techniques for estimating lime application rates do not apply to acid sulphate soils since these sediments have both exchange and sulphuric acid acidity Singh (1980) recommends a soil tilling (pyrite oxidation) and leaching reclamation procedure followed by liming and inorganicmanure fertilization for the management of acid sulphate soils A procedure for estimating the lime requirement of acid-sulphate soils is given by Boyd (1979) Examples of lime application rates for aquaculture ponds suggested by other workers are shown in Table 13

For the composition and neutralizing value of commonly used liming materials see Boyd (1979) and Tacon (1987a) Although the neutralising effects of quicklime (CaO) and slaked lime (Ca(OH)2) on acid waters is higher and faster than that of agricultural limestone (CaCO3) the latter is generally regarded to be the safest cheapest and most effective liming material for ponds (Boyd 1982) On a general basis liming materials should be added 2 ndash 3 weeks prior to fertilization (Boyd 1982 Miller 1976) and applied by spreading evenly over the pond bottom (in the case of empty ponds) or water surface The residual effects of liming depend on water exchange within the pond and may last for several years if water exchange is not excessive For example Boyd (1979) found that an annual lime application rate of 25 percent of the initial dose of about 4400kgha agricultural limestone was sufficient to maintain adequate water quality and mud pH for an eight year period within annually drained fish ponds in Alabama USA

Table 13 Examples of suggested lime application rates for aquaculture ponds

a Suggested liming rates for the treatment of low soil pH 1

Soil pH

Liming material (lbsacre) 2

Carbonate of lime Slaked lime Caustic lime

4 1487 1417 994

45 1320 1258 898

5 994 924 634

55 660 634 466

6 334 299 239

65 0 0 0 1 Source Clifford (1985)

2 1kg = 2205 lbs 1 ha = 247 acres

b Suggested liming rates for pond muds based on pH and texture of muds 1 Lime requirement (kgha of CaCO3)

Mud pH Heavy loams or clays Sandy loam Sand

4 14320 7160 4475

4 ndash 45 10740 5370 4475

46 ndash 5 8950 4475 3580

51 ndash 55 5370 3580 1790

56 ndash 50 3580 1790 895

61ndash 65 1790 1790 0 1 Source Schaeperclaus 1933 (cited by Boyd 1982)

c Suggested liming guide for aquaculture ponds in Rwanda (Schmidt and Vincke 1981)

Newly constructed ponds with acid water (pH 4ndash65) use of powdered agricultural limestone at a rate of 1500ndash2000kgha by spreading on the dried pond bottom and lightly tilling the lime into the mud surface layer then filling pond with water

Other ponds monthly application of powdered limestone at a rate of 150ndash200kgha

For a review on the use of lime in African countries see Miller (1976)

d Suggested liming guide for aquaculture ponds - general (Huet 1975)

Liming pondwater the use of up to 200 kghaday of quicklime (CaO) Liming pond bottom to control parasites the use of 1000ndash1500kgha of quicklime (CaO) or 1000kgha of calcium cyanamide Liming materials should be spread on pond bottom which is still damp

Liming pond bottom to improve the mud before using other fertilizers the use of 200ndash400kgha of quicklime (CaO) provided that the pond is not acid If the aim of

liming is to increase the pH and alkalinity of an acid pond in principle 200kgha of quicklime (CaO) is generally sufficient to raise the alkalinity by one unit

e Suggested liming guide for African catfish ponds (Viveen et al 1985)

Newly constructed ponds use of agricultural lime at a rate of 200ndash 1500kgha and mixing with the upper layer (5cm) of the dried pond bottom Pond is then filled with water (till 30cm) and left for one week prior to fertilization

Used ponds use of 100ndash150kgha quicklime (CaO) added to damp pond bottom to eliminate pathogens parasites and invertebrate predators Pond is then left for a 7ndash14day period and then filled with water to a depth of 30cm and pH of water adjusted by adding agricultural lime

f Liming rates employed for aquaculture ponds in China (FAO 1983)

Liming pond water use of quicklime (CaO) at a rate of 750ndash900kgha and 900ndash1125kgha for ponds containing 6ndash7cm water and containing little silt and silt respectively For ponds containing a considerable amount of water (unspecified) an application rate of 1875ndash2250kgha month quicklime is used

g Liming rates suggested for car ponds in Hungary (Horvath Tamaacutes and Toumllg 1984 ADCP 1984)

Nursery ponds use of 200ndash500kgha of lime (CaO) on dried bottom for disinfection followed by aeration of pond bottom by tilling

h Liming rates suggested for Colossoma sp in Brazil (Woynarovich 1986)

Nursery ponds use of 150ndash300kgha of limestone (CaCO3) on dried bottom

i Liming rates suggested for Macrobrachium rosenbergii in Panama (MIDA 1984)

Newly constructed ponds use of 500ndash1000kgha of limestone (CaCO3) on pond bottom

j Liming rates suggested for newly constructed rural fish ponds in Thailand (Edwards and Kaewpaitoon 1984)

Acidity of new pond is tested using litmus paper after introduction of water to a depth of 10cm For water pH 45ndash6 500kg quicklimeha For water pH 4ndash45 1250kg quicklimeha After one day the pond should be filled with water and the acidity checked again

323 Chemical fertilization of aquaculture ponds

Chemical fertilizers are applied mainly to increase the primary productivity of aquaculture ponds The chemical nomenclature and composition of the major single and multinutrient

chemical fertilizers used in aquaculture has been presented previously (Section 12 and 312 Tacon 1987a)

3231 Effect on pond productivity and fishshrimp production

Chemical fertilizers act principally on the autotrophic and grazing food chain by directly stimulating phytoplankton production within the pond (Hepher 1962 McIntire and Bond 1965 Hall Cooper and Werner 1970 Djajadiredji and Natawiria 1965 Boyd 1973 Miller 1976 Guerrero and Guerrero 1976 Cruz and Laudencia 1980 Davidson and Boyd 1981 Hepher and Pruginin 1981 Bishara 1978 Rubright et al 1981 Nailon 1985 Olah et al 1986 Pruder 1986 King and Garling 1986 Yamada 1986) For example the studies of Hepher (1962) showed that the production of phytoplankton within chemically fertilized fish ponds in Israel was four to five times higher than equivalent ponds receiving no fertilizer input the primary productivity of chemically fertilized ponds ranging from a carbon uptake of 4ndash8gm2day during the summer (mid-day water temperature 25ndash30degC) to 25ndash5gm2day during spring and autumn (mid-day water temperature 20ndash25degC) According to Schroeder (1978) over 90 of the total primary production is smaller than 40 microns in size As a consequence of their direct effect on phytoplankton production chemical fertilizers also indirectly augment the production of grazing zooplankton (McIntire and Bond 1962 Dendy et al 1968 Hall Cooper and Werner 1970 Lyubimova 1974 Rubright et al 1981 Torrans 1986) and benthic food organisms (Ball 1949 McIntire and Bond 1962 Sumawidjaja 1966 Rubright et al 1981 Boyd 1981) For example Torrans (1986) reports a standard zooplankton biomass range of 2ndash10gm3 within inorganically fertilized static fish ponds

Although aquaculture production within chemically fertilized ponds will vary depending on the feeding habit and density of the culture species stocked considerable increases in fish and shrimp production are possible (Table 14) For example Schroeder (1978) reports that the maximum fish yields attainable with no supplementary feeding (in earthen ponds in Israel) are 1ndash5kghaday and 10ndash15kghaday for ponds receiving no fertilizer input and chemical fertilizers respectively common carp tilapia and silver carp polyculture at 4500ndash9500 fish per hectare Similarly Horvath Tamas and Tolg (1984) report a fish production increase (mainly carp polyculture) within earthen ponds in Hungary of 11ndash25kg and 15ndash30kg from a 200kg fertilizer input of superphosphate or ammonium nitrate respectively However as mentioned previously the success of a chemical fertilization strategy will depend upon the ability of the farmed fish or shrimp species to take advantage of the increased primary productivity within the pond Adult fish and shrimp species which can feed directly on primary autotrophs include Phytoplankton - Silver carp (Hypophthalmichthys molitrix) Indian carp (Catla catla) Tilapia (esculentus aureus niloticus kottae mariae galilaeus leucostictus mossambicus) Bighead carp (Aristichthys nobilis) Benthic algae - Milkfish (Chanos chanos) Tilapia (mossambicus guineensis melanotheron niloticus) Mullet (Mugil cephalus) Rabbit fish (Siganus sp) Rohu (Labeo Rohita) Freshwater prawn (Macrobrachium dayanum M lanchesteri) Metapenaeid shrimp (Metapenaeus ensis M affinis M macleay) Penaeid shrimp (Penaeus vannamei) Vascular aquatic plants - Grass carp (Ctenopharyn-godon idella) Tilapia (rendalli niloticus Mossambicus zillii) Wuchang fish (Megalobrama amblyocephala) Rabbit fish (Siganus sp) Rohu (Labeo rohita) and occasionally freshwater prawns (Macrobrachium sp) For a review of the natural feeding habits of the major cultivated fish and shrimp species see Ling (1969) Wickins (1976) Von Westernhagen (1974) Bowen (1982) Cremer and Smitherman (1980) Bishara (1979) Cruz and Laudencia (1980) Guerrero and Guerrero (1976) Rubright etal (1981) Weidenbach (1982) Swift (1985) Horvath

Tamas and Tolg (1984) Torrans (1986) King and Garling (1986) New (1987) Hunter Pruder and Wyban (1987) and Lilyestrom and Romaire (1987)

Table 14 Reported fish and shrimp production increases within chemically fertilized ponds compared with non-fertilized control ponds

Species Production

increase () Fertilizer used Source

Tilapia (O mossambicus)

440 Phosphate Vander Lingen (1967)

Tilapia sp (hybrid) 82ndash222 Phosphate Lazard (1973)

Tilapia sp 214 Phosphate Strum (1966)

Tilapia (O niloticus) 340 Phosphate George (1975)1

Tilapia sp (male hybrid)

302ndash420 Phosphate Hickling (1962)


174 082 (NPK) Varikul (1965)

Tilapia sp(O mossambicus)

170 882 (NPK) Varikul (1965)

Carp (C carpio) 752ndash945 PhosphateAmmonium Sulphate

Hepher (1963)

Carp (C carpio) 109 082 (NPK) Swingle Gooch amp Rabanal (1963)


Catfish (I punctatus) 565 082 (NPK) Swingle Gooch amp Rabanal (1963)


Mullet (M cephalus) 167 Phosphate El Zarka amp Fahmy (1968)

Shrimp (P stylirostris) 89 PhosphateUrea Rubright et al (1981)

1 Cited by Hepher and Pruginin (1981)

3232 Fertilizer application rates

It is generally accepted that inorganic phosphate-P and nitrogen-N are the two major soluble nutrients normally limiting the algal productivity of aquaculture ponds phosphate-P and nitrogen-N generally being the first limiting nutrients (ie most essential from a pond fertilization viewpoint) within freshwater and brackishwater ponds respectively (Boyd 1982 1986 Miller 1976 ASEAN 1978 Vincke 1985 Smith 1984 Nailon 1985 Yamada 1986 Strumer 1987 Boyd and Minton 1987) It must be emphasized at the outset that no two ponds are alike and that a fertilization programme developed or recommended for one location may be totally unsuitable for another the response of a fertilization programme depending on the ponds morphology hydrology environment bottom sediment and water quality on the aquaculture species cultured and the fertilizer

used and the fertilizer application method and rate employed (Yamada 1986 Boyd 1986) Clearly every farm must be considered as being unique and a personalised fertilization programme developed accordingly However despite this rather daunting picture some generalisations can be made regarding pond fertilization

According to Hepher (1963 1967) there is no biological or economical justification of applying higher fertilizer dosages than 05mg phosphate-Pl or 14mg nitrogen-Nl for freshwater ponds in Israel applications higher than these levels generally being fixed as precipitated phosphates or lost to the environment as gaseous ammonia The above levels are equivalent to a fertilizer application rate of 60kg ha single superphosphate (11kg P2O5ha) and 60kgha ammonium sulphate (13kg Nha) applied at 2-weekly intervals (08ndash10m water depth 8ndash10000 m3 waterha) This fertilizer application rate is currently the standard dose for fertilizing semi-intensive ponds in Israel with densities of 2000ndash3000 fishha (Hepher and Pruginin 1981) Boyd (1982) and ASEAN (1978) suggest chemical fertilization strategies to maintain soluble nitrogen and orthophosphate at 01ndash05mg Pl (Boyd 1982) and 095mg N1 and 011mg Pl (ASEAN 1978) within freshwater and brackishwater aquaculture ponds respectively The beneficial effect of using nitrogen based fertilizers within freshwater ponds has met with variable results (Hickling 1962 Hepher 1963 Miller 1976 Boyd and Sowles 1978 Boyd 1982 Vincke 1985 Yamada 1986) Vincke (1985) suggest that the continued use of N-based fertilizers may not be necessary within tropical freshwater fish ponds due to the high rate of N fixation by free-living bacteria and blue-green algae within these ponds Example of fertilizer application programmes which have been tested and proven under pond farming conditions are shown in Table 15

Although various precise chemical methods exist for estimating the primary productivity of a water body (Boyd 1979 1982 Schroeder 1978 Davidson and Boyd 1981 Olah etal 1986) the effectiveness of a pond fertilization programme can be quickly determined by measuring the turbidity (ie transparency) of the water body by means of a Secchi disk This simple and practical method is based on the assumption that the main source of turbidity within a fish or shrimp pond is the abundance of phytoplankton (Barica 1975 Almazan and Boyd 1978 Boyd 1979 1982) Stickney (1979) and ASEAN (1978) recommend a Secchi disk visibility of 30cm to achieve and maintain proper fertilization readings above (gt35cm) and below (lt25cm) this level indicating under and excessive phytoplankton production respectively If a Secchi disk is not available the rule of thumb is to submerge ones arm to the elbow if one is just able to see the ends of ones fingers the water should be productive enough (FAO 1981) The Secchi disk method is not suitable for shallow brackishwater ponds intended for benthic algal production or for use within turbid water bodies containing high concentrations of suspended clay particles

3233 Factors influencing the action of chemical fertilizers

Apart from the beneficial effect of liming (section 3222) the following factors are known to influence the success or not of a chemical fertilization feeding strategy

1 Sunlight In the presence of adequate inorganic nutrients primary production reaches a maximum value set by the amount of solar energy penetrating the pond water (Schroeder 1978 1980 Wohlfarth and Schroeder 1979) Although Tamiya (1957) and Hepher (1962) state that the maximum primary productivity within tropical waters is equivalent to about 10g of carbon fixed as algaem2day Talling

etal (1973) have suggested that the upper limit for gross primary productivity is 178g of carbon fixedm2day or the equivalent release of 47g of oxygen (in general 26g of oxygen are produced for every gram of carbon fixed during photosynthesis Cassinelli etal 1979 Pruder 1986) According to Pimentel and Pimentel (1979) about 003 of the light reaching an aquatic ecosystem is fixed by phyto-plankton and aquatic plants and is calculated to be approximately 4 times 106 kcalhayear or about one third of that fixed in terrestrial habitats

From the above it follows that increasing water depth water turbidity1 (caused by suspended clay particles) over-cast skies and shading will reduce the amount of light reaching the green autotrophs and consequently will limit the primary production capacity of a pond (Miller 1975 Boyd 1986) Furthermore the continued application of chemical fertilizer beyond a certain level will not result in increased primary productivity the amount of solar energy penetrating the pond water dictating the upper limit for autotrophic production (Hepher 1962 Schroeder 1978 1980)

1 The detrimental effect of water turbidity resulting from clay suspensions may be reduced by treating the pond water with

aluminium sulphate or gypsum (Boyd 1986) barnyard manure (2ndash3 applications of 1 tonacre at 3-week intervals Boyd and Snow 1975) or a cotton-seed meal superphosphate mixture (3 1 100 lbsacre Swingle and Smith 1974)

Table 15 Examples of pond fertilization feeding strategies

FRESHWATER PONDS

1 Freshwater prawn (M LanchesteriM Lanceifrons montalbanense) and Tilapia (nilotica mossambica) polyculture - Philippines (Guerrero and Guerrero 1976)

Biweekly application of 50kgha ammonium phosphate 16200 (NPK) using underwater platforms water depth 06ndash07m

See also Guerrero (1981) for tilapia monoculture using 50kgha ammonium phosphate to maintain productivity and stocking fish two weeks after initial fertilization

2 Tilapia (nilotica) fingerling production - Rwanda (Schmidt and Vincke 1981) Monthly application of 40kgha superphosphate (18) and 20ndash40 kgha

ammonium sulphate or 10ndash20kgha urea and 100kgha agricultural limestone

3 Tilapia growout - Ivory Coast (Lazard 1973 cited by Miller 1976) Monthly application of 60kgha triple superphosphate monthly dose given

in two equal applications in baskets suspended in the surface water 4 Carp (C carpio) fingerling production - Malagasy Republic (Vincke 1970 cited by

Miller 1976) Biweekly application of 20ndash40kgha triple superphosphate and 40ndash 80kgha

ammonium sulphate given every 2ndash3 weeks 5 Tilapia growout - Zambia (Strum 1966 cited by Miller 1976)

Monthly application of 56kgha double superphosphate (38 P2O5) 6 Carp (C carpio H molitrix) and Tilapia (aurea or hybrid) polyculture - Israel

(Hepher 1962) Biweekly application of 60kgha superphosphate (18) and 60kg

ammonium sulphate 7 Carp nursery ponds - Hungary (Horvath Tamas and Toumllg 1984)

After pond drying and disinfection with lime pond half filled (5ndash7 days before fish stocking) with water and 150ndash200kgha ammonium nitrate or

carbamide added Half of the application to be added during pond filling and the remainder given in two applications after the first and second week of nursing Phosphorus should be added in a semi-dissolved state at 100kgha when flooding of the pond occurs

8 General freshwater fish - Alabama USA (Boyd and Snow 1975) Eight to twelve periodic applications per year of 45kgha 20205 (NPK

granular compound fertilizer) applied on to under-water platforms first application followed by two applications at biweekly intervals three applications at triweekly intervals and five applications at monthly intervals

Subsequent studies have shown that nitrogen fertilizers may be greatly reduced or omitted without reducing fish production (Boyd and Sowles 1978)

Dobbins and Boyd (1976) also found that potassium fertilizers are generally unnecessary and that the standard phosphorus fertilization rate of 9kg P2O5haapplication could be reduced by half without significantly decreasing fish production

two to three weekly application of 66kgha ammonium polyphos-phate solution (liquid fertilizer 10340 NPK density 14gml Davidson and Boyd 1981)

9 Milkfish (C chanos) Tilapia (T nilotica) and Snakehead (O striatus) polyculture - Philippines (Cruz and Laudencia 1980)

Biweekly application of 50kgha ammonium phosphate (16200 NPK) 10 General freshwater fish - China (FAO 1983)

Application of compound fertilizer (442 NPK) to maintain concentration of 09 09 and 045mgl respectively

11 General freshwater fish - BrazilHungary (Woynarovich 1985) Biweekly application of 15kgha superphosphate (18) and 30kg ha

ammonium nitrate

BRACKISHWATER PONDS

12 Shrimp (Penaeus stylirostris) growout - USA (Rubright etal 1981) Application of 157kgha pelletised urea (4500) and 67kgha triple

superphosphate 19 days before shrimp stocking and again 7 days after stocking

13 Shrimp (Penaeus sp) growout - EcuadorPhilippines (Clifford 1985) Quotes initial application (while filling the pond) of 168ndash 224kgha urea and

11ndash56kgha triple superphosphate followed by weekly application of 22ndash56kgha urea and 11ndash22kgha triple superphosphate (application methods - platforms suspended perforated bags or dumping into intake water)

14 Shrimp (Penaeus sp) growout - USA (Colvin 1985) Quotes Parker etal (1974) who used weekly applications of 45kgha urea

once the shrimp reached 20mm in length together with a 25 protein pelleted shrimp diet

15 Shrimp (Penaeus sp) growout - Ecuador (MIDA 1985) Quotes substitution of pelleted feeds in Ecuador with weekly applications of

20kgha urea and 7kgha P2O5 final shrimp density 15ndash2m2 16 Shrimp (Penaeus sp) growout - Mexico (unpublished data)

Initial application of 15ndash35kgha urea and 5ndash12kgha P2O5 followed by monthly applications depending on water productivity

17 Shrimp (Penaeus sp) growout - Brazil (unpublished data on commercial sector)

Initial application of 10ndash150kgha urea (mean 25kg) and 5ndash60kg ha triple superphosphate (mean 15kg) followed by monthly applications depending on water productivity

18 Mullet (Mugil capito) growout - Egypt (Bishara 1979) Monthly applications of 20kgha superphosphate or 18kgha super-

phosphate plus 18kgha ammonium nitrate 19 Red drum (S ocellatus) nursery - USA (Colura 1987)

a Fertilization schedule used at the GCCATPWD John Wilson Marine Fish Hatchery in Corpus Christi Texas All fertilizer rates are calculated on a per hectare basis

Day Treatment

1 Fill pond to 13 volume

3 Add 12L phosphoric acid and 28L ammonium nitrate (33N)

6 Spread 455kg of cottonseed meal (CSM) over water surface

8 Finish filling pond

12 Add 12L phosphoric acid and 28L ammonium nitrate

14 Stock approximately 750000 fry

16 Spread 114kg CSM over water surface





b Fertilization schedule used at the TPWD Perry R Bass Marine Fisheries Research Station Palacios Texas All fertilizer rates are calculated on a per hectare basis

Day Treatment

1 Spread 282kg CSM on dry pond bottom fill to approximately 100cm deep

3 Continue filling Add 9L phosphoric acid and 46kg urea (45N)

7 Spread 313kg CSM

10 Spread 313kg CSM stock fry

12 Spread 313kg CSM add 3L phosphoric acid and 46kg urea

15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM

24 57kgha salmon starter diet


20 lsquoLab-Labrsquo (benthic blue-green algal complex) culture for milkfish (C chanos)shrimp ponds - General (ASEAN 1978)

Pond bottom should be first dried for a 7ndash10 day period (not bone dry) Dried chicken manure (insecticide free) should be applied to dry pond bottom at the rate of 350kgha to increase the organic matter content of

pond sediment lab-lab growth being directly related to the organic matter content of the mud - growth being very abundant in soils with 16 organic matter or more In the absence of chicken manure (or other animal manures) chemical fertilizers may be applied at the rate of 50ndash100kgha 18460 (NPK) or 100ndash150kgha ammonium phosphate (16200 NPK) Immediately after fertilization 3ndash5cm of water is introduced into the pond After one week the same amount of fertilizer is applied and the water level is raised to 10ndash15cm The fertilization is repeated after the second week and the water level is raised to 20ndash25cm Additional water is added to the pond as necessary to make up for see-page and evaporation losses Many farmers recommended fertilization every 7 days throughout the fish or shrimp culture period For further details see Padlan Ranoemihardjo and Hamami (1975)

Yamada (1986) quotes the lsquolab-labrsquo fertilization programme of Ballesteros and Mendoza (1976) for milkfish culture in the Philippines Initial application of 100ndash200kgha 18460 (NPK) onto dry pond bottom and then allowing water to enter the pond Additional fertilizer applications of 50ndash100kgha 18460 (NPK) every 10ndash15 days up to one week before stocking One week after stocking further application of 15ndash25kgha 18460 (NPK) repeating this dosage every 10ndash15 days until harvest

Djajadiredja and Poernomo (1973) quote a fertilization programme for the production of lsquokelekaprsquo (benthic algal complex) for milk-fish ponds in Indonesia ponds are first drained and the mud thoroughly tilled so as to make it as soft and fine as possible Fertilizer application of 130kgha urea 65kgha triple superphos-phate and 1000kgha rice chaff (locally known as lsquosekamrsquo) by scattering evenly over the moist pond bottom Immediately after fertilizer application water level in the pond raised to 3ndash10cm After a good growth of benthic algae is noticed water level raised to normal level of 30ndash40cm and fish stocked Djajadiredja and Natawiria (1965) observed that 88ndash281 tons (average 156 ton ha) of lsquokelekaprsquo could be produced in 2 weeks with an application of 500kgha urea However chemical fertilizers are rarely used for benthic algal production in Taiwan preference being rice bran and night soil (Chen 1973)

Proce dure for growing lsquolab-labrsquo can also be used for freshwater fish ponds using an initial fertilization regime of 50kgha 16200 (ammonium phosphate NPK) 22kgha 4600 (urea NPK) and chicken manure at 2000ndash2500kgha (Bautista 1982 Oandasan 1982)

21 lsquoLumutrsquo (benthic grass green flamentous algal complex) for milkfish (C chanos) shrimp ponds - General (ASEAN 1978)

Soft mud bottoms with a pH 68ndash75 favour growth of lsquolumutrsquo Pond should first be dried for a 3 day period and sufficient water allowed to enter the pond to moisten the soil Moist bottom is then seeded with long filaments from older or existing plants (it usually takes 2ndash4 weeks from planting until the pond is ready for stocking) After seeding the pond is flooded to 30cm and 3ndash7 days later is fertilized with ammonium phosphate (16200 NPK) at a rate of 18ndash20gm3 water applied by broadcasting or by dissolving from a platform placed 10cm below the water level After one week the water level raised to 40cm and thereafter weekly applications of fertilizer given at a rate of 9ndash10gm3 water until 6 weeks before the crop is harvested Rows of twigs and small branches should be inserted into the mud bottom (lines 6ndash15m apart) so as to minimise the destructive dis lodging action of wind and

waves on the lsquolumutrsquo With adequate wind breaks the water can be maintained at a depth of 60cm

2 Water exchange For the beneficial effects of liming and chemical fertilizers to be realized in the form of increased phytoplankton production it is essential that the retention time of water in the pond be at least three to four weeks (equivalent to a pond water exchange rate of 5day) Water exchange rates greatly in excess of this will result in fertilizer and liming nutrients being flushed out of the pond before they can be used (Boyd and Snow 1975 Miller 1976 Boyd 1986) Excessive water exchange rates may be a major problem in the tropics during the rainy season

3 Water chemistry In waters with high calcium concentrations (hard water) and elevated pH the phosphate applied in fertilizers may be rapidly lost from the water through precipitation as insoluble calcium phosphate thus rendering it unavailable to the primary autotrophs (Boyd 1982) It follows therefore that phosphate fertilizer application rates should be higher within hard waters of high pH than in softer water with a more moderate pH (Boyd 1986) In view of the above relationship phosphate fertilizers should never be applied at the same time or within one week of liming (Viveen etal 1985)

4 Natural soil fertility Ponds on fertile pasture soils require lower fertilizer application rates than infertile woodland soils (Boyd 1976) Similarly rich alluvial soils with a high organic matter content require lower fertilizer application rates than infertile sandy loam soils for the growth of benthic blue-green algae (lsquolab-labrsquo) within brackishwater fish ponds (Tang and Chen 1967 ASEAN 1978)

5 Previous pond management Newly constructed ponds generally require higher initial fertilizer application rates than ponds with a history of fertilization and accumulated bottom sediments (Hickling 1962 Hepher 1963 Swingle 1965 Boyd 1986)

6 Aquatic weed infestation Large populations of aquatic macrophytes will compete with phytoplankton for available nutrients and sunlight resulting in reduced phytoplankton production (Boyd 1982 Miller 1976 Boyd 1986) Weed infestation may be controlled through liming mechanical cropping or through the use of herbivorous fish species such as grass carp (C idella) Tilapia (T rendalli niloticus mossambicus zillii) or rabbit fish (Siganus sp)

7 Algal taxonomic composition Although chemical fertilization stimulates algal productivity the algal taxonomic composition is generally unpredictable (Boyd 1986) Recommended dissolved nutrient concentrations favouring predominance and growth of specific algal groups include diatoms - 20ndash301 NP (ASEAN 1978) 10ndash201 NP (Clifford 1985) phytoflagellates - 11 NP (ASEAN 1978) phytoalgal

plankton (general) - 441 NPK (Hora and Pillay 1962)

- 41 NP (Swingle and Smith 1939 Nailon 1985)

- 42751 CNP (Hepher and pruginin 1981)

- 50101 CNP (Biomass composition Edwards 1982)

Bacteria (general) - 10051 CNP (Growth medium Edwards 1982)

8 Fertilizer solubility A fertilizer will only be effective if it is soluble Although this is not generally a problem for nitrogen based fertilizers (the majority being very soluble) phosphate fertilizers vary in solubility depending on their particle size and

chemical composition (Table 16 Miller 1976 Boyd 1979 Hepher and pruginin 1981) In this respect liquid fertilizers (if available) are recommended over granular and powdered fertilizers due to their faster solubilization and more uniform distribution of nutrients in the water column (Musig and Boyd 1980 Davidson and Boyd 1981)

Table 16 Percentage dissolution of phosphorus and nitrogen from selected fertilizers after settling through a 2-metre water column at 29degC 1 2

Fertilizers Nutrient solubility ()

Phosphorus Nitrogen

Superphosphate 46 -

Triple superphosphate 51 -

Monoammonium phosphate 71 51

Diammonium phosphate 168 117

Sodium nitrate - 617

Ammonium sulphate - 859

Ammonium nitrate - 988

Calcium nitrate - 987


2 The above solubilities are specific for the study in questionsolubility also varying with fertilizer particle size and

water quality

9 Fertilizer application method and frequency of application The fertilizer application method used can have a profound effect on the success of a pond fertilization regime This is particularly true for granular and powdered phosphate fertilizers which if allowed to come into direct content with the pond bottom will become rapidly adsorbed by the soil particles and so rendering the phosphate unavailable to the planktonic algae To overcome this difficulty phosphate fertilizers should be either dissolved in water prior to distribution or applied within floating perforated cannisters suspended perforated sacks or by placing onto underwater platforms (Figure 13) The latter application methods rely on the gradual dissolution and distribution of the fertilizer by wave action and water circulation within the pond it follows therefore that such devices should not be placed near the pond outlet (Van der Lingen 1967 Vincke 1970 Boyd and Snow 1975 Davidson and Boyd 1981 Viveen etal 1985 Boyd 1982 Sanchez and Quevedo 1987) However it should be emphasised that the fertilization of brackishwater ponds for the production of benthic algae (ie milkfish ponds) is radically different from that of freshwater ponds where the main aim is to produce planktonic algae (Chen 1973 Djajadiredja and Poernomo 1973 ASEAN 1978) For the preparation of ponds for benthic production fertilizers are applied directly onto the exposed and dried pond bottom (Table 15)

For the maintenance of the pond primary productivity fertilizers should be applied on a lsquolittle and oftenrsquo basis preferably at weekly or biweekly intervals throughout the culture cycle the residual effect of an applied fertilizer dosage lasting for only two to four weeks depending the water management strategy employed (Hepher 1963 Miller 1976 Boyd and Snow 1975 Hepher and Pruginin 1981 Viveen etal 1985 Vincke 1985 Boyd 1982)

a) Underwater platform 1

b) Perforated floating can or basket

c) Suspended perforated sack

Figure 13 Mechanical fertilizer application methods 1 The base of the platform should be 15ndash20cm below the water surface andlocated near the pond water inlet or at the end of

the pond from which theprevailing wind comes A single platform is sufficient for ponds up to 7hawhen plankton is grown Suggested platform top sizes for ponds of differentsizes include

Pond area (ha)

Platform top dimensions (m)

1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210

7 225 times 225 Source ASEAN (1978)

324 Organic fertilization of aquaculture ponds

Organic fertilizers are applied mainly to stimulate the heterotrophic food chain of aquaculture ponds Although virtually all biological materials can be considered as potential organic fertilizers the commonest fertilizer used in aquaculture is animal or farmyard manure (ie farm animal faeces with or without urine and bedding material) Apart from being a readily available and inexpensive commodity animal excreta represents a nutrient packed resource containing 72ndash79 of the nitrogen and 61ndash87 of the phosphorus originally fed to the animal (Taiganides 1978) The average nutrient composition of animal manures and other commonly used organic fertilizers has been presented previously (Section 313 Tacon 1987a) However it must be emphasised at the outset that the nutrient composition of animal manure is highly variable (depending on the diet of the animal the age and species of the animal the type and proportion of bedding material present and the handling and treatment of the manure prior to usage) and consequently each manure source must be considered as being unique and chemically analysed accordingly Sadly the majority of published aquaculture production trials involving the use of animal manures rarely report nutrient analyses of the lsquopigrsquo lsquopoultryrsquo or lsquocattlersquo manure used the presence or not of bedding material or whether the quantities of manure applied to the pond were on a dry or fresh weight basis


In contrast to chemical fertilizers which act directly on the autotrophic food chain organic fertilizers act mainly through the hetero-trophic food chain by supplying organic matter and detritus to the pond ecosystem the manure serving principally as a substrate for the growth of bacteria and protozoa which in turn serve as a protein rich food for other pond animals including the cultured fish or shrimp (Figure 14) Whereas autotrophic production within fertilized ponds is limited by available solar energy (Table 17) heterotrophic production will depend upon the carbon and nitrogen content of the added manure and its consequent susceptibility to microbial decomposition (Schroeder 1978 1980 Wohlfarth and Schroeder 1979) The CN ratio of the applied manure will determine its rate of bacterial decomposition in water and hence the time lag between application and increased heterotrophic pond productivity manures with a low CN ratio (lt 50 animal manures green weeds grass oilseed meals) being more rapidly decomposed by bacteria than wastes with a high CN ratio (gt 100 straw sugar cane bagass sawdust Tacon 1987a Sturmer 1987) Schroeder (1980) suggests that the ideal CN ratio for a bacterial growth medium is about 201 It follows from the above that the smaller the particles of organic matter the faster will be the colonization and decomposition by bacteria and protozoans (Geiger 1983) for example fresh animal manure readily disintegrates in water into colloidal particles Schroeder (1980) estimates that the aerobic digestion of organic matter by bacteria fixes about 20ndash50 of the substrate carbon into new bacterial biomass the yield of bacterial biomass obtained by aerobic digestion being about 10 times higher than by anaerobic digestion (McCarty 1972) According to Cassinelli etal (1979) for each gram of organic matter decomposed 12g of oxygen is consumed and that for each gram of carbon fixed during photosynthesis 26g of oxygen is produced These authors

concluded that the major source of oxygen to a shrimp pond was derived through algal photosynthesis and that the major oxygen sink was algal and bacterial respiration (cited by Pruder 1986)

Figure 14 Fate of applied organic fertilizer in aquatic systems (adapted from Edwards 1982 Delmendo 1980 and Moore 1986)

Table 17 Primary productivity and fish yields attainable within chemically fertilized and manured ponds in Israel 1

Fertilizer input Primary productivity

(kghaday) Fish yield

(kghaday)

Control - no input 6 ndash 12 1 ndash 5

Chemical fertilizers 2 30 ndash 60 10 ndash 15

Chemical fertilizer + organic manure 3 30 ndash 60 32 (max)

1 For standing water ponds receiving no supplemental feeds (Schroeder 1980)

2 Ammonium sulphate and superphosphate applied once every 2ndash3 weeks at60kgha

3 Manure application 6 daysweek at a daily dry organic matter loadingrate equivalent to about 3 of the fish biomass (field

dry chicken manureat a rate of 100kg organic matterhaday)

The beneficial effects of organic fertilization on natural pond productivity are well illustrated by the studies of Schroeder (1980) and Rappaport Sarig and Bejerano (1977) and their results are summarised in Table 18 For additional information on the stimulatory effect of manure on pond biota productivity see Tang (1970) Noriega-Curtis (1979) Olah et al (1986) ASEAN (1978) Malecha et al (1981) Lee and Shleser (1984) Barash and Schroeder (1984) Wyban et al (1987) Garson Pretto and Rouse (1986) and Zhang Zhu and Zhou (1987)

Intense organic and chemical fertilization of aquaculture ponds has resulted in fish and shrimp yields as high as 5ndash10 tonshayear or 15ndash32 kghaday with no supplementary feeding (Fish- Tang 1970 Schroeder 1974 1980 Schroeder and Hepher 1979 Moav et al 1977 Wohlfarth 1978 Buck Baur and Rose 1978 Delmendo 1980 Nash and Brown 1980 Edwards 1980 Maramba 1978 Djajadiredja and Jangkaru 1978 ADCP 1979 FAO 1983 Vincke 1985 Zweig 1985 Plavnik Barash and Schroeder 1983 Behrends et al 1983 Shrimp- Wyban et al 1987 Lee and Shleser 1984) However these high production levels can only be achieved by using appropriate management controls and paying particular attention to fishshrimp stocking density and species selection (Schroeder 1978 Wyban et al 1987) For example Schroeder (1978) correlated fish yields in ponds receiving only cattle manure and chemical fertilizers with stocking density and found a linear relationship up to 9300 fishha (ie the carrying capacity of the pond Figure 15) For each fish stocked up to 9300 fishha an annual yield of 075kg fish was obtained (as compared with an annual yield of 1kg for fish ponds employing conventional pelleted feeds Hepher and Schroeder 1974) These results also indicated an efficient manure conversion efficiency into new fish tissue for every kg of fish produced approximately 3ndash35kg of manure dry matter was used (conversion efficiency cited by Hepher and Pruginin 1981) Wohlfarth and Schroeder (1979) report a conversion efficiency of 27 and 35 for cattle and chicken manure for manuring trials conducted at Dor Israel with a polyculture of common carp silver carp tilapia and grass carp By contrast Garson Pretto and Rouse (1986) report a shrimp (P vannamei Pstylirostris) conversion efficiency of 17 and 20 for chicken and cow manure respectively (conversion efficiencies calculated on a manure dry weight basis and for whole shrimp) Recalculation of the data of Wyban et al (1987) with shrimp (P vannamei) ponds receiving only feedlot cattle manure shows a conversion efficiency (dry manurewhole shrimp) of 21 and 11 for shrimp at stocking densities of 5m2 and 15m2 respectively these authors also reported that the carrying capacity of their manured ponds receiving 1800 kg feedlot manurehaweek was equivalent to about 1700 kg shrimpha

Table 18 (a) Standing crops of phytoplankton zooplankton chironomid worms and bacteria in manured and non-manured ponds with or without fish in Israel 1

Natural food organism Without fish With fish

Manured Non-manured Manured Non-manured

Phytoplankton (gDMm3) 2 02ndash43 006 03ndash14 006ndash02

Zooplankton (gDMm3) 3 03ndash424 006 01ndash10 006

Chironomids (100sm2) 79ndash215 1ndash7 1ndash4 0ndash2

Bacteria (1000sml) 4 17ndash27 - 16ndash67 07ndash43 1 Source Schroeder (1980) - water temperature 9ndash15degC using cowshedmanure and a common carp tilapia and silver carp

polyculture 2 Phytoplankton retained on a 50 micron net grams dry weightm

3

3 Zooplankton retained on a 150 micron net grams dry weightm

3

4 Bacteria concentration within the pond water column (for pond bottomswith an organic matter content greater than 1 the

bacterialconcentration is 100ndash1000 times higher on the pond bottom than in theoverlying water column Schroeder 1978)

(b) Natural food organisms found in water and bottom soil of manured and non-manured fish ponds in Israel 1

Manure input Phytoplankton Rotifers Chironomids

(1000sml) (Noml) (No500cm2)

Chicken droppings 2 164 1000 340

Liquid cattle manure 3 56 867 82

Coral manure 4 30 247 38

Chemical fertilizer 5 46 340 43

Control - no input 25 170 59

1 Source Rappaport Sarig and Bejerano (1977)

2 Dried manure allowed to stand covered with water for 7 days and appliedat a rate of 5kg dry matterhaday

3 Dung and excreta containing about 10 dry matter application as forchicken droppings

4 Fresh cow dung also containing remnants of feed and coarse beddingtreated as for poultry droppings

5 20kg ammonium sulphate and 15kg superphosphatehaweek

Figure 15 Relationship between polyculture stocking density and fish yield in standing water earthen ponds receiving fertilizer inputs only (Schroeder 1980)

If maximum benefit is to be gained from the wide variety of live food organisms available within a well fertilized pond (ie phytoplankton zooplankton bacterial enriched detritus macrophytes benthic algae and animals) it is essential that these ponds be stocked with

fish andor shrimp with diverse feeding habits (Stickney 1978 Schroeder 1980 Wohlfarth and Schroeder 1979 FAO 1983 Vincke 1985 Malecha et al 1981 Zweig 1985) Fish polyculture strategies date back to the Chinese Tang Dynasty (7th centuary AD Zweig 1985) and in China rest on three basic principles (FAO 1983)

ldquocomplete use of the pond both in depth from the surface to the benthic zone and over its entire surface area

complete use of all types of natural food present in the pond phyto- and zooplankton benthos aufwuchs detritus aquatic plants and

taking advantage of mutual benefits while avoiding competition for food1 Several different species are therefore reared together in the fattening pond Depending on the type of food available locally one or two of the main species of Chinese carps are chosen silver bighead grass black or mud They are then combined with complementary secondary species on the basis of the principles set out above and the ecological requirements of the species considered for example

i since the droppings of the grass carp are rich in undigested plant fibres they help the development of plankton which feeds silver and bighead carps

ii to control molluscs 75ndash100 black carpsha are added to the pond while to control small fish and red shrimp 450ndash600 carnivorous fish may be added if the pond is drained annually

iii the common carp scours the bottom of the pond to obtain its nourishment and this helps aerate the sediment oxidize organic matter recycle minerals and finally encourages the development of plankton and the growth of plankton-feeding species and

iv nevertheless competition may develop between the common carp and the mud carp the silver and bighead carps or the silver and mud carps which makes it necessary to limit the number of one or the other of these species (common carp 150ndash225kgha silver carp 300ndash450 kgha)rdquo

Out of a total of 25 fish species cultured in China nine species have sufficiently different feeding habits that they can be cultured together at the same time in a single pond grass carp (C idella) and wuchang fish (M amblyocephala) feed on terrestrial plants and aquatic macrophytes silver carp (H molitrix) and bighead carp (A nobilis) feed mainly on phytoplankton and zooplankton respectively black carp (Mylopharyngodon piceus) feed on molluscs (snails) mudcarp (Cirrhinus molitrella) feed on bottom detritus and common carp (C carpio) feed on benthic invertebrates and most of the above food items with the exception of plankton (Zweig 1985) Table 19 shows the natural feeding habits of adult tilapias and other important fish and prawn species Species ratios which have been found to give satisfactory results in fertilized ponds include

1 Common carptilapia (aureus) silver carp 52515 total of 4500ndash9500 fishha (Israel - Schroeder 1978 1980)

2 Silver carpbighead carpgrass carpcommon carp 651412 with a combined density of about 5500ha together with freshwater prawn (M rosenbergii) at density of 79m2 (USA - Malecha et al 1981 for other prawn polyculture studies see Wohlfarth et al 1985 Rouse Naggar and Mulla 1987 and Cohen Raanan and Barnes 1983)

3 Silver carpbighead carpgrass carpwuchang fishcrucian carp(Carassius carassius)common carp 450015004500300030001500ha total 18000 fishha (China - Shan et al 1985)

4 Common carp (50ndash70) silver carp (20ndash30) bighead carp (10) grass carp (5ndash10) and sheat fish (Silurus glanis Hungary ADCP 1984)

5 Silver carpbighead carpgrass carpcommon carp 7500155045001500ha total 15000 fishha silver carpwuchang fishcrucian carpbighead carp grass carpcommon carp 450030003000155045001500ha total 18000 fishha (China - Zhang Zhu and Zhou 1987 for other Chinese polyculture ratios see FAO 1983)

6 Silver carpbighead carpgrass carptilapia (niloticus males) tilapia (aureus males) 250025015075005000ha total 15400 fishha (Alabama USA - Behrends et al 1983)

1 For example in Israel Yashouv (1971) reported a common carp production of 390kgha in monoculture and 714kgha in

polyculture with silver carp (silver carp production 1923kgha both ponds receiving equal inputs of inorganic fertilizers and poultry manure) Yashouv explains the improved growth to be the result of a ldquopositive (synergistic) interaction on the basis of increased food sources Each of the fish species processes a food source thus making it available to the other The faecal pellets of silver carp which are rich in partially digested phytoplankton make this food source available to common carp which otherwise could not utilise the phytoplankton The common carp by digging and ploughing the pond bottom release into the water minute organic matter which is then strained out and utilised by silver carprdquo

The ultimate choice of species ratio and stocking size will depend upon the type of farming activity envisaged (ruralsubsistence or commercially oriented farming activity) the availability and cost of fertilizers and feeds and on the natural productivity of the water body in question For information on the calculation of fish polyculture ratios and stocking densities see FAO (1983) and Horvath Tamas and Tolg (1984)

Table 19 Natural feeding habits of some pond cultured fish and prawn species

Species Reported adult feeding habits

Tilapia 1

- esculentus Phytoplankton

- rendalli Macrophytes attached periphyton

- mossambicus

Macrophytes benthic algae phytoplankton periphyton zooplankton fish larvae fish eggs detritus

- aureus Phytoplankton zooplankton

- niloticus Phytoplankton

- kottae Phytoplankton detritus invertebrates

- mariae Phytoplankton invertebrates

- galilaeus Phytoplankton

- zillii Macrophytes benthic invertebrates

- guineensis Algae detritus sand invertebrates

- melanotheron

Algae detritus sand invertebrates

- variabilis Algae

- leucostictus Phytoplankton detritus

- sparrmanii Periphyton

- shiranus Macrophytes algae zooplankton

- pangani Periphyton

-jipe Periphyton

Milkfish (C chanos) 2 3Algae phytoplankton detritus periphyton

Grey mullet (M cephalus) 2 3 Algae phytoplankton detritus macrophytes

Prawn (M rosenbergii) 4 Benthophagic detritivoreomnivore

1 Bowen (1982)

2 Schroeder (1980)

3 King and Garling (1986)

4 Malecha et al (1981)

3242 Manure fertilization through straight manual application

The stimulatory effect of an animal manure on natural pond productivity will be determined to a large extent by its method of distribution and application (ie quantity and frequency of application) to the pond The better the distribution of the manure over the pond area the better the fertilization effect achieved (Woynarovich 1985 Delmendo 1980 Edwards 1982) Furthermore manures which produce fine colloidal particles are more rapidly colonised and decomposed by bacteria and consequently will be more effective than manures presented in large lumps or heaps (Hepher and Pruginin 1981) Woynarovich (1979) found that when soft fresh animal manure was mixed with pond water and repeatedly spread over the entire pond area that sufficient amounts of carbon compounds were liberated to maintain a high primary productivity This was believed to be due to the fact that approximately 30 of the total dry matter content of the liquid cow manure existed in a colloidal state and thus acted as an ideal substrate for bacterial and protozoan growth on the pond bottom and within the water column (Moav et al 1977) Similarly Schroeder (1980) reported that as much as 40 of the total solids of fresh cow manure remained in suspension in the water column 50ndash60 of which being in the form of inorganic materials However he also noted that approximately 90 of the coarse organic matter settled to the pond bottom after one to two hours and that sediment accumulations of more than a few mm resulted in the development of anaerobic sediment conditions It follows from the above that there is a maximum amount of manure that a pond can aerobically digestunit areaunit time the addition of manure above this maximum level leading to the accumulation of organic matter on the pond bottom and the development of undesirable anaerobic interstitial conditions (Edwards 1982) According to Schroeder (1980) the maximum amount of manure that a pond can safely digest without undesirable anaerobic effects is about 100ndash200kg manure dry weighthaday or 70ndash140kg organic matterhaday (for Israeli pond conditions) These values correspond approximately to the manure produced from 100ndash200 pigs weighing 100kg eachhaday 15ndash30 cows weighing 500kg eachhaday or 2000ndash4000 poultry each weighing 2kg eachhaday (Edwards 1982) To obviate the possible dangers of water deoxygenation within manure loaded and eutrophic ponds (due to unchecked peaks in bacterial growth and phytoplankton blooms) manures should be added as frequently as possible at least daily on a little and often basis (Hepher and Pruginin 1981 Wohlfarth and Schroeder 1979 Schroeder 1978 Woynarovich 1979) Although the oxygen demand of the manure itself is not great if the manure is evenly distributed over the pond surface it is recommended to apply manure to a pond during mid-morning when oxygen levels are rising rapidly due to photosynthesis this in turn would minimise the oxygen demand caused by the bacterial breakdown of the manure itself during the critical pre-dawn hours (Woynarovich 1980 Edwards 1982) In addition since the manure requirement of a pond will depend upon the dietary live food requirements of the fishshrimp biomass present it follows that the manuring rate will have to be increased (up to a maximum safe level) with increasing fish biomass or standing crop (Hepher and Pruginin 1981) Figure 16 shows the relationship between total standing crop and daily manure requirement obtained by Wohlfarth (1978) for Israeli fish ponds Examples of manure fertilization programmes which have been employed by other workers are shown in Table 20 It must be remembered however that the manuring rates shown are pond and farm specific and as such should only be used as tentative lsquoguidelinesrsquo by persons wishing to develop their own pond fertilization programmes

Figure 16 Relationship between manure requirement and standing crop in Israeli fish ponds (Wohlfarth 1978)

Three basic methods are currently employed for the distribution of animal manure to fish or shrimp ponds (Woynarovich 1979)

The dilution of the manure on land and the distribution carried out by hand from the shore or from a small boat This method is normally used for small ponds (Figure 17 A1ndash3)

Soft manure is shovelled into a basket of parallel iron rods (approx 2ndash25cm apart) suspended 10ndash20cm below the water line attached to the side of a boat and dispersed as the boat moves and forces water into the basket (Figure 17 B1)

The use of a pump built into the bottom of a boat the manure is shovelled into a hopper diluted with pumped water and sprayed out into the pond through a flexible hose (Figure 17 C1)

Figure 17 Organic manure distribution methods (Woynarovich 1985)

Table 20 Examples of manure fertilization programmes for pond fish and shrimp

FRESHWATER

1 General fish - Israel (Schroeder 1980)

- Manuring rate computed as dry organic matter at 2ndash4 of the standing fish biomass daily Calculation is based on the dry organic matter content of the manure and so excludes ash The manure should be distributed in liquid or moist form retaining the urine and faeces At this manuring rate with a polyculture of 9000 fishha the fish yields are 20ndash30kghaday (in conjunction with standard inorganic fertilization rates - Table 15)

2 General fish - Panama (MIDA 1985a)

- Recommended manuring rates

dried pig manure - 68kghaday

dried poultry manure - 50kghaday

dried cattle manure - 100kghaday

dried goat manure - 100kghaday

- To ensure a good production of pond food organisms the authors recommend the single application of one months manure supply to the pond two weeks prior to stocking

3 General fish - Brazil (Woynarovich 1985)

- Recommended manuring rates Fresh poultry manure - 500kgha1ndash2 days or 1000kgha1ndash2 weeks Fresh pig manure - 700kgha1ndash2 days or 1400kgha1ndash2 weeks Fresh cattle manure - 1000kgha1ndash2 days or 2000kgha1ndash2 weeks

4 Carptilapia polyculture - USA (Behrends et al 1983)

- Liquid pig manure added daily to the pond at a mean dry matter loading rate of 61kghaday with a combined stocking rate of 15400 fishha (for species ratio see polyculture section of this report 3241) Average total solids content of liquid manure was 04 and supplied an average of 55kg nitrogen 43kg phosphorus (as P2O5) and 33kg carbonhaday Liquid pig manure was composed of a mixture of faeces urine and wasted feed

5 Carp polyculture - China (Shan et al 1985)

- Liquid pig manure added to the pond at a nominal daily rate of 2 (dry weight basis) of the fish biomass (18000 fishha for species ratio see polyculture section of this report 3241)

6 Tilapia hybrid (hornorum males X mossambica females) - Costa Rica (Gonzalez et al 1987)

- Dried poultry manure added daily to the pond at a rate of 110kghaday 15 days prior to stocking (15 fishm2) the limed pond bottom was treated with 1200kg dried poultry manure The poultry manure used had a moisture content of 9ndash14 and a ash content of 25ndash28 A manurefish conversion efficiency of 79 was obtained over the 255 day culture cycle (conversion efficiency includes manure used for pond preparation and daily application rates) with a extrapolated total fish production of 4926kghayear (4363kghayear - net production)

- Manure application rates of 55ndash175kghaday were also tested

7 Tilapia - Rwanda (Schmidt and Vincke 1981)


General animal manure 300ndash500kgha2weeks (T nilotica spawning ponds)

500kgha2weeks (T nilotica fingerlings 5m2)

Cow manure 300kghaweek Horse manure 2000ndash3000kghamonth Poultry manure initial application of 2500kgha followed by monthly application of 1000kgha (T nilotica fingerlings 2m2)

8 Red drum - USA (Colura 1987)

Manuring nursery ponds with cottonseed meal (for application rates see Table 15)

9 Carp polyculture - Hungary (Olah et al 1986)

- Liquid pig manure with a mean dry weight of 10 applied daily using a rotary sprinkler at a rate of 2m3haday Polyculture employed consisted of silver carp (3500ha mean weight 190g) and common carp (1800ha mean weight 150g)

- Sedimented raw domestic sewage applied daily using a rotary sprinkler at a rate of 100m3haday Polyculture employed consisted of silver carp (1500ha mean weight 190g) bighead carp (800ha mean weight 180g) common carp (1400ha mean weight 200g) and grass carp (300ha mean weight 170g)

- Woynarovich (1980) reviews the use of pig manure for fish production and describes manuring rates (by daily water dispersion) of 300ndash600kg haday for pig manure 1000ndash1500kghaday for the thick liquid phase of the manure and 12ndash25m3haday for commercial piggery sewage in Hungarian polyculture fish ponds

10 Tilapia nilotica - Thailand (Edwards et al 1984)

- Liquid Bangkok cesspool slury applied daily at an organic loading rate of 150kg COD (Chemical Oxygen Demand)haday stocking density of 1fishm2 The total solids (TS) and total volatile solids (TVS) content of the cesspool slury used varied between 1375ndash2942g1 (mean 20g1) and 949ndash 2267g1 (mean 139g1) The mean COD of the cesspool slury used was 287g1

ponds receiving an equivalent dry matter loading rate of 757ndash 1245kghaday

- For further information on the use of human waste waters in aquaculture see Edwards (1984) and Johnson Cointreau (1987)

11 Tilapiafreshwater prawn polyculture - USA (Teichert-Coddington et al 1987)

- Liquid pig manure applied daily at a rate of 17 or 51kghaday (dry matter basis) Highest prawn production observed with the lowest manuring rate tested Polyculture consisted of 3 prawn post larvaem2 with T nilotica and T aurea fingerlings at 08m2

12 Tilapiafreshwater prawn polyculture - USA (Rouse Naggar and Mulla 1987)

- Ponds fertilized prior to stocking with dry chicken manure at a rate of 1000kgha followed by weekly applications at 200kgha Polyculture consisted of a freshwater prawn density of 35ndash4 post-larvaem2 and a tilapia (fry or fingerling) density of 05ndash15m2 (T niloticaT aurea)

BRACKISHWATERMARINE (see also Table 15 for lsquolab labrsquo production)

13 Shrimp (P vannamei) - USA (Wyban et al 1987)

- Ponds fertilized with feedlot cattle manure at a rate of 1800kghaweek (shrimp density 5ndash10m2) Moisture content of manure not given However since the application rate used was based on the results of the study of Lee and Shleser (1984) it is assumed that the manure application rate employed refers to the use of sun-dried manure

14 Shrimp (P stylirostrisP vannamei) - Panama (Garson Pretto and Rouse 1986)

- Ponds fertilized with 910kgha (dry weight) of chicken manure or cow manure 60 days prior to stocking and thereafter applied every 2 weeks at a rate of 450kgha Stocking density employed was 5 shrimpm2 Average shrimp yield (tails only) over a 120-day production cycle where reported as 262kgha (chicken manure) and 218kgha (cattle manure)

consequently are dependent on the biological supply of these primary nutrients for their growth The basic chemical and biological pathways involved in the supply and cycling of C N and P within a natural pond ecosystem are shown in Figure 10 11 and 12 respectively From an understanding of these nutrient cycles it can be seen that the natural productivity of an enclosed water body can be increased with careful management through the controlled addition of chemical inorganic fertilizers (by feeding the autotrophic food chain) andor organic manures (by feeding the heterotrophic food chain) Figure 8 Generalised representation of a simple aquatic ecosystem The lightly shaded blocks represent the biomass of each type of organism The stippled arrows show the direction and magnitude of energy flow while the single line arrows indicate the transference of nutrients either through direct consumption excretion or death and bacterial decay Energy is the amount of solar energy taken up by the primary producers (green algae and higher plants) Ecosystems are usually divided into a grazing food chain of large animals and a detritus or decomposer food chain of microorganisms (Source Eltingham 1971)

Figure 9 Schematic representation of a pond food web ending in common carp (Cyprinus carpio Hepher and Pruginin 1981)

322 Preparation of the pond bottom prior to fertilization

The soil of the pond bottom and in particular the mud layer 1 is considered to be the ldquochemical laboratoryrdquo and ldquoprimary nutrient storerdquo of the pond ecosystem and as such


3221 Pond drying


















3222 Liming













Mud pH in water


79 78 77 76 75 74 73 72 71 70

57 91 182 272 363 454 544 635 726 817 908

56 126 252 378 504 630 756 882 1008 1134 1260

55 202 404 604 806 1008 1210 1411 1612 1814 2016

54 290 580 869 1160 1449 1738 2029 2318 2608 2898

53 340 680 1021 1360 1701 2041 2381 2722 3062 3402

52 391 782 1172 1562 1548 2344 2734 3124 3515 3906

51 441 882 1323 1765 2205 2646 3087 3528 3969 4410

50 504 1008 1512 2016 2520 3024 3528 4032 4536 5040

49 656 1310 1966 2620 3276 3932 4586 5242 5980 6552

48 672 1344 2016 2688 3360 4032 4704 5390 6048 6720

47 706 1412 2116 2822 3528 4234 4940 5644 6350 7056









Soil pH



4 1487 1417 994

45 1320 1258 898

5 994 924 634

55 660 634 466

6 334 299 239


2 1kg = 2205 lbs 1 ha = 247 acres



4 14320 7160 4475

4 ndash 45 10740 5370 4475

46 ndash 5 8950 4475 3580

51 ndash 55 5370 3580 1790

56 ndash 50 3580 1790 895































Species Production










174 082 (NPK) Varikul (1965)


170 882 (NPK) Varikul (1965)


Hepher (1963)





















FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER












































3221 Pond drying


















3222 Liming













Mud pH in water


79 78 77 76 75 74 73 72 71 70

57 91 182 272 363 454 544 635 726 817 908

56 126 252 378 504 630 756 882 1008 1134 1260

55 202 404 604 806 1008 1210 1411 1612 1814 2016

54 290 580 869 1160 1449 1738 2029 2318 2608 2898

53 340 680 1021 1360 1701 2041 2381 2722 3062 3402

52 391 782 1172 1562 1548 2344 2734 3124 3515 3906

51 441 882 1323 1765 2205 2646 3087 3528 3969 4410

50 504 1008 1512 2016 2520 3024 3528 4032 4536 5040

49 656 1310 1966 2620 3276 3932 4586 5242 5980 6552

48 672 1344 2016 2688 3360 4032 4704 5390 6048 6720

47 706 1412 2116 2822 3528 4234 4940 5644 6350 7056









Soil pH



4 1487 1417 994

45 1320 1258 898

5 994 924 634

55 660 634 466

6 334 299 239


2 1kg = 2205 lbs 1 ha = 247 acres



4 14320 7160 4475

4 ndash 45 10740 5370 4475

46 ndash 5 8950 4475 3580

51 ndash 55 5370 3580 1790

56 ndash 50 3580 1790 895































Species Production










174 082 (NPK) Varikul (1965)


170 882 (NPK) Varikul (1965)


Hepher (1963)





















FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER



















































3222 Liming













Mud pH in water


79 78 77 76 75 74 73 72 71 70

57 91 182 272 363 454 544 635 726 817 908

56 126 252 378 504 630 756 882 1008 1134 1260

55 202 404 604 806 1008 1210 1411 1612 1814 2016

54 290 580 869 1160 1449 1738 2029 2318 2608 2898

53 340 680 1021 1360 1701 2041 2381 2722 3062 3402

52 391 782 1172 1562 1548 2344 2734 3124 3515 3906

51 441 882 1323 1765 2205 2646 3087 3528 3969 4410

50 504 1008 1512 2016 2520 3024 3528 4032 4536 5040

49 656 1310 1966 2620 3276 3932 4586 5242 5980 6552

48 672 1344 2016 2688 3360 4032 4704 5390 6048 6720

47 706 1412 2116 2822 3528 4234 4940 5644 6350 7056









Soil pH



4 1487 1417 994

45 1320 1258 898

5 994 924 634

55 660 634 466

6 334 299 239


2 1kg = 2205 lbs 1 ha = 247 acres



4 14320 7160 4475

4 ndash 45 10740 5370 4475

46 ndash 5 8950 4475 3580

51 ndash 55 5370 3580 1790

56 ndash 50 3580 1790 895































Species Production










174 082 (NPK) Varikul (1965)


170 882 (NPK) Varikul (1965)


Hepher (1963)





















FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER














































Mud pH in water


79 78 77 76 75 74 73 72 71 70

57 91 182 272 363 454 544 635 726 817 908

56 126 252 378 504 630 756 882 1008 1134 1260

55 202 404 604 806 1008 1210 1411 1612 1814 2016

54 290 580 869 1160 1449 1738 2029 2318 2608 2898

53 340 680 1021 1360 1701 2041 2381 2722 3062 3402

52 391 782 1172 1562 1548 2344 2734 3124 3515 3906

51 441 882 1323 1765 2205 2646 3087 3528 3969 4410

50 504 1008 1512 2016 2520 3024 3528 4032 4536 5040

49 656 1310 1966 2620 3276 3932 4586 5242 5980 6552

48 672 1344 2016 2688 3360 4032 4704 5390 6048 6720

47 706 1412 2116 2822 3528 4234 4940 5644 6350 7056









Soil pH



4 1487 1417 994

45 1320 1258 898

5 994 924 634

55 660 634 466

6 334 299 239


2 1kg = 2205 lbs 1 ha = 247 acres



4 14320 7160 4475

4 ndash 45 10740 5370 4475

46 ndash 5 8950 4475 3580

51 ndash 55 5370 3580 1790

56 ndash 50 3580 1790 895































Species Production










174 082 (NPK) Varikul (1965)


170 882 (NPK) Varikul (1965)


Hepher (1963)





















FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER


















































Soil pH



4 1487 1417 994

45 1320 1258 898

5 994 924 634

55 660 634 466

6 334 299 239


2 1kg = 2205 lbs 1 ha = 247 acres



4 14320 7160 4475

4 ndash 45 10740 5370 4475

46 ndash 5 8950 4475 3580

51 ndash 55 5370 3580 1790

56 ndash 50 3580 1790 895































Species Production










174 082 (NPK) Varikul (1965)


170 882 (NPK) Varikul (1965)


Hepher (1963)





















FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER

































































Species Production










174 082 (NPK) Varikul (1965)


170 882 (NPK) Varikul (1965)


Hepher (1963)





















FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER






















































FRESHWATER PONDS
























ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER





















































ammonium nitrate

BRACKISHWATER PONDS















Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER















































Day Treatment













Day Treatment



7 Spread 313kg CSM



15 Spread 313kg CSM

17 Spread 313kg CSM


21 Spread 313kg CSM

23 Spread 313kg CSM



























Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER

































































Phosphorus Nitrogen

Superphosphate 46 -










water quality








Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER
















































Pond area (ha)


1 085 times 085

2 125 times 125

3 150 times 150

4 170 times 170

5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER











































5 190 times 190

6 210 times 210











(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER
















































(kghaday)


















3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER





















































3


3






































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER
















































































Tilapia 1



- mossambicus









- melanotheron


- variabilis Algae





-jipe Periphyton




1 Bowen (1982)

2 Schroeder (1980)












FRESHWATER











































2 Schroeder (1980)












FRESHWATER


















































FRESHWATER











































3. feeding methods - fertilization and...

Documents