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FISHERIES AQUATIC AND MARINE

Tilapia

Description

TilapiaTILAPIA

Tilapia are sometimes known as "aquatic chicken", due to their high growth rates, adaptability to a wide range of environmental conditions, ability to grow and reproduce in captivity and feed on low trophic levels. As a result, these fishes have become excellent candidates for aquaculture, especially in tropical and subtropical regions. Indeed, tilapia culture has been expanding rapidly, and is now practiced in more than one hundred countries worldwide.
(Source: Department of Agriculture – Bureau of Agricultural Research, Date accessed 24 March 2014)

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Cage Culture

Tilapia cage culture is growing tilapia in cages made of nylon nettings and bamboo frames that are floated, submerged or fixed at the bottom. It utilizes bodies of water such as dams, rivers, lakes, bays, reservoirs and coves. This is one of the effective technologies used in raising tilapia. It started out in 1974 in Sampaloc Lake and Laguna Bay and being practiced now in different regions like in Magat Dam Reservoir in Region II.

The following are the advantages of tilapia cage culture:

  • easier handling, inventory and harvesting of fish
  • better control of fish population
  • efficient control of fish competitors and predators
  • effective use of fish feeds
  • reduced mortality
  • high stocking rate
  • total harvesting and swift or immediate return of investment
  • less manpower requirement
  • minimum supervision

Site Selection

Water circulation

The Magat Dam has water current circulation throughout the area that gives a continuous flushing of water inside the cages, making dissolved oxygen highly available to fish and wash out metabolites. Wind direction from northeast to southeast or vice versa prevails in the months of March to August. The prevailing winds augment the distribution of natural fish food within the dam.

Protection from winds and waves

Locate the site in waters protected from strong wind action and water currents caused by flush flood or heavy runoff. In the Magat Dam, there are few floating debris; the quantity increases as the wind changes its direction and force. However, this could be checked by providing floating bamboo barricades or wave breakers facing the direction of the wind.

Dissolved oxygen concentration

The ideal range of dissolved oxygen concentration on the water must be at least 3 ppm (parts per million). For tilapia, a lesser ppm is not considered lethal. However, growth and reproduction is greatly affected.

Temperature

This is one factor that plays a major role in the growth of the fish stock. The suggested range is from 20°C to 30°C. The lethal temperature levels are 12°C and 42°C.

Pollution

The fish-farmer should know the effect of thermal, biological and chemical pollutants to the fish stock which may come from domestic, industrial and agricultural sources. pH Level. To enhance a better growth, the recommended pH range is 6.8 to 8.0.

Accessibility

The site must be accessible to land and water transportation to facilitate bringing in of inputs and marketing of produce.

Other factors

One social problem existing in any fishery establishment is poaching. Poachers get into the project at night, bore hole on nettings to let the stock escape, then set gill net on surroundings of the project. This gives a bountiful catch overnight. This problem can be remedied by the management by establishing good public relation with the people in the vicinity. Another consideration is the source of fingerlings for periodic stocking.

Structural Design and Construction of Cages

There are two types of cage design — fixed and floating. The fixed cage is suitable with a water depth of 1 to 5 meters and the usual size is 50 to 200 square meters.The floating fish cage, on the other hand is from 5 meters deep and about 50 x 25 x 3 cubic meters depending on the area where the fish cage is placed. It is supported at the bottom with a stone weighing 40 to 100 kilos and covered with a net to prevent the fishes to escape.

The success of the project depends on the quality of breeds or species of fish as well as the production capability of the selected site in enhancing the maximum growth of the fish. Tilapia species is widely used as fish stock because it grows fast. It takes only four months for fingerlings to reach an average weight of 100 grams.

The design of fish cages is determined by the behavior of the culture species. For Tilapia nilotica, which is less active and sometimes territorial in habitat, the shape of the cage does not affect its mobility. In this case, design rectangular cages for easy assemblage and management. The arrangement of the cages is not a problem if there are only few of these. However, 8 or more should be arranged depending upon the direction of the wind.

There are many kinds of nets that could be used for cage fabrication. The most common are the B-net (1/4? mesh), DD-net (3/8? mesh) and CC-net (1/2# mesh). However, the most popular is the B-net because smaller fingerlings do not need a nursery cage. It is cheaper per unit area because it is wider (108 inches) than other nets, hence, labor cost in fabricating cages is much lower, and tearing of one or two meshes do not easily provide an escape route for bigger fish.

Generally, floating net fish cages are made of nylon nettings supported on all sides and corners with polyethelyne rope fixed by a nylon twine. Each is hung within a rectangular area, the top is supported by bamboo braces and the bottom is provided with lead sinkers. The size of net cages used in Magat Dam for commercial production of tilapia is 6 m deep, 6 m wide and 12 m long. This size makes possible the full utilization of bamboo poles and nets. To do it, hang the net cages in bamboo raft type frame which also serve as catwalk for workers allowing 1 m of the net above the water level and fix the synthetic ropes to four corners of the poles to prevent the fish from escaping by jumping out. The longest side of the cages is oriented perpendicular to the direction of the wind.

Construct the net fish cages in the following manner:

  1. Cut the net according to desired specification
  2. Double-lace every mesh of the four corners using nylon twine 210 d/6, double-twine beginning at the second mesh row using rolling hitch or clove hitch with a single hitch as lock at intervals of 7.62 - 10.16 cm.
  3. Double-lace the nylon salvage net to the top edges of the cage with a nylon twine, using either a rolling hitch or clove hitch with single hitch as lock. Start the second half from the second mesh row.
  4. Rig all sinkers (No. 7) to the rib lines of the bottom side and centers. Attach the rib lines on all sides using rolling or rib hitch with an interval of 7.62 - 10.16 cm.
  5. Make splices on the four corners of the hanging lines (top portion of net cage) for the attachment of four stretching ropes with weight. Continue with the other units following the same procedure.

Fish Stocking and Stocking Rate

Stock fish either early in the morning or late in the afternoon when the water is relatively cool. Acclimatize the fingerlings before stocking them. To do this, float bags of fingerlings in water where the fish is to be stocked, thereby allowing the water on the bags to float on the pond for 30 minutes. Determine the water temperature of both bag and pond waters with a thermometer. A difference of more than 30°C may cause eventual death of stock. Open the bags and introduce water gradually from the pond to the plastic bags until the temperature is almost the same. Let the fingerlings get out freely from the bags.

The number of fingerlings to be stocked in a cage varies from 10 - 15 pieces per cu m to reach a size of 100 g each in 150 days without supplementary feeding during summer months. Use the same density at the start of the rainy months up to early part of summer. However, the growth rate is lower during rainy months because the water is cooler and there is little presence of natural food in the water.

Management of Cages

Tilapia in cages requires minimal care and maintenance. Aside from occasional intrusion of predators, mechanical damage to the net screen and poaching, no serious problem can be expected.

Feeds and Feeding

Feeding of tilapia in cages is necessary for higher yield especially if productivity of the surrounding water is poor. Feed ingredients are locally available and economical. Supplementary feeds given to the fish using 3-5% body weight as basis for food ration per day. Divide the ration into 4 portions at an interval of 2 hours adjusted directly after sampling. Place feeds in small plastic bags. Weigh and label carefully according to the number of cages to avoid error when feeding.

Precautionary Measures

Before the onset of predictable bad weather, loosen anchor ropes and using a banca, tow all the units towards a sheltered area. Put additional anchors to strengthen the whole project units.

Maintenance of Support Facilities

Support facilities refer to the service "banca" raft, caretakers hut and other facilities in the project. The "banca" should always be in tip-top condition since this is the only available means of transporting the produce and for management personnel to supervise the project.
Protect plastic and pandan bags, styrofoam boxes, spare nylon net cages, nylon twine and other equipment from rodents. Repair leaking roof of huts to give ease and comfort to the project personnel.

Stock Manipulation

This is a scheduled monthly activity of grading the fish stock into different size groups to reduce the adverse effect of uneven growth and association of "size hierarchies" within the fish population. Smaller fish are harvested later when they reach the desired size and weight.
Most cage operators buy tilapia fingerlings of size 22 when high quality fingerlings are now readily available. These are not directly stocked in grow-out cages; instead, they are reared for about a month in cages with a mesh size of no. 24. After a month, grade the fingerlings and transfer the bigger ones in cages with mesh size no. 17. Repeat the process until they are stocked in cages with mesh size no .14 where they are reared up to marketable size. This technique of grading the fish, called modular method, enables the cage operator to stock and harvest the fish continuously.

Care and Maintenance of Cages

For daily and routine work, check loose twine and torn meshes of the nets and repair immediately by mending or patching. Remove by brushing bio-fouling organisms such as freshwater algae, sponges and debris that set on nylon net as soon as they detected. Replace the whole cage with spare net cage, when may fouling organisms had accumulated obstructing water exchange.

Check the net screen everyday for wear and tear as there might be possible damage that leads to the escape of the fish stock. Dive occasionally and inspect the condition of nettings and other materials submerged under water.

Harvesting/Post-Harvest

Before harvesting, prepare all the materials and equipment needed. Two to three persons can manage one fish cage.Untie the top corners of the net and allow the bamboo raft to enter the rectangular area. Two harvesters lift the net and push the raft toward an end of the cage. Scoop out the confined fish at one end of the net and place these in pails. Sort according to size. Place sorted fish in transport containers.

The need for proper handling and processing of tilapia is important both for the fishing industry and for the consumers.Improvement of the processing and handling of tilapia in terms of quality, product range and volume results in increased economic activity and employment. It is also one way of stabilizing fish marketing by providing an outlet for surplus and peak catch even during emergency harvest, thereby ensuring high fishing activities and stable prices. It can also contribute to the efforts related to nutritional goals.

Handling

The quality of fish depends on how it is handled from the time it is taken out from the water until it reaches the kitchen. Fish landed is usually subjected to rough handling treatments. Consider these 3 cardinal rules in handling fresh fish:

1. Cleanliness. Observe cleanliness throughout the fish handling chain. Clean the deck, checkboards and containers thoroughly before the fish haul comes aboard. Clear one haul away before the next ones come aboard. If you have to leave some fish on deck, move them at one side of the deck so that fresh fish are not placed on top of these.

2. Care. The fish you are handling is food, treat it as such.

  • Work on fish as quickly and as promptly as possible.
  • Sort fish properly before packing
  • When fish have to wait on deck or on the fish landing for some time before working on these, cover these to protect them from heat and other elements.
  • Drain fish before icing
  • Avoid brushing the fish
  • Don't throw, trample or kick the fish

3. Cooling. Temperature is the most important single factor affecting the quality of fish.

  • Use plenty of ice. Put additional layer of ice on top, bottom and side of fish in boxes or shelves
  • Don't over-fill a box or shelf. The next box or shelf on top will smash the fish below.
  • Lay the fish belly downward - this prevent entry of dirt water into the fish.
  • Don't pack fish so tightly that melted ice cannot flow.

Fish is cooled more quickly when ice cold water is poured on them. Fish spoils easily when allowed to stay in stagnant water, blood or slime. If the vessels is provide with fish room, store fish in ice as quickly as possible. Make sure the fish room is always kept clean.

Transporting

Fresh fish transported to far distances must be packed with ice to ensure freshness when they reach the consumers. Proper packing of fresh fish with ice means arranging the fish and ice alternately in the container to maintain 5°C chilling temperature is attained with the ratio of 1 kg of ice to 2 kg of fish. Fresh fish may be transported in styrofoam boxes, conical tubes (bañera) basket ("kaing"/"bayong") and plastic containers.

The more sophisticated method is the refrigerated truck.
When transporting tilapia within the region, wholesalers pack them in ice. Upon reaching their destination, fish are repacked with ice and sold to retailers and eventually to consumers.

Freshwater Fishpond

The success of freshwater fishpond farming depends on the selection of ideal fishpond site, proper planning and layout design, proper construction and appropriate pond management.

Considering the expenses involved in pond construction, freshwater fishponds smaller than half a hectare are not commercially viable. This technoguide is designed for freshwater fishponds with an area of one-half hectare or more.

Site Selection

Water supply

Water supply is the foremost factor to consider in selecting a fishpond site. The site must be accessible to adequate water supply throughout the year and free from pesticide contamination and pollution. Sources of water can be a surface runoff, stream, creek or irrigation.

Soil characteristics

Clay, clay loam, and sandy loam soils with deposits of organic matter of about 16% are best for fishponds. Hard mud of the above types are preferable to the soft and very loose kind. Avoid sandy, rocky or stony soils because these do not retain water in the ponds. Choose flat terrains for easier excavation and leveling. If the topography is to undulating, the construction costs increase greatly and excavation work removes the fertile portion of the pond bottom. Avoid sites that are frequently flooded.

Other factors to consider

Availability of quality fingerlings and cheap skilled labor, accessibility to market and peace and order condition.

Design and Layout

In designing and planning the layout of freshwater fishponds, give careful consideration to the following:

  1. Pond compartments. There are three compartments in a complete freshwater fishpond system namely: nursery pond, brood pond and production or rearing pond. The nursery and brood ponds may comprise 10% of the total area, and 90% for the production pond.
  2. Water supply. Provide each compartment with an individual water supply system and drainage outlet. Provide also a mechanical emergency spillway for the flow of excess water from ordinary rain and to maintain desired water level in the pond.
  3. Drainage. Construct the pond to facilitate easy drainage when harvesting fish stock and proper cleaning of the pond bottom.
  4. Elevation. Construct the pond one meter or more lower than the source of water supply but slightly higher than the drainage area to obtain at least an average water depth of one meter for maximum production.
  5. Wind direction. Wind plays a role in fishpond design. Strong wind generates wave action that destroys the sides of the dikes. To minimize this, position the longer pond dimensions parallel to the direction of the prevailing wind to lessen the side length of the dike exposed to wave action.
  6. Protection from flood. If the fish pond site is prone to flooding, construct a diversion canal along the perimeter dike to divert runoff water during heavy downpour. Construct a larger and higher perimeter dike to prevent inflow of water.

Designing dikes
Construct dikes with trapezoidal cross section with the top width, the side slopes and the height proportionally designed according to the soil material used. The following are guidelines in designing the dikes:

  1. Height above water line. Extend the top of the dike sufficiently above the water line to give a safe margin against overtopping during flood. Include margin for wave action caused by exposure to winds. Perimeter dike should have, after shrinkage, a freeboard height of 0.60 - 1.0 m above the maximum level observed in the locality. Freeboard for secondary dikes is 50 cm. The allowance for settlement and shrinkage depends on the characteristics of soil fill, soil foundation, and on the method of construction. On the average, an allowance for settlement and shrinkage is 25%. Provide a settlement allowance of not less than 40% for soils high in organic matter while dikes compacted by construction equipment is 5% less than the filled height.
  2. Top width. The minimum top width or crown is 1 m for dikes less than 3 m high. The top width of dikes used as access road is 4 m. Provide a 0.60 m wide berm or shoulder on each side of a roadway dike to prevent rovelling.
  3. Side Slope. The side slope or steepness of the dike is the ratio of the horizontal length to the vertical rise. Fishpond dikes lower than 3 m should have a slope of 1:1. Dikes above 3 m should adopt a 2:1 slope. Refer to the table below for relationship among the top width, bottom width and height of dikes.

Relationship among the top width, bottom width and height of dikes with a given side slope:

Construction of Pond System

Plan fishpond construction carefully and systematically. The system of pond construction is based on the prepared program and schedule of development.

Dike construction
Clear the dike site of vegetation, slumps and debris. Clear the strip 2-4 m wider than the base of the dike. For sites with decaying matters, construct a puddle trench at the center of the path of the dike. Excavate 0.5 m wide by 0.5 m deep trench filled with clay soil to prevent excessive seepage on the finished dike. Dig blocks of mud for construction of dike at least one meter from its base. Allow each layer to settle firmly before adding another layer until the desired height is attained. Construct dikes either manually, mechanically or both.

It is very important to have a uniform dike height. To do this, get a 50 m long transparent plastic hose. Fill the hose with water. Hold one end of the hose at the first station and the other end at the next 40 m away. If the water level at both ends are the same, the dike is level. Repeat the process until the last station has been marked.

Canal construction
Construct the canals simultaneously as the adjacent dikes. Stake markers to serve as guide during the excavation of canals. Slope the canal gently towards the drainage gate of pipe to keep the flow of water sluggish and to avoid excessive erosion.

Construction and Installation of Water Control Structures.
Water inlet or outlet structures are usually made of wood or concrete gates, galvanized iron sheets or reinforced concrete pipes.

Place 3 pairs of grooves on each side of wooden or concrete gates extending to the top of the dike where they are installed. The middle pair of grooves allows the removable slabs to regulate the flow of water. The first and third pairs enable the screens to prevent the escape of cultured fish. These screens may either be of bamboo splits or nylon attached to a wooden frame.

In freshwater fishponds, galvanized iron pipes or reinforced concrete pipes are often used instead of concrete wooden gates. The following is a guide in determining the proper pipe diameter to be installed.

Size of drain pipe in inches – Condition:

  • 4 - Can drain 1 ha. pond with average depth of 1 m in 6 days
  • 6 - Can drain the same in three days
  • 12 - Can drain the same in one day

With proper scheduling of draining time, it is adequate to use 4 to 6 inch pipe for one hectare pond and 6 to 11 inch pipe for larger ponds. Construct water supply and drainage system simultaneously with the dikes.

Pond Bottom Leveling
Mechanical leveling is cheaper and faster than manual leveling if the pond bottom can support the equipment used. Use farm tractors or tillers with a back blade. The carabao and the harrow may be used in small ponds. The pond bottom should slope gently towards the drainage gate to facilitate complete drainage.

After leveling the pond, plant creeping grasses at the dikes to prevent erosion. Plant bananas at the outside slope of the perimeter dike to serve as wind breakers. Do not plant trees along the dikes because the roots will cause leakage and seepage.

Pond Preparation

Prepare the ponds a month before stocking fish in the following manner:

Draining and drying.

Drain and dry the pond completely. Dry for about a week or more, depending upon the weather, until the bottom cracks or harden sufficiently to support a man on his feet without sinking more than 1 cm. Make sure the pond soil is dried every time the pond is harvested. Periodic drying stabilize soil colloids and oxidizes organic matters that encourage the growth of natural fish foods. Draining and drying eradicate competitor fishes and predators, and kill disease-causing organisms.

Cultivation of pond bottom.

Till or cultivate the pond bottom as soon as it is drained. Do this by stirring or cultivating with a shovel or a rake for small ponds. For large ponds, use a rotavator. Cultivation makes sub-surface nutrients available at the surface for the growth of fish food in the pond, eradicate burrowing predators like mudfish and eliminate undesirable pond weeds like "aragan."

Leveling.

Level the pond bottom after this is cultivated. Leveling makes the pond bottom slope gradually from its farthest end down towards the drainage structures - the deepest portion of the pond.

Repairing gates and screens.

Check all gates and pipes for broken slabs and other parts. Repair screens to prevent predators and pests from entering the pond system. Clean to remove debris which may cause clogging.

Repairing dikes.

Check all dikes for leakages and seepages. All dikes must be water-tight. Put a puddle trench excavated about 30 cm wide and 50 cm deep or more along the dike. Build this at the center of dike towards one side, or dig two puddle trenches at both sides of puddled trench long enough to cover the entire seepage and sufficiently deep to go beyond the general level of the pond floor. Fill the trench with new mud or soil. Allow the soil to settle well to give a firm line of earth.

Pests, Competition and Predator Control

Fish production in ponds is commonly affected by some pests and predators. Predators are organisms which prey on the cultured fish. Animals that compete for food or space are called competitors.

 

  1. Piscivorous or predatory fish and other competitors: Catfish (hito), mudfish (dalag) and gurami may enter ponds during floods or when accidentally stocked with the cultured fish. These predators devour fry and fingerlings during or after stocking. To avoid them, drain the pond totally after harvest or before stocking. Mudfish which tends to burrow into the mud, can be totally eliminated by using tobacco dust at the rate of 500 kg/ha. Screen water gates and outlets properly to prevent entry of unwanted fishes. Check fingerlings properly for any possible contamination by predatory fish prior to stocking. Competitors are associated with predators. Both compete with the stocked fish for space and food.
  2. Birds: Herons, kingfishers and other birds must be prevented from frequenting the ponds. They devour fish and fingerlings and are also carriers of parasites. Ponds constructed without shallow areas are not attractive to birds.
  3. Snakes: Snakes prey on small fish. Always keep banks and dikes clean to prevent snakes from harboring n the ponds.
  4. Frogs: Frogs eat fry and fingerlings. Tadpoles also compete with the fish for space and oxygen. Frogs are seldom found in well-fertilized and well-stocked ponds. Their population can be controlled by removing their egg sacks from the pond water.

Soil Conditioning

Soil acidity limits the production of natural fish food by decreasing the amount of plant nutrients and, in some extreme cases, kill fish. In cases where soil pH is below 7.0, it is important to control acidity to ensure high fish production.

Analyze pond soil at least once a year to determine its exact pH value. Soil analysis is especially recommended for newly constructed fishponds as basis for proper soil conditioning. Refer to Appendix D for proper collection of soil sample.

Methods of controlling and correcting acidity

  1. Leaching. Wash or flush the pond bottom to reduce acidity. This process is effective in slightly acidic soil.
  2. Liming. Apply lime in fishponds primarily as a soil conditioner. Liming corrects soil acidity, promotes the release of soil nutrients, precipitates suspended materials which hamper light penetration and reduces incidence of fish diseases.

Agricultural lime (CaCO3) is the most common time used in fishponds. Unslaked lime or quicklime (CaO) and slaked lime (Ca COH)2 or hydrated lime may also be applied. These are available on arrangement with agricultural input dealers.
Broadcast or spread the needed lime over the drained but moist pond bottom. Mix the lime, thoroughly with the soil to attain maximum effectiveness. Allow one week to lapse before applying phosphate fertilizer.

Fertilizer Application

Applying fertilizer in ponds to supply the nutrients needed for plant growth is a fundamental part of fishpond management. Fish production per unit area can be increased as much as five-fold by proper application of fertilizer. Fertilizers are classified into two groups:

1. Organic Fertilizer: The nutrients and organic matter content of manure increase the water holding capacity of the soil, decrease the rate of evaporation and increase enzymatic activity, all of which increase fertility and yield. Animal manures contain the major nutrient components such as nitrogen (N), phosphorous (P), and potassium (K), in addition to such trace elements as calcium (Ca), copper Cu) iron (Fe) and magnesium (Mg). Phosphorous comes mainly from feces except from swine manure which has more nitrogen and potassium. Animals fed with roughage ration excrete more potassium than those fed with high concentrate ratios.

The chemical composition of manure also varies depending upon the animals, nature and amount of manure and the handling and storage of the manure before use. The most common organic fertilizer used in fishponds are chicken dung, cattle manure and swine manure. Chicken manure may be utilized as fish feeds and at the same time helps create a soft mulch bottom to make a habitat for other food organisms. Compost, rice bran, and sewage may also be used.

2. Inorganic Fertilizer: These are chemical fertilizers containing concentrated amount of at least one of the three major plant nutrients: nitrogen, phosphorous, and potassium. The common fertilizers used in fishponds are Super phosphate (0-20-0), Monoammonium phosphate (16-20-0), and Diammonium phosphate (18-45-0).

Plankton Production

Tilapia consumes plankton as food. Plankton is responsible for producing greater fish weight than any other type of natural food raised in ponds.

Stocking of Fingerlings

Sources of Fingerling

High quality fingerlings ensure better profit in tilapia culture. Inferior tilapia fingerlings grow slowly and may not reach the desired marketable size of 85-100 grams in 4-5 months culture period. Fish-farmers should secure their initial stocks from reliable sources.

Time and Method of Stocking

The best time for stocking fingerlings in the pond is late afternoon or early morning. Before the fingerlings are released, ensure even temperature between the water in the plastic bags and the pond where these are to be stocked. If the difference in the temperature is more than 3°C, introduce water gradually from the pond to the plastic bags until the temperature is almost the same.

To stock, bring the plastic bag of fingerlings to the pond preferably near the gate which is supposed to be the deepest part of the pond. Bring down each bag to the pond and tilt towards one side to allow the pond water to flow gently into the bag. Allow the fish to swim out of the container voluntarily. One oxygenated plastic bag contains 300 fingerlings.

Fish Stocking Density

Fish stocking ratio is one of the several factors that affects fish growth. At low stocking density, the amount of natural food in the pond is higher for each individual fish and the excess food is not utilized. As long as other factors are not limiting, the growth of fish is not utilized. As long as other factors are not limiting, the growth of fish will be better. The maximum physiological growth of tilapia is attained at low stocking density.

A one-hectare pond with plankton can accommodate 10,000 to 20,000 fingerlings of nile tilapia measuring 3-4 cm. Supplemental feeding is necessary to have better produce.

The stocking density influence the inputs needed and yield of the fishpond. Failure to select the most appropriate stocking density results in poor growth and low market value of fish.

Water Management

The water should be free from toxic chemical contamination and unwanted predatory or wild fishes and must be available when needed. Employ precautionary measures when using water from rivers, streams and communal irrigation systems.
Maintain water depth from 70 to 100 cm to satisfy fish requirement for space and oxygen and to prevent over-heating of water during hot weather. Early breeding of tilapia results when water temperature highly fluctuates, as in the case of rice-fish paddies where tilapia are observed to breed earlier. To discourage early reproduction and to increase the growth rate of tilapia, maintain water depth at one meter in grow-out pond.
Employ some management modifications when water supply is seasonal. When using rainwater or irrigation water with limited flow, it is necessary to increase the volume of pond water by increasing depth if possible, store enough water in the pond during the rainy days.

Water Temperature

Tilapia nilotica can tolerate water temperature range of 14° - 42°C. However, for culture purposes, the ideal water temperature should range from 25°C to 30°C.

Hydrogen ion (pH) Concentration

The ideal pH range of freshwater culture is 6.5 - 9.0. The effect of the various pH value on fish is shown below:

Measure the pH with the use of litmus paper, pH comparator, portable pH meters or the Hach kit. In the absence of any of these equipment, tasting the water is a practical way to determine the pH. The water is acidic if it tastes sour and it tastes bitter, if it is alkaline.
Acidic water usually comes from swamps, bogs or water in stagnant areas. Liming and correct water management corrects pH in pond water.

Hydrogen Sulfide

This is a poisonous gas which evolves from the pond bottom as a result of decaying and decomposing organic matter. Its presence can be detected by a smell similar to that of a rotten hard boiled egg. Hydrogen sulfide in the pond causes mass mortality and small patches or hemorrhage in the gill region of the fish.

Eliminate hydrogen sulfide before stocking by draining and drying the pond for 1-2 weeks until the bottom cracks. If this is not possible, agitate the water with any gadget or by running pump-boats or introduce freshwater into the pond. Do not apply organic fertilizer until the smell disappears.

Ammonia
This is highly toxic to fish. the symptoms of ammonia toxicity in the fish are:

  • spongy appearance of gill filaments
  • presence of bloody gills
  • excessive production of slime
  • poor growth of fish

One of the most common causes of high ammonia level in ponds is the heavy application of manure. Organic matters increase the ammonia level during decomposition and overgrowth of plankton.

Dissolved
Tilapia species can grow well at dissolved oxygen level of 1 - 3 ppm.
Some causes of oxygen deficiency in ponds are plankton bloom, decaying or dead fish, and decomposed organic matter. Most prominent of these, however, is heavy application of organic fertilizer in ponds since decaying organic matter absorb oxygen and give off carbon dioxide.
Good water management prevents the occurrence of dissolved oxygen depletion. In order to maintain high dissolved oxygen level in the pond, do the following:

  1. Prevent the growth of unnecessary aquatic vegetation, such as "kangkong" over the pond surface.
  2. These plants shield the pond from sunlight and slow down photosynthetic activities of phytoplankton to produce oxygen.
  3. Follow the recommended stocking rate of the pond. Over-stocking leads to high oxygen consumption and possible oxygen depletion especially at night.
  4. Avoid giving excess feeds to the fish since unconsumed feeds pollute the pond water when they sink to the bottom and decay.
  5. Apply only the recommended fertilizer rates. Putting more than enough organic fertilizers result in dissolved oxygen depletion as a consequence of decomposing organic matter.

Turbidity
Turbidity can be either an advantage or a disadvantage in fish culture. It is advantageous if it is caused by plankton. However, if the water is turbid due to minute solid particles, then this becomes a disadvantage because the sediment particles prevent photosynthesis.

To solve turbidity problem, spread about 2-3 ton/ha or 200 grams/sq m of rice stalks or chopped hay on the pond bottom.

The simplest way to measure water transparency is by using a Secchi disc or one's hand. A Secchi disc is a white and black disc (about 30 cm in diameter) suspended from a calibrated rope (usually in centimeters) into the water. If the disc appears at the depth of 30-35 cm, the water is not turbid, but if it disappears within a depth less than 30 cm, the water is turbid. With the right arm stretch forward, slowly dip your hand into the water until the palm becomes invisible. Water transparency is expressed by the distance (cm) from the wet wrist to the end of the water mark on the arm.

Harvesting

For better regulation of fish density in ponds, employ harvesting methods that can efficiently remove most of the fish. A small number of fish left in the pond after harvest may be caught during the next harvest to allow the fish to grow larger. However, too many fish left in the pond may affect the growth rate of the fish stocked in the next production cycle. Harvest only sufficient number of stocks while allowing enough space for the remaining fish to grow.

Methods of Harvesting

  1. Thinning. Start harvesting partially in the later part of the growing season. Wild spawning normally occurs in this part of the culture period. When the fish reach maturity, thin the bigger fish in the pond to allow growth of the remaining fish stock. If thinning is done for marketing only, use a net that can catch the desired size of fish. In tilapia culture, thin only once. Harvest the fish totally one to two months after thinning.
  2. Seining. Although seining is often recommended in harvesting fish in the pond, it is not very effective in ensuring total harvesting of the stock. Tilapia often burrow themselves into the mud to escape from the net.
  3. Draining. Drain the pond to the half-level mark the night before harvesting. Catch larger fish with a 1? mesh sieve and place in a drum, suspension net or "hapa" or large buckets filled with clean water to wash away mud. To keep tilapia alive indefinitely, place these in cages or net enclosures in a pond with clear water. In case the fish has an earthy smell or taste, hold them for about two days in separate pond with flowing water to improve their taste.
  4. Catch the remaining fish by lowering the water level using a fine mesh sieve to collect the fingerlings. Transfer and keep the fingerlings alive in suspended net enclosures (hapa) installed in another pond. Do not overstock the fingerlings in the holding units to prevent heavy mortality. Sell or use these fingerlings for future stocking.
  5. Harvest only the exact amount of stocks that can be absorbed by the consumers at the specific time. There is risk in harvesting the stock in bulk without any formal or closed arrangement in the market.
  6. To eliminate undesirable predatory species and competitors, drain the pond completely. If needed, spray pesticides for total elimination of predators left. Expose the pond bottom to sunlight to increase its fertility.

Source: Department of Agriculture – Bureau of Agricultural Research, Date accessed 24 March 2014

Tomato

Description

tomatoTOMATO

TOMATO or Kamatis in Tagalog or tomato in English is classified as a vegetable. It is a tropical plant but often does not grow well under such conditions. It is a rich source of Vitamin C and a popular cash crop for small farmers and home gardeners.

Tomato is an important and popular vegetable grown in many parts of the world. The fruit is used as an ingredient in many food preparations and is regarded as one of the most profitable crops for off-season production, preferably from May to September.
(Source: Department of Agriculture- Bureau of Agricultural Research, Date accessed 24 March 2014)

For Cost and Returns, you may visit the Bureau of Agricultural Statistics.

For further assistance in your area, you may check the Technical and Financial Assistance Directory.

Cultural Management

 

Climatic and Soil Requirements

Site Selection

Choose a part of the farm that is slightly elevated and has good drainage to avoid water logging in case a flash flood occurs during the wet season. For dry season planting, make a catchment with a canal directed into it to drain excess water after each irrigation schedule. Choose a sandy loam or clay loam soil with a pH of 5.5-8.0.

Growing Season

Tomato can be grown anytime of the year. In hilly areas, plant tomato from September to January. For lowlands, plant from November to February. Grow off-season type and grafted tomatoes (kamlong) from May to September for bigger profit.

Land Preparation

With a carabao drawn implement, plow and harrow the area once and twice if the soil is not in good tilt. Then set furrows at a distance of 100 cm before transplanting the indeterminate type or semi-viny. For determinate type with bushy growth habit set at 75 cm distance between furrows.

Crop Establishment

There are two methods of seedling production: the use of seedbed and seedling trays.

Seedbed method

  1. For 1000 m2 tomato production, use one seedbed measuring 1 x 10 m so that seedlings will not be overcrowded, thereby producing seedlings with bigger stems. Cover the seedbed with 3-5 cm thick rice hull and then burn completely to minimize the incidence of pre-emergence damping-off on the seedlings.
  2. Mix 10 kg compost and 100 g complete fertilizer and incorporate these evenly into the seedbed. Sow the seeds in small shallow furrows at 20-30 g/10 m2. Cover the seeds lightly with fine soil. Dust the surroundings of the seedbed with Sevin SP to control ants, and spray 1 tbsp of Vitigran Blue per gallon of water to avoid infection of damping-off. To ensure uniform germination of the seeds, saturate the seedbed with water for the first three days using sprinkler until the seeds emerge.
  3. To avoid succulent stem, regulate watering as soon as the seedlings have emerged. For the seedlings to have a good start, apply urea at a rate of 1 tbsp/gal of water at 7-14 days after emergence (DAE). Sprinkle water on the seedlings using a sprinkler (regador) immediately after applying the fertilizer to avoid burning effect on the leaves. Drench the seedbeds with Vitigran Blue at the rate of 1 tbsp/gal of water once damping-off is observed.
  4. To produce hard seedlings, water the seedbed only when plants show temporary wilting (this can be observed in the morning) and repeat regularly starting at 14 DAE until the seedlings are ready for transplanting, which is at 25-30 DAE. Water the seedbeds thoroughly before pulling the seedlings for transplanting to minimize root damage.

Seedling tray method

  1. Seedling tray method (Fig. 2) needs only 100 g seeds/ha or 10 g for 1000 m2.
  2. Plant the seeds singly in each hole of the tray intended for seedlings with potting medium (Fig.2a) available at seed stores, or bake garden soil for 2 hours.
  3. When cooled, mix the garden soil, fine sand and compost at the ratio of 3:1:1. Drop 2-3 grains of 14-14-14 in each hole (Fig. 2b) before filling with the soil mixture.
  4. Care and maintenance of seedlings (Fig. 2c) is the same as in seedbed, but transplanting shock is minimized in tray method.

Transplanting

For wet season planting, use one month old seedlings because these are harder, taller, and can withstand the impact of rain. Transplant seedlings at a spacing of 0.50 m between hills and 1.0 m or 0.75 m on rows or furrow right after irrigation water run in the furrows. For dry season, transplant 25-day-old seedlings.

To avoid breaking the stem of seedlings during transplanting on irrigated furrows, hold the roots with the thumb and forefinger then push towards the soil at 3-5 cm deep depending on the length of the stem. For an area of 1000 m2, transplant the seedlings on the right side of the furrows for the first half of the area. For the next half, transplant on the left side of the furrows. For easier off-barring, use a carabao-drawn plow.

For seedlings in trays, transplant each seedling together with the soil medium from the tray using the same planting distance and method of transplanting as in seedbed method. If grafted tomato will be used, transplant the seedlings 3 cm deep to the hole and cover firmly with light soil. Do not cover the grafted part to avoid infection. Support the transplanted seedlings with trellis.

Nutrient Management

Broadcast chicken manure or organic fertilizer before land preparation or at final harrowing to fully incorporate the fertilizer into the soil. Apply 14-14-14 at transplanting so that seedlings will be healthy and vigorous before flowering. Delayed application will result in weaker plants and smaller fruits. Side dress using urea mixed with muriate of potash (0-0-60) for higher fruit setting, and to prolong the fruiting period of the crop.

Water Management

Four to five irrigations are needed from transplanting to 14 days before the last harvest depending on the type of soil. Tomato is very sensitive to flooding; hence, irrigation must be done just to moisten the root zone especially during the onset of flowering up to the last harvest.

The following irrigation schedule must be followed for a 1000 m2 area:

  1. First : during transplanting (flooding) or hand watering
  2. Second : 14 DAT (flooding) or hand watering
  3. Third : at vegetative stage (21 DAT), water at 1 L/hill.
  4. Fourth : at flowering and early fruiting (30 DAT) water at 1 L/hill.
  5. Fifth : optional, depending on the appearance of the plants at harvesting stage (hand water if necessary)

Pest and Disease Management

Insect pests and diseases of tomato are managed by using chemical, biological, and remedial measures. Most of the pests and diseases of tomato are common throughout the year except thrips and whiteflies, which are present only during dry season starting in January, declining in May and ending in June or July depending on the arrival of rain. The farmer or any amateur grower may try the suggested biological and remedial measures in managing the insect pests and diseases. In case of pest outbreaks, the use of chemical pesticides is the last resort.

 Insect Pest and DiseasesSuggested Management

Insect pest:

Fruitworms/Cutworms

To control worms at fruiting stage, spray neem seed extract at 200-300 ml/16 L or hot pepper fruit extract 100-200 ml/16 L. For cutworm, spray before twilight.

Spray with Thuricide HP or Dipel (Bacillus thuringiensis) following manufacturers recommended dosage. These are bacterial pesticides

28 Spotted Beatle, Mites,

Leafhoppers, Whitefle/Thrips

To drove other pests spray 100-200 ml pure tubai leaf extract/16 L of water on the plants alternate it with spraying karot tuber extract (100-200 ml tuber extract per 16 L water). Do it twice a week.

Puff smoke on the crop twice a week during the whole growing period.

For thrips, mites, leafhopper and white fly, practice overhead irrigation.

For thrips use blue sticky trap, for whitefly use yellow sticky trap.

Diseases:

Leaf spot

To control these disease spray the leaves with zinc oxide power at 2-3 tbsp/16 L water (with 1 tbsp sticker during wet season). Spray decoction of serpentina 10ml extract per 16 L water.

Fungal wilt/Bacterial wilt

Treat the seeds with Centella asiatica (takip kuhol) decoction at 45°C to 50 °C for 2-5 minutes. Uproot infected plants and burn outside the area. Drench infected soil with 5% solution of zonrox then expose to sunlight. Avoid surface irrigation. Do not cultivate or touch infected plants as this will transfer the pathogens to other plants. If possible, hand water the plants early in the morning or late in the afternoon with 1 L/plant every week at vegetative stage and 2 L/plant every two weeks at fruiting stage for clay loam soil.

Bacterial spot

To prevent this disease, spray a decoction of guava, star apple and avocado (done by boiling 1 kg leaves of each in 3 gallons of water for 5 minutes). For stronger concentration, restore 1 gallon decoction to 16 L water with 1 tbsp sticker. Spray on leaves and fruits of tomato once a week.

Minimal infection if grown after rice. Practice good drainage and use large dose of organic manure.

Powdery mildew

Spray Cassia alata (Andadasi or Acapulco) leaf extract at the rate of 1 L leaf extract/16 L water with sticker then spray vigorously on leaves and whole plants. For severe infection, spray a ratio of 1:1 leaf extract to water twice a week until the fruiting stage. As a disinfectant and as a preventive measure, spray 16 ml zonrox per/6 L of water or 1tbsp baking soda/16 L of water on the whole plant once a week.

Leaf mold

Burn infected plant residues after harvest. Plant tomato after rice and plant other crops after tomato (crop rotation). Plant resistant varieties.

Nematode

Plant 1 month old marigold seedlings as intercrop two weeks before transplanting of tomato. Plant resistant varieties.

Early Blight

Spray Acapulco leaf extract.

Late Blight

Spray Acapulco leaf extract alternate with serpentine decoction.

Blossom rot

Spray the plants with nutrients high in calcium at flowering stage. Or spray the plant with fresh malunggay leaf extract at a ratio of 1:4 malunggay extract to water. Or spray with decoction of seaweeds, decoction of burned sea shells, crabs and shrimps skeletons (1:10 shells to water).

Sources: Colting, L. M., et al, 2003; Farmers'/Gardeners' Practices

Chemical Control of Insect Pests and Diseases of Tomato

 Insect Pests and DiseasesSuggested Pesticides Rate Application (tbsp/16 L water)When and How to Apply
 Common NameProduct Name   
 Insect Pests    

Aphid

Methomyl

Lannette 40 SP

4.0 - 8.0

Spray any of the insecticides as soon as insect infestation is observed. Repeat spraying at 7-10 days interval or depending on level of insect population.

28 Spotted Beetle

Carbaryl

Sevin 85 S

4.0 - 6.0

 Spray any of the insecticides as soon as insect infestation is observed. Repeat spraying at 7-10 days interval or depending on level of insect population.

Thrips

Carbaryl

Provin 85 WP

4.0 - 6.0

Spray any of the insecticides as soon as insect infestation is observed. Repeat spraying at 7-10 days interval or depending on level of insect population.

Fruitworm

Methomyl

Deltametrin

Lambdacyhalothrin

Carbaryl

Lannate 40 SP

Decis R

Karate 2.5 EC

Provin 85 WP

4.0 - 8.0

1.5 - 2.5

1.0 - 1.5

4.0 - 6.0

Spray any of the insecticides as soon as insect infestation is observed. Repeat spraying at 7-10 days interval or depending on level of insect population.

Whiteflies

Thiamethoxan

Triazophos

Actara 25 WG

Hercules

1.5 - 2.0

4.0 - 6.0

Spray as soon as symptoms are observed. Repeat at 7-10 days depending on level of infection.

 Diseases    

Powdery mildew, Early & late blight/Leaf spot

Chlorathalonil

Mancozeb

Metalaxyl

Daconil 75 WP

Dithane M-45

Ridomil MZ 58 WP

4.0 - 6.0

4.0 - 6.0

6.0 - 10.0

Spray as soon as symptoms are observed. Repeat at 7-10 days depending on level of infection.

Bacterial Spot

Bacterial Wilt

Copper oxychloride

Vitigran Blue 35 WP

4.0 - 6.0

Spray when the first cluster is well formed. Repeat if required. Treat the seeds with 5% lime solution than subject to 50°C for two hours; air dry the seeds before sowing.

Source: Gajete, T.D. et. al 2004

Weeding

By using a carabao-drawn plow or hand hoe, cultivate in between rows of plants by off barring at 14-21 DAT. Hill-up at 28-35 DAT. Spot-weed at the surrounding of the seedlings after each off-barring and hilling-up if there are standing weeds. If plastic mulch is available, mulch the area before transplanting.

Harvesting

Harvest fruits intended for future use at matured green stage at 1-2 months during rainy season. Matured green fruits gradually ripen in one month at room temperature. Frequent harvesting sustains the production of more fruits. For immediate use, harvest the fruits at breaker pink stage. These will fully ripen within three days at ambient temperature but can be slowed when stored in a refrigerated condition.

Source: Department of Agriculture- Bureau of Agricultural Research, Date accessed 24 March 2014

Ubi/Yam

Description

yamUBI/YAM

Ubi (Dioscorea alata L.) or yam is a vine which produces both aerial tubers called bulbils and underground tubers or roots. The bulbils weighing a few grams and to over a kilogram come out from the leaf axils three (3) months after planting. The underground tubers weighing one to six kilograms can be harvested six months after planting.

The ubi roots has 70 percent moisture and 28 percent starch. It also contains traces of fats, crude protein, sugar, crude fiber, ash and Vitamin C, B1 and B2.

Ubi is grown primarily for its roots or tubers. The tubers can be eaten boiled, baked, roasted, flakes, chips and can be processed into powder form. Dehydrated yam slices are used for the preparation of food such as ice cream, cakes, pastries and other dessert. The ubi skin or peeling can be used as a raw material for the manufacture of food coloring.
(Source: Department of Agriculture- Bureau of Agricultural Research, Date accessed 24 March 2014)

For further assistance in your area, you may check the Technical and Financial Assistance Directory.

Cultural Management

 

Land Preparation

  • Tillage - Two plowings and two harrowings are usually enough for ubi for a field that has been previously cultivated. Plow deeply. Ubi needs a deep loose soil. Harrow along and across the length of the field to pulverize the soil.
  • Seedbed - Plant ubi on flat or ridged seedbeds. These are preferable to other types of seedbeds;
  • If flat beds are used, plant after the last harrowing.
  • On sloping or rolling fields, contour the ridges to minimize soil erosion.

Crop Establishment

Setts Preparation

About 20,000 to 27,778 setts are needed for a hectare of land. There are four types of setts: head, middle, tail and whole. The first three are prepared by cutting large tubers into pieces. The fourth type refers to the whole small tuber. Setts should be obtained from healthy tubers of healthy plants.

Slice large tubers into setts weighing from 60g to 250g. Do not slice tubers weighing less than 60g. Be sure that each setts has enough skin area. Treat cut sides of setts with ash or fungicide. Air or sun-dry the setts until cuts are dry. After drying, setts maybe pre-sprouted or planted directly.

Pre-sprouting setts


Sprouts emerge from setts about 2-3 weeks after planting. Pre-sprouting the setts before planting is recommended to minimize weeding expenses before sprout emergence.For a pre-sprouting bed, dig a shallow ditch in a shady area or clear the ground in a shady area by removing stones, weeds and debris.

Plant setts cut from large tubers either skin up or skin sideways. Whole tubers measuring 60 to 250g either crown up or crown side ways should be planted. Then cover the setts with a thin layer of soil. Water the pre-sprouting bed at least one a week until most of the setts have sprouted.

Preparing Pre-sprouted Setts for Planting

With pre-sprouted setts, planting may either be staggered or done at one time.

  1. Staggered Planting

The following activities must be performed in all batches of planting:

    1. Remove from pre-sprouting bed setts that have emerged to prevent sprouts from growing too long.
    2. o prevent sprouts from growing too long.
    3. Repeat the process every week or every two weeks until the desired number of sprouted setts for one batch of planting is obtained. Plant before the sprouts become too long to transport or before sprouts start wilting.
  1. One-time Planting

The procedure of sett preparation is essentially the same as that fro staggered planting. One-time planting is done only after most of the viable setts have produced sprouts. At this time, sprouts of some setts are already very long. Cut along sprouts before transporting setts to the field for planting.

Planting

Planting is done from March to June. However, planting time for ubi depends upon the time tuber dormancy is broken and the start of rain in the area.

Non-sprouted Setts
Plant setts in the seedbed at a distance of 1m x 50cm or 60cm x 60cm. Plant the setts 10cm deep during the rainy season and 15cm during dry season, especially if the field will not be mulched. Setts can be planted in any position

Pre-sprouted Setts
Plant the setts at the start of rain if it is not possible to irrigate or mulch the field. Plant the setts in the seedbed at a depth of 10cm and a distance of 1m x 50cm or 60cm x 60cm. Be sure to orient the sprout upward in planting. Divide the field into four to six section and if staggered planting is applied. Each section is intended for one planting batch. The size and the time to prepare each section depend upon the rate of sett sprouting.

Mulching and Weeding

Mulch the field to reduce soil temperature, conserve soil moisture, increase organic matter content of the soil and suppress weed growth.

Use dry coconut fronds, corn stalks, rice straw and other similar materials in mulching. See to it that these materials are free from weed seeds. Mulch the field just after planting. Make the mulch thick if rice straw or any material that rot easily are used.

With non-sprouted setts and without mulching, 3-5 weedings are needed. With pre-sprouted setts and with mulching, only two weedings at 2-month intervals are needed.

While plants are still short and unstaked or if the stake set-up allows, use animal- drawn implements to control weeds in an unmulched fields. Vines crossing the path of the animal should be lifted and placed along the rows before plowing.

Use handtools to weed the field once plants are already staked and the stake set-up does not allow the use of animal-drawn implement or if the field is mulched.

With non-presprouted setts and without mulching pre-emergence herbicides applied within one week after planting, maybe used to control weeds.

Staking and Training Vines

Place a stake for each plant before vines start crawling on the ground. Stakes should be 1-2m long. Bamboo, wood, cassava stalks, talahib stalks, or any similar materials that can support the ubi vines which can be used as stakes for at least seven months. If cassava stalk is used, it should be set up in an inverted position (young end down) to prevent the stalk from producing new shoots.

Ubi vines twines to the right. When vines start trailing on the ground, train the vines climb their respective stakes. Also, train the vines again when branches start crossing the rows, especially when weeding and hilling-up operations by using animal-drawn implements.

Nutrient Management

A hectare of ubi can remove about 128 kg nitrogen, 17kg phosphorus and 162 kg potassium from the soil. Collect soil samples from the field first before applying fertilizer and submit for soil analysis to the Bureau of Soils and Water Management.

Inorganic Fertilization - The recommended amount of fertilizer should be split into two, one half to be applied about one month after emergence (or one month after planting of pre-sprouted setts) and the other half about 2 months after the first application. Apply the fertilizer following the band method and placing the fertilizer about 10 cm away from the plants.

Organic Fertilization - Use of compost which is a mixture of decayed organic matter from plant parts and animal manure. Mix the compost with the soil during land preparation or place the compost just below the setts during the planting.

Harvest Management

Ubi is ready for harvest when its foliage is already yellowing or drying up. For most varieties, the drying up period of the foliage starts in late November and lasts until January the following year. Tubers intended for sett production should be harvested at the later part of the drying up period. However, tubers for consumption or for selling in the market should be harvested earlier, even before foliages dries up.

Harvesting ubi in sandy soil, use sturdy sticks sharpened at one end to dig out the tuber, remove soil particles that cling to the tuber and cut the vine at the base. For clayey and varieties with deeply buried tubers, use ubi harvester developed by the Philippine Rootcrops Research Training Center.

Prior to transporting, separate healthy tubers from diseased ones. Tubers should be arranged in a container in such a way that rubbing of tubers inside the container can be prevented. Place tubers in rattan baskets or in bamboo or wooden crates lined with soft material such as paper, banana leaves or straw. Arrange 2-4 layers of tubers in the container, the bigger the tubers the fewer the number of layers. Place soft material between layers and between tubers in a layer to serve as cushion.

Storage:

Tubers need to be stored in a bam while they are not yet marketed nor consumed whereas tubers intended for setts need to be stored until planting or replanting time. Storage structure for ubi should be shaded and adequately ventilated. There are three methods of storage:

  1. Barn storage - tubers are tied to vertically arranged poles held together by sturdy horizontal poles. Durable tying materials like rope are used in tying the tubers to the poles. The vertical poles are arranged about 50cm apart.
  2. Platform storage - large tubers are placed in one layer on raised platforms constructed in the shed. Small tubers are arranged in 2-3 layers.
  3. Shelf Storage - Tubers are placed on several decks of platforms instead of just one deck.

Source: Department of Agriculture- Bureau of Agricultural Research, Date accessed 24 March 2014

Watermelon

Description

watermelonWATERMELON

Watermelon, commonly known as "pakwan" inTagalog, is probably native to Africa. It is mainly eaten as dessert fruit. The rind is made into preserves and pickles; the seeds are processed into butong pakwan. In 1982-83, the area planted to watermelon was 15,410 hectares with a total production of 75,650 metric tons of fruits; but area was reduced to 5,370 hectares in 1983-1984 and production went down to 57,000 metric tons of fruits. The demand for watermelon could go up as freign markets like the USA offered to buy all the watermelon the country can produce.

Planting season is from October to January. In some parts of the country, planting is done as early as August to produce an off-season crop which commands better market price.(Source: Pinoyagribusiness.com, Date accessed 20 March 2014)

By-Products

  • Watermelon Seeds

For Cost and Returns, you may visit the Bureau of Agricultural Statistics.

For further assistance in your area, you may check the Technical and Financial Assistance Directory.

 

Cultural Management

Land Preparation and Planting

Watermelon prefers a well-drained sandy loam soil rich in organic matter and which has not been previously planted to watermelon. Watermelon requires more aeration than any other kind of crops, so the field must have good drainage to obtain good yield. In areas where growing season is short, light soil is desirable for early harvest. It grows satisfactorily in heavier soil if properly cared and managed.

Watermelon is tolerant to a wide range of soil acidity with soil pH 5.0 to 6.8 to successful growth. Along period of warm, preferably dry weather contributes to growth. A temperature of 25oC to 30oC is ideal for growth and 25o C is the best temperature for fruit setting.

Plow land at least 20 cm deep to increase soil aeration. Plow and harrow 2-3 times for early growth and development. These are done several weeks in advance of planting to condition soil. Though this is quite expensive, labor cost of weeding will be reduced.

Watermelon is grown from seeds directly planted in the field. Plant 3-4 seeds to a hill, 2.5 cm deep. Distance of planting ranges from 1.5 x 1.5 to 2.5 x 2.5 meters apart, depending on variety
After plants are well-established, thin to one to two plants per hill. Alternate plant is planting in continuous rows and thinning the plant to a distance of 1.5 to 2.0 meters. When plants have 3-4 leaves, thin to one plant per hill.

Fertilization

Watermelon is generally grown in rotation with other crops; it is necessary to use manure or any soil- improving crop to maintain organic matter in the soil. Apply 10 to 15 tons of manure per hectare. Apply complete fertilizer at the rate of 100 to 150 kilogams per hectare at planting time by hand placement 5 to 8 cm below the soil and 5 to 6 cm away to the side where seeds are placed. If plants show signs of yellowing, apply side dressing or nitrogenous fertilizer.
Watermelon has a spreading, hairy, tendril-bearing vines reaching 3-5 meters long. Leaves are oblong- ovate 8-20cm long with 3-7 lobes. Flowers are monoecious, yellow in color and about 2 cm in diameter.
Fruits are large, green-mottled or deep green. Introduced hybrids and varieties produce much bigger fruits, shapes varying from globular to oblong.

Cultivation

Cultivate and weed to check weed growth. Any implement may be used for the purpose. Avoid injury to roots while cultivating.
Watermelon may suffer injury when exposed to a long period of drought.Apply irrigation water when necessary. Frequent right irrigation 5-6 times during growing season is beneficial. During early stage of growth, irrigate sparingly since too much water tends to hinder root development

Pest and Disease Management

  • Cucurbit beetle- Adults are yellow beetle 6 to 8 mm in length. They eat leaves of young and old plants.
  • Aphids- Adults and young are tiny, greenish insects generaly wingless and soft-bodied. Insects suck the sap of leaves. Infested plants show curling and distorting of leaves.
  • Mites- Very tiny insects usually found on undersurface of leaves. Adults are reddish in color.
  • Downy Mildew- Caused by Pseudiperonospora cubensis Berk and Curt. Characterized by the presence of yellow spots on upper surface of leaves and purplish powdery material on lower surface.

Treat the watermelon seeds with appropriate fungicides to minimize early development of diseases in the field.
Dust or spray the young plants regularly with any suitable insecticides as soon as the false leaves have spread. At the seedling stage, watermelon are easily attacked by insect pests.


Harvest and Post-harvesting

Harvest watermelon fruits when mature enough to be sweet. Generally, it takes a watermelon fruit to mature 35 to 40 days from pollination depending on the variety. The old method of determining maturity of watermelon is by "thumping" with a finger. a dull or hollow sound is an indication of maturity.

The most practical index, However, is when the color of the lower part of the fruit that rests on the ground changes from white to creamy yellow. Harvest fruit with a sharp knife.

Pile newly harvested fruits in shaded areas. Do not bruise fruits during sorting, packing and shipping.

Source: Pinoyagribusiness.com, Date accessed 20 March 2014