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close this bookWorkshop to Produce an Information Kit on Farmer-proven. Integrated Agriculture-aquaculture Technologies (IIRR, 1992, 119 p.)
close this folderRice-fish systems
View the document(introduction...)
View the documentLow-input rice-fish farming system in irrigated areas in Malaysia
View the documentRice-fish systems in Indonesia
View the documentSawah Tambak rice-fish system in Indonesia
View the documentRice-fish systems in China
View the documentRice-fish system in Guimba, Hueva Ecija, Philippines
View the documentThe case of rice-fish farmer mang isko,dasmarinas, cavite, the Philippines


Low-input rice-fish farming system in irrigated areas in Malaysia

Rice-fish farming system is an old tradition, practiced extensively in the North Kerian Area of Perak, Peninsula Malaysia. The area is an alluvial coastal flood plain and receives irrigated water from the Tasik Merah reservoir. The soil is primarily clay with some acidity problems. Rice is double-cropped and short season high - yielding rice varieties are used.


There are approximately 352,000 ha or rice fields in Peninsula Malaysia, out of which 120,000 ha (34%) have sufficient water depth (15-16 cm.) for rice-fish system.


· The system, which is essentially wild fish ranching, requires little labor and material inputs. Fish from the irrigation canals, ditches and rice fields are trapped early in the rice-growing season, grown together with rice, and later harvested at the end of the season.



Rice field sizes vary from 0.81 to 1.42 ha. A sump pond, which can also be a disused well or borrow pit, ranging in size from 6.5 to 8.0 m diameter, is located at the lowest part of the field. Sump pond, which is cooler and has higher dissolved oxygen content, provides shelter for fish during periods of low water level. Perimeter trenches (0.25 m wide and 0.1 m deep) may be dug around the field to enable fish to move to and from the sump pond. These open trenches also act as feeding areas for fish to feed upon zooplankton especially during the fry and fingerling stages when zooplankton is important for early growth. Mud obtained from digging the trenches is used to strengthen the dikes (0.3 m high) around the field.

Farm layout option 1

Farm layout option 2

· No supplementary feeding is provided. Fish obtain food from natural sources in the rice fields. The system fertility depends on rice fertilization which is applied twice during the growing season. Urea (46% N) and NPK (17.5-15.5-10.0) fertilizers are used at the rate of 56 and 112 kg/ha, respectively. To further increase productivity and food availability, liming of the sump pond (if required) and manuring (if available) should be done.

Material Flow option 1

Material Flow option 2


Local species

Local species grow well in rice fields. They have adapted to the shallow water, high turbidity and temperature and low dissolved oxygen conditions of the fields.

· The snakeskin goramy (Trichogasterpectoralis) is numerically the most important. This species and the three-spot goramy (T. trichopterus) are herbivore/plankton and occupy the lower rung in the food chain.

· Climbing perch (Anabas testudineus) is an insectivore.

· The catfish (Clarias macrocephalus), an omnivore, and the mudtish or snakehead (Channa strata), a camivore, are also important species.
Newly considered speclea

· Tilapia (Oreochromis spp), a herbirore/plantivore/insectivore, is ecologically suitable and economically important.

· Other species to be considered is the freshwater prawn (Macrobrachium rosenbergi).

Calendar 0P activities

During fallow season, sump pond should be depend once every five years to about 1.5 - 2.0 m deep. Perimeter trenches (0.25 m wide 'D'; & 0.1 m deep) should be dug. Dike should be raised about 0 0:4 m, liming if needed should be done and manure available should be applied

Once water is available field repartition should be done by cutting raking and removing dead woods In about 7-10 days all exits should be blocked to prevent fish from escaping.

Transplanting of rice darlings weeding should be done especially in the trenches to provide feeding area (on plantation) for young fish

First fertilization add 5.6 kg/Ha furadan (carbofuran) mixed with urea (56 kg/Ha) and NPK (112 kg/Ha). Second fertilization after 60-60 days as above

Check the richfield as WELL AS the FISH. stop ALL leakage’s to prevent fish from escaping

When rice is about reads to be harvested drain the pond to harvest the fish. Take only marketable size fish (size depends on market demand) leave smaller fish as stoke for next seasons

Seasonal calendar


· Fish sales provide an important supplementary income especially to tenant farmers. Contribution from fish are 6.8 and 9.0 percent for owner and tenant farmers, respectively. Since little inputs are involved, the yields contribute significantly to farmers seasonal income.

· Fish are sold to dealers who provide pump, nets and other accessories needed to harvest fish. Small fish are left behind as stock for the next growing season. Marketable size fish are: snakeskin goramy 14 cm, catfish 20 cm and snakehead 25 cm.

Estimated range of potential yields obtainable from traditional & low input systems

* Option I traditional system

Option II improvements - building trenches, deepening sump ponds improving dikes, manuring and liming of sump ponds.

** include small-sized fish which are left behind for future stocks and climbing perch which is consumed or salted as "pekasam" and sold, potential

Estimated simplified budgets for the two systems.



Option I

Option II

Option I

Option II

Yields (ranges)

Cash from fish sales





Cash from "pekasam"

Sales (4-6 kg. x 5-6 kg/season - 2.00/1<9.)





Non-cash (domestic consumption -mostly snakeskin goramy 10-20 kg/season












Fixing dikes, trenches and sump pond and other mgt. act (4.5 day x us$ 4-00)



· Manure (12.5 kg x US$0.80)



· Lime (8.5 kg x US$ 0.80)






(a - b)





*Notice how in the first season, Option I has no initial costs and thus a higher net income than System II.

** However, in the second season, the costs for Option II go down and farmer gets a higher return compared to Option I.


· Short growing season due to double cropping of rice
· Improper and excessive pesticides and herbicides' use
· Uncontrolled flooding may result to fish loss.
· No proper management/lack of manpower
· Low productivity and low-carrying capacity since no regular supplementary feeding is provided
· Distance of sump pond from house
· Conflicting government program in the form of subsidy for rice.


· Provides additional food and income

· No additional expenses, except when system is modified, such as building trenches, strengthening dikes, etc.

· No major changes in normal farm practices; modifications to improve yields are adapted to the traditional practices by farmers if affordable. The no-improvement system (option 1) is sustainable for limited labor/older couple situations.

· Optimizes disuse and underutilized existing resources

· Maintains gene pool for locally valuable species.

Rice-fish systems in Indonesia

Rice-fish farming has a long history in Indonesia. In general, farmers have developed the systems that are now existing. The widely practiced rice-fish systems in irrigated areas of West Java are: minapadl, penyelang and fish palawija A special system called sawak tambak also exists in the coastal areas of East Java.

Rice-fish systems in Indonesia

Fish produced from ricefields are mostly seed fish for restocking in grow out systems, such as floating net and bamboo cages, running water (concrete tanks) and irrigation canal systems.

Minapadi system

Rice Agronomy

Rice varieties which are proven to yield high with fish during wet season such as IR 64 and during dry season such as Cillwung are planted. Planting distance in a thoroughly prepared land is 20 x 20 cm, 22 x 22 cm or 25 x 25 cm. In West Java, fertilizers used (and their rates of application in kg/ha) are: urea,200; triple superphosphate,100; potassium chloride, 100; and ammonium sulfate, 50. Water level is kept low during the filleting stage of rice. It is gradually raised to 10-15 cm throughout the rice growth.

Fish Culture

Common carp weighing 15-25 9 are stocked at 2,500-3,000/ha 7-10 days after rice planting. A center or cross-trench occupies about 2% of the total rice field area. Harvesting is done by draining the field slowly after a culture period of 40-60 days. Within this period, the fish attain 50-100 9, the size desired for stocking cages and running water culture systems.

Penyelang system

This is the culture of fish in between the first and second rice crops. Fish culture period is shorter than palawija system. A portion of the ricefield with rice stubbles is immediately stocked with common carp, while preparing the remaining portion for the dry season rice crop.

Stocking size varies: 5-8 or 8-12 cm or 15-25 9, depending on availability. Stocking rate is 2,0004,000/ha. Water depth is 10-20 cm. Fish are harvested after 30-40 days. This short period may not produce the desired size for growout in cages and running water systems, especially if stocked small. However, growout operators also buy small fish seeds if supply is scarce. The unsold small fish are restocked in the following dry season crop.

Penyelang system

Rice-fish cropping pattern in sawah tamak



Sawah Tambak rice-fish system in Indonesia

Literally, sawah tambak means ricefield pond (bracitishwater). However, this term refers here to the 12,152 ha rice-fish farm area in East Java which involves 15,000 households. Depending on the depth of floodwater in each area and fish or rice culture intensity, the sawah tambak rice-fish systems can be classified into the following:

System in Indonesia

1. Concurrent rice-fish system during wet season: appropriate in areas where inundation and the risk against submergence of rice is low. On the other hand, water is not sufficient to support a dry season rice crop.

2. Concurrent rice-fish (wet season) followed by dry season rice: done in areas where standing water is not so deep and water is sufficient to support dry season rice crop.

3. Fish culture (no rice) in wet season followed by dry season rice: appropriate in areas where flooding is deep.

4. Fish culture throughout: done in areas where farmers prefer to raise fish instead of rice in the entire flooding season.


Field Components

1. Peripheral dike. This is built by excavating the inner peripheral canal of the field. base width: 4-5 m; top width: 2-2.2 m; height: 1.4 - 1.8 m

2. Peripheral canal/trench. This serves as a fish refuge, nursery, holding/transition place, catching canal, and source of water for dry season rice. bottom width: 2 - 4 m; top width: 2.8 - 3.2 m; depth: 0.3 - 0.7 m

3. Ricefield area. The area used for planting rice is surrounded by a temporary bund 0.5 m high. This retains the water required by rice for its growth. The bund is also needed especially in concurrent ricefish '' system. sketch of A typical SAWAN tambak sketch OF holding place

Sketch a typical sawah tambak

Sketch a typical sawah tambak (transection)

Water Supply

Water comes from rainfall or seepage. Thus, there is no need to provide water inlet or outlet gates. When it is necessary to reduce or add water, pumping or boiling out water by the traditional method is used.

Prevention of Fish Escape During Floods

Farmers have ready grasses, plant leaves and similar materials to spread on top of dikes when flooks overtop dikes.

Preparation of Ricefield Area

The ricefield enclosed by the dikes is prepared just like an ordinary ricefield. Land preparation begins in September just before the onset of the rainy season, either by dry or wet method.

Nursery/Holding and Transition Area

These are constructed in the peripheral canal. The nursery is 10 m long, 5 m wide and 0.75 m deep. Water filling from outside is done through pumping or by traditional method. Fry stocking is done 2-3 days after water filling.

Oftentimes, prior to stocking fish in the entire sawah tambak, the milkfish and tawes fry are cultured separately in nursery/holding corner in the peripheral canal. The milkfish (stocking rate: 500/sq m) are raised here up to 45-60 days. The tawes (220/sq m) are kept at the holding place (with about 50 cm water depth) for one month before releasing them into the field.


Organic (compost, animal manure, green aquatic plants, etc.) and inorganic (urea and trisuperphosphate) fertilizers are applied The application rates are:


Rice hay


Plant leaves


Green aquatic plants


Urea is applied at the rate of 100-150 kg/ha/yr. and trisuperphosphate is 300-450 kg/ha/yr.

The total amount of urea and trisupemhosphate is each divided into three equal parts and applied thrice. As an example, the first application is a mixture of 25-50 kg/ha urea and 100-150 kg/ha trisuperphosphate.

Cultural Management and Harvesting

Combination of milk fish (Chanos chanos) and tawes or silver barb (Puntius gonlonotus) are stocked. Common carp is also added if available Stocking sizes and rate are as follows:

Stocking rate/ha




5-7 cm

5,500 -






cm 5,500 -


Culture period is 4-7 months, depending on the available standing water. In areas with deep water, culture period extends to one year. Stocking of fish can be done more than once. Harvesting is done twice or thrice. With no feeding, yield is about 2,000 - 3,500 kg/ha.


Immediately after the harvest of the dry season rice crop, dikes are raised by using a hoe, to contain water depth of 30-40 cm. The stocking size and rate vary. in West Java, common carp of size 3-5 or 5-8 cm are stocked at 5,000/ha without feeding. In North Sumatra, consumption size is produced in palawija system. The usual sizes stocked are 30-50 9 or 50-100 9 at the rate of 1,000-1,500 (no feeding); and 1,5003,000 (with supplemental feeding). Supplemental feeds are rice bran, chopped cassava, corn kernel soaked in water, poultry feed, kitchen refuse and others. Harvesting the fish is done by draining the field

Palawija ikan system


The above systems are combined into sequential cropping patterns in a year such as:

· Mlnapadl

- penyelang

- minapadi

- palawja

(rice + fish)

(fish only)

(rice + fish)

(fish only)

· Rice - penyelang - rice - palawija
· Rice - rice - palawija
· (Rice + fish-duck) - (fish-duck) - (rice + fish - duck) - (fish-duck)

In the last pattern, the ducks are allowed to roam in the ricefield 25-30 days after transplanting the rice. Ducks have potential for controlling golden snail (Panacea sp) infestation on rice. The number is 25 ducks/ha. The ducks have a small refuge pond where they are kept when necessary.

Cropping patterns

The addition of ducks in the last pattern made it the most profitable pattern. The year-round supply of eggs provides monthly income to a farmer. In the absence of ducks, the minapadl-penyelang-minapadlpalawila pattern is the most profitable.

Fish stocking and production data.







15 - 25 9

2,500 - 3,000

100 - 200



15 - 25 9

2,500 - 3,000

70 - 100

30 - 40


5 - 8 cm


200 - 300


30- 50

1,000 - 3,000

300 - 800

60 - 70

50 - 1 00



Rice-fish systems in China

Rice-fish farming, an age-old farmer practice in China, can be traced back more than 1,700 years, although recently it has been largely ignored. Integrated rice-fish farming in China is generally characterized by four basic components: (1) extensive use of land; (2) low input; (3) low yield; and, (4) household consumption of rice-fish production.

After the founding of the People's Republic of China, the government organized farmers and encouraged them to develop integrated rice-fish farming systems. As a result, hectarage under rice-fish farming reached 700,000 ha in 1959, but sharply declined in the 1960s and 1970s due to the wide use of pesticides, reformation of the cropping systems and me unfavorable national economic policy during the Cultural evolution" period (1966-1976). During this period, acreage of rice-fish farming dropped from 40,000 ha to 320 ha in Guangdong Province and a similar drop from 230,000 ha to 5300 ha was documented in Hunan Province. However, during the recent "refomnation" and Opening" period, the government is again encouraging the adoption of rice-fish farming.

With farmer initiative and assistance from the government, the adoption of rice-fish farming is rapidly expanding. It has traveled from Guandong Province in the South to Hei-Long-Jiang Province in the north and has reached historical proportions with more than 1 million ha in 1986. Sichuan, Hunan, Guizhou and Fujian are the four top provinces in China.

Rice-fish systems are principally found in the hilly areas of the Yangtze river basin and other parts of Southern China, although some rice-fish can be seen in northern provinces. The traditional rice-fish systems presented here are found in both irrigated and rainfed areas. The improved designs are principally found in irrigated conditions. Most rice-fish farmers in China are cooperatives farmers" with small landholdings of 1,500 sq m or less. Nommal fish pond size is usually 1,000 sq m.

Major component technologies of rice-fish systems in China are presented here.

2 Chinese "mu" (1 mu = 0.67 ha) 1 chinese "mu"

Rice-fish farming system (Hubei China)

1. Appropriate Construction of Paddy Field

· Traditional Paddy-Field Without Trench

The traditional paddy field layout has no trench or pond in the field and the water storage capacity is limited. Fish growth is more directly effected by rice crop management and the result is a low and unstable yielding.

· Trench-Pond Integrated Rice-Fish Designs

“Trench-Pit" Design

This is an improved design with a small, shallow pit (1-2 sq m) in the center of the field. Crossing trenches are dug to connect the pit to all side trenches. Increased water storage capacity offers a better refuge for the fish. This design raises rice yield by 10% and 1-2 times as many fish can be raised as compared with the traditional design.

"Trench-Pond" Design

This design is a further improvement with a larger, deeper pond at one end of the field. Crossing trenches are also dug to connect the pond to all sides. This design significantly increases the water-storage capacity and provides a better environment for the fish. It raises and stabilizes the yield of both rice and fish.

· "Ridged-Field" Rice-Azolla-Fish Model

This design was originally developing for swampy areas with objective of improving soil properties and increasing rice yield. Later, it was step-wise integrated with azolla and fish. Rice is planted on the ridge, azolla as a feed for fish as well as a bio-fertilizer and green manure and fish are stocked in the trenches.

Azolla is a small aquatic (usually 1-5 cm large) which can grow on saturated or moist soils. It is capable of doubling its weight in 3-5 days. Azolla fixes atmospheric Nitrogen and can fix 3-7 kg N/Ha daily. It contains 4% Nitrogen on a dry-weight basis and is an excellent source of nitrogen fertilizer.


RICE (total for two crops/year)


AZOLLA(fresh weight)

862 kg/mu

50.21 kg/mu

2,010 kg/mu

12 916 kg/Ha

753 kg/Ha


2. Basal Fertilizer Application

Physical injury to fish caused by inorganic fertilizers used in rice production can be a constraint to rice-fish systems. Necessary measures should be taken to minimize fish injuries. One such measure is to increase the amount of the basal fertilizer application during the land preparation stage to approximately 80% of the total nitrogen and 100% of the total phosphorous requirement

Basal fertilizer application

3. Transplanting

Reduced rice plant population within the ridged field paddy design caused by the construction of trenches and refuge ponds is one farmer constraint to the practice of rice-fish systems. Farmers can lose as much as 10% of their paddy when constructing trenches and refuge ponds for ricefish systems. In order' to minimize reduced plant population (and potentially reducing crop yield), plant spacing can be intensified by reducing the recommended distances between hills while maintaining the row spacing (20-25 cm). Normal hill spacing of 15-20 cm between plants can be cut in half to 7.5-10 cm, thus doubling the plant population in the side-rows of the trench.

Basal Fertilizer Application

4. Fish Stocking Considerations In Rice-Fish Systems

· Grass carp, common carp, Nile tilapia and crucian carp are four predominant species for polyculture rice-fish farming in China. One such system involves four species: grass carp (Cyen opharyngodon idellus), Tilapia sp., common carp (Cyprinus carpio) and crucian carp (carassius aurotus), with the first two species making up the majority. The recommended mix is a 25-45% composition of both the grass carp and tilapia (a total combined composition of 70%) with a 15% mix of both common and crucian carp (remaining 30%) at stocking rate of 2-3 sq m. This mix of species can give an optimal yield of both rice and fish.

Fish stocking

· When stocking fingerlings in the pond or paddy, a large difference in water temperature between the container used to transport the fish and the paddy can lead to fish loss and a poor survival rate. Therefore, it's recommendable to mix water from the paddy with the water in the container to slowly regulate the temperature differences and allow the fish to adjust to the water temperature of the field.

Large difference in water temperature between the container used to transport the fish and the paddy can lead to fish loss and a poor survival rate.

5. Top dressing Fertilizer Application

Top-dressing fertilizer is applied at the panicle differentiation stage (about 28-30 days to heading). A shallow layer of standing water in the paddy is necessary for fertilizer application, but can increase the possibilities of injuring the fish. However, two alternatives exist which can help to minimize these limitations.

Fishes in trench: Fertilizeren

· Slowly drain the water from the paddy allowing the fingerlings to return to the refuge trench/pond. As the water in the ridges almost dries, the top-dressing (broadcast) can be applied, thus controlling injury to the fish as well as achieving fertilizer efficiency. Two to four days after the fertilizer is applied, the field is again flooded. To irrigate and to open the water layer in field before top-dressing.

Fertilizer application can be done by deep placement by hand or by using machinery. The fertilizer should be applied at a depth of 810 cm. Fertilizer efficiency and reduced risk

Fertilizer application to fish health are also attained. (Note: The paddy should also be drained for using the deep-placement method.)

6. Pest Management

· Weeds

Stocking fry in newly transplanted rice field

Stocking fingerlings in established rice paddy

Many weed varieties found in the rice paddy are good feeds for grass carp. Stocking fry at 2-3 pieces/sq m (2-3 cm long) fingerlings at 2-3 pieces/10 sq m or (-10 cm long) one month after transplanting can help to control weeds, thus, reducing the need for other weed-control techniques. As the fingerlings grow, daily supplemental feeding with green grasses is necessary to avoid damage to the young rice plants by the fish. Grass is usually fed to the fish in the pond to avoid damage to the rice plants; while rice bran and other supplemental feeds can be directly fed to the fish in the paddy area.

Fish in the paddy area.

· Insects and Diseases

Fish eat insects, such as stem borer and leaffolder which move through the water among the rice plants and hoppers which catch them as the float on the water from the riceplant. Fish reduces need for pesticide. Fish also eat the pathogens (such as sheath blight disease) floating in water and on the bottom as well as disease infected leaves, therefore, not only reducing the pathogens but also improving plant's health. Thus, the use of fungicides can also be reduced. If pesticides must be applied, certain precautions should be taken. In traditional fields, the field should be flooded with more water.

Insects and diseases

Pesticide Application

Similar to fertilizer application, damage to fish health can be incurred with the application of pesticides to the rice crop. However, using simple techniques such as slow field drainage, allowing the fish to return to the trench/pond, cautious application of the pesticide, an allowance for a brief waiting period and re-irrigation of the field after application can help to ensure minimal losses due to pesticide poisoning.

In fields with trench/pond designs, the water should be drained into the trench or pond, thus driving the fish into the refuge area before the application of pesticides.

In traditional paddy field design, fish can be driven to one half of the field and pesticide application can be done in the other half of the field. The same procedure can be repeated to the other half of the field on the following day.

Prepared by: GUO YIXIAN


Rice-fish system in Guimba, Hueva Ecija, Philippines

Guimba, Nueva Ecija, in the Philippines has rainfed and irrigated rice-based agriculture. In rainfed areas, rice is grown during the wet season and remains fallow during the rest of the year. In irrigated condition, rice grown during the wet season is followed by another crop of rice during the dry season. Ricefish culture is practiced by some farmers. In areas with extremely light soils, farmers plant vegetables (e.g., squash, cucumber, mungbean, stringbeans, onions, bitter gourd, etc.) and water melon after wet season rice.

The rice-fish system practiced by farmers in Triala Village, Guimba is concurrent rice-fish with pond refuge. This system is for growout of Nile tilapia. The operation is done as follows:


Rice-fish field

1. Site Selection

· Abundant and dependable water supply. Irrigation water, ground water, spring and other water sources are used when they are not contaminated by pesticides.

· Clay soil is best. Clay holds water, prevents seepage and leaching of fertilizers.

· Choose site with good drainage and is free from flooding.

2. Design and Size of Field

· Independent filling and draining of each rice-fish compartment is considered.

· Ease of fish movement into the rice fields during grazing and draining is also considered. Fishes should be able to get quickly into the canals or refuge when water level is very low.

· Size of rice-fish plot considers the natural partitions of the field. Small plots are easy to manage and fish survival is usually high.

Examples of fish REFUGE LA layout for small and large plots

· Dikes are made strong and big enough to contain 30 cm. of water

3. Fish Refuge

Pond refuge is preferred over trench refuge. It holds more water and is less risky. Refuge size is usually 10% of the ricefield area. Bigger refuge or a pond adjacent to the ricefield may also be connected to it through a canal.

To construct the refuge, the pond is excavated at one end, or two ends if the field is large, inside the ricefield or adjacent/alongside but connected to the field so that the fish can have access to the area planted to rice.

4. Inlet and Outlet Gates and Screens

These are made of bamboo and other low-cost materials. Screens prevent the escape of stocked fish or entry of unwanted fish into the field.


1. Rice varieties—High-yielding varieties; maturity period of 120-130 days; resistant to insects and diseases.

2. Seedbed preparation and seeding rate—




100-150 kg /ha


broadcast urea at 25 kg/ha. 10-15 days after sowing.

3. Land preparation - After plowing once and harrowing thrice, the field is levelled evenly so that every part of it will be uniformly irrigated.

4. Rice transplanting methods -

Age of seedlings:

25-30 days

Planting distance:

20-25 cm between rows

15-20 cm between hills

Straight-row planting (optional), if mechanical weeding is done.

5. Weed control—Fish stocked in ricefields control certain weeds. Weeds are also controlled through:

· thorough land preparation
· flooding the field at an effective water depth for one to two weeks immediately after transplanting.
· manual weeding

6. Water management—Water depth in the field when rice is newly transplanted is 3 - 5 cm. This is then gradually increased up to 20 cm. to provide better living space for both rice and fish as they grow bigger. One week before the rice harvest, water is slowly drained so that fishes have enough time to move into the refuge.

Water management A


Water management B

Water management C

7. Fertilizer application—The amount of fertilizer applied follows the recommended rate in the area. In Guimba, the rate applied during wet season is 200 kg/ha of ammonium phosphate and 50 kg/ha of urea for the first or basal application. The basal application is done immediately after the final leveling, (which is followed by transplanting). The rate for the second application or topdressing is 50 kg/ha. This is applied 30 days after transplanting. The amount for top dressing may be split into two equal applications Thus a third application is applied 75 days after transplanting.

During dry season, the same amount for basal application is followed. For topdressing, the rate is 100 kg/ha.

As an example, the amount of fertilizer for a 400 sq m of rice-fish during wet season is: 8 kg ammonium phosphate and 2 kg urea for basal application. For topdressing, 2 kg urea is needed.

8. Insect control—The use of insecticide is not recommended. The farmers, however, apply insecticides known to be less toxic to fish.


Colocasia sp., an aquatic plant, is an excellent food material. It can be grown as an added commodity in a rice-fish farm. Practically, all parts of the plant can be eaten (tubers, stalks and leaves). It can also be utilized as food for the fish and for animals, especially pigs. The cultural requirement is simple and it requires no expensive inputs.

Colocasia planting


1. Obtain young tubers as plant materials.
2. Cut old leaves but retain the young leaves and shoot.
3. Cut the tuber into half

Cut the tuber into half

4. Plant the tuber at 50-70 cm intervals along the side of the dike, about 5-10 cm below the water surface.

5. Start harvesting after 4-5 months.


The species cultured are Nile tilapia (Orechromis niloticus) and common carp (Cyprlnus carpio). Large fingerlings, 15-25 9, are recommended as they reach harvestable size within one rice crop. It only small fingerlings (5-109) are available, fish culture is done in two stages:

Stage I: Raising 5-10 9. fingerlings during one rice cropping (harvest size: mostly 50 9.)
Stage II Extending fish culture period after rice harvest for up to 2 months (harvest size: 50 9.)

Fish Stocking density

· Stocking can be done before or during land preparation in the pond refuge; or 7-10 days after transplanting (DAT), if released direct to the field. If stocked in the pond refuge animal manure should be applied into the refuge 4-5 days before fish stocking. About 15 kg may be applied in a 100 sq m pond refuge.

The stocking rate for Stage I, using either monoculture of Nile tilapia or polyculture of Nile tilapia and common carp is 5,000- 7,500 fish/ha. For polyculture, the stocking ratio of Nile tilapia to common carp is 1:1 or 2:2, depending on which species is more important to farmers.

· Ten days after transplanting, fish stocked in the pond refuge may be released to the field by making openings in the dividing dike. Fish will graze on the natural food available in the ricefield.

Supplemental feeding

· Recommended at the middle culture period or rice (45-50 DAT). During this period, production of natural food in the field water declines due to shading of rice leaves.

· Feeds: rice bran, kitchen refuse, ipil-ipil meal, etc. Animal manure may also be applied in the pond refuge.

· Feeding rate: 3-5% of fish biomass


· Harvest fish by draining the water very slowly one week before rice harvest to avoid trapping the fish in the middle of the field.

· Select large fish for consumption or disposal and confine the small fish (50 g.) for stage 11 culture.

· After removing the harvested rice from the field, it is immediately reflooded to about 30 cm deep and the small fishes in the refuge are released to allow them to grow for another 60 days before the dry season crop.

Timetable for rice-fish culture




Prepare and fertilize seedbed.


Soak seeds (IR-36, 42, 52, 54, 64 and 74 as examples).


Broadcast germinated seeds in seedbed.


Prepare ricefield:

Start of fish culture (STAGE I):
Stock fish (Nile tilapia, 5-10 g in size) at 5,000- 7,500/ha. Insure water supply infields.


Pull seedlings. Apply basal fertilizer. Use the kinds and rates of fertilizer recommended for the locality based on soil analysis.


Transplant seedlings (wet bed method).


Second application of fertilizer (top dressing). May split the amount into two applications hence the third application.


Third application of fertilizer (top dressing)


Drain water and harvest large/marketable fish.


Harvest rice.


Start of fish culture (STAGE Il): Prolong fish culture period after rice harvest for small-sized fish (30-40 9) stocked at 3,000-5,000/ha.


Harvest second batch of fish.

Time for rice-fish culture


1. Fish can contribute to increased rice yield by 1 10-15%, through:

· Controlling certain weeds and eating insects such as stemborer, brownplant hopper

· Fish wastes including uneaten feeds add fertility to the soil.

· Helps in increasing availability of nutrient for increased floodwater productivity and uptake by rice.

· Reduces loss of ammonia through volatilization by preventing floodwater pH rise over 8.5. During fertilizer application increased plankton production tends to raise the value of pH beyond 8.5; the value at which ionized ammonia converts into unionized form that is easily lost.

2. The increased size of dikes in the system offers opportunity to plant other crops such as faro (colocasia sp.), stringbeans, cowpea, wingbeans, eggplant and others.

3. The wide scale adoption of rice-fish is still constrained by continued application of pesticide in ricebased farming. The use of pesticide is not recommended in rice-fish farming. There are ways of controlling rice pests that do not need pesticide, such as:

· Quick submergence (for three hours) of rice plants in water. This makes the insects vulnerable to fish predation. Limitation: suitable while rice plants are shorter than the dike.

· Two persons can drag a stretched rope (50-100m) across the ricefields to knock off the insects into the floodwater, after which they can be eaten by the fish. Limitation: suitable before rice plants reach panicle initiation stage.

However, should a farmer insist on using pesticide, here are ways how to do it:

Considerations in applying pesticides:

(1) Choose and apply properly pesticides that have low toxicity to fish.
(2) Minimize the amount of pesticide getting mixed with water.
(3) Apply at suitable time.

Preventing fish poisoning:

- Drive the fish into the refuge by draining the field before spraying. Keep the fish in the sump until the toxicity in the sprayed field is gone.

- Increase water depth (+ 10 cm.) to dilute the concentration of pesticide in the water.

- Flush water through the ricefield. Open the inlet and outlet of the field and allow irrigation water to flow freely, during spraying. Begin spraying from the outlet end of the field. When one-half of the field is already sprayed, stop for a while and allow the pesticides to flow out of the field. Then, continue spraying towards the inlet end of the field until it is finished.

To do items (2) and (3), examples are: apply powder pesticides in the morning when dew drops are still on the leaves; and to apply liquid pesticides in the afternoon when leaves are dry.

There are a number of less toxic pesticides in the market (Examples are Parapest, Sumithlon, Dipterex). Proper application of a toxic insecticide like Furadan 3G or Curaterr 3G can be made safe to fish if applied through soil incorporation during the final harrowing. Furadan 3G is a systemic insecticide, the efficiency of which in controlling insect pests lasts about 50-55 days. Incidence of pests at this period can be controlled by spraying liquid pesticides. At this time, the rice plants have reached their full vegetative stage and the thick leaves will intercept most of the liquid sprays, thus drastically reducing the concentration of pesticide reaching into the water.

Annual budget for a 1-ha rice-fish farm with pond refuge.


Amount (US$)

I. Returns


Rice-Fish + Taro

Rice (2 crops)



Fish (2 crops)



Taro (2 crops)


Total Returns



II. Costs













Taro tubers









Fuel and oil






Others (screens, bundling materials, etc.)



Total costs



III. Net Returns



The case of rice-fish farmer mang isko,dasmarinas, cavite, the Philippines


Mang Isko is a 66 year-old farmer. Together with his wife, who is 60, they have eight children most of whom are grown up and living away from home. The only son is married and living with his wife and children near the farm of Mang Isko. This son helps Mang Isko in the day-to-day management of the farm. Two daughters are attending high school and still live at home. Two older daughters are living and working abroad in Japan. They send remittances home on a regular basis (P4,000/month) to support the education of their younger sisters.


Mang isko's farm transect (lowland farm) dasmarinas. Cavite Philippines

Mang Isko farms 2.3 ha of lowland with access to irrigation water from the National Irrigation Administration distribution system. Two rice crops are grown in 1.44 ha. Half a hectare is devoted to ricefish culture. In some years, gourd are planted on the rice-fish dikes after the second rice harvest. Other vegetables occupy 0.14 ha of the term where bittergourds are planted in the dry season and relayed with stringbeans in the wet season. The remaining 0.2 ha houses 1 pig in a 15 x 12 m shed and the rest of the area are grown to fruit and fodder trees and grasses.


The 0.5-ha rice-fish system is composed of eight individual fields with side trenches. Two rice-fish plots have adjacent pond refuges in addition to the trenches. One rice-fish plot has an adjacent pond which is managed as a breeding pond. Mang Isko practices rice-fish culture in both wet and dry seasons and harvests two crops of rice and fish in a single year. However, when he plants gourd on the rice-fish dikes after the second rice-fish crop, he does not have a dry season rice-fish activity. In such occasions, the fields drained and the fish are are for for in the pond refuges.

Maag isko's on-farm material flows Dasmarinas, Cavite Phillppines

Combining fish with rice has doubled Mang Isko's rice yields in some cropping seasons. He attributes the increase in yield to these factors:

· Rice plants uprooted when digging the trenches are used to patch up vacant spaces in the ricefield where transplanted rice have not grown.

· The beneficial effect of fish on rice growth is manifested in the increased tillering of rice plants and the uprooting of young weeds when the fish (carp) stir up the bottom of the field in their search for food.

· The introduction of fish has meant that Mang Isko spends more time in his farm. Thus, he can spot and remedy problems immediately. In his own words, he has become " a better farm manager "

· Fish eat rice pests, thus rice yields are less threatened by pest damage.


1. Land Preparatlon, C onstruction and Malotenance

· Dike construction is labor demanding. According to Mang Isko, it has been the biggest obstacle to the rice-fish adoption. Large dikes are required to avoid dike collapse and minimize water seepage and overflow. The dikes must be cleaned and weeded regularly to prevent damage by rodents.

· The trenches are dug one month after rice transplanting. The dug-out mud is placed on the dikes for maintenance and is the source of fertile soil for the subsequent cultivation of gourd. Also, at this stage, the dug-out soils are more compact as they have been soaked with water and this makes dike construction easier.



White squash in dry season rice-fish field

· Mang Isko uses one of the eight rice-fish fields with the highest elevation, as a test-field for monitoring water quality that comes in from the irrigation canal. This is to ensure that contaminated water due to pesticide applications of neighboring farms do not get into his rice-fish fields. The irrigation water is let through this field first and any adverse effect on the fish is observed. The field is only lightly stocked (50 fish per 800 m).

2. Rice Transplanting and Management

· Rice is transplanted 10-12 days after sowing in seedbed.

· Around one month after transplanting, three rows of rice, occupying about 60 cm, are removed for the purpose of trench construction. The uprooted rice plants are used to replace transplanted rice that have not grown.

· According to Mang Isko, IR 64/74/42 varieties are not suitable for rice-fish as they easily lodge.

· He will try to use an early-maturing rice variety for the dry season to avoid any critical water shortage. At present, he uses a 90-day maturing variety for both seasons.

3. Fish Stocking and Management

· Mang Isko keeps a separate breeding pond. The advantage of having a breeding pond is that fingerling supply is ensured. Moreover, he could stock larger-sized fingerlings which can be harvested as tablesized fish immediately before rice harvest. However, without proper broodstock management, he had an inbred population after three years as reflected by stunted fish growth. After five years he did not keep any brondstock.

· Fingerlings are stocked in the pond refuges immediately after rice transplanting. After one week, the dikes connecting the pond refuge and the rice-fisy plots are broken to let the fish in the rice-fish plots. (Stocking density: 1 tilapia/m and 1 carp/5 m)

· The fingerlings/fish are graded into four classes when transferred from the breeding pond to refuge ponds and rice-fish fields. Class I = < 25 pieces/kg; Class II = 35 pieces/kg, Class III = 40 pieces/kg; and Class IV = > 50 pieces/kg. This is done in order to avoid cannibalism and competition that would otherwise lead to large fish stunting the growth of small ones.

· One week after trench is constructed, the trench is filled with water and fish are stocked.

4. Fertilizing and Feeding

· Rice straws from the previous crop are burnt and the ashes are returned to the fields for liming.

· Pig manure is thrown directly into the ponds or left by the water inlet to let the water carry/wash K into the rice-fish fields.

· Fish feed on fallen rice flowers. Mang Isko believes that this has a purifying effect which counteracts the perceived off-flavor taste of tilapia due to the presence of pig manure in the system.

· Rice bran is given one week after stocking in refuge ponds and trenches until two weeks before fish harvest. This is done twice a week or when required as may be signalled by the inactive behavior of fish or its stunted growth.

· Three weeks after transplanting, 100 kg of urea and 50 kg of complete fertilizer are applied to the ricefields.

5. Pest and Disease Management

· Carps eat hatched golden snail eggs dropping into the water; tilapias feed on insects.

· Mang Isko submerges the rice crop for three hours when insects become a problem. The fish then have access to feed directly on insects on the plants as well as insects trapped on the water surface. This practice is only carried out when the rice is 1-2 months old.

· Mang Isko reports that a neighbour of his uses Gliricidia (kskawate) as an insect repellent. In his first year of rice-fish, he placed Gliricidia branches of approximately 1 m length at 2 m intervals around the edge of the field at the booting stage of the rice, i.e., seven weeks after transplanting. He has now planted Gliricidia trees around the field as a means of biological pest control.

· When constructing the dikes, a layer of plastic is placed inside each dike. Rats find it slippery and difficult to penetrate the dikes with plastic lining.

6. Harvesting

· The fish are harvested by draining the field three days before rice harvest. The water level in the refuge is lowered to a couple of inches and the fish are caught by hand.

· Table-sized fish are sold. Fingerlings are kept for the next crop. Fish sizes that are in-between are returned to the pond refuge for further growout. They are sold or consumed at home as demanded. This is a source of continuous income from fish.

Mang isko's calendar of farm activities Dasmarinas, Cavite, Philippines (A)

Mang isko's calendar of farm activities Dasmarinas, Cavite, Philippines (B)


Initial cash costs for vegetable growing were incurred in the first months of operation.

The cash requirements for rice monoculture and rice-fish culture were more spread over the months.

Unscheduled fish harvests in between two total harvests are a source of continuous income or cash inflows that help relieve cash constraints in certain months.

Mang isko's monthly cash flows of all farm operations.

· There were five months in the year where the cash obtained from the sales of rice, fish and vegetables were greater than the cash spent on farm operations.

· The months in between rice and fish harvests were the months that cash deficit was greatest.

· Although there were sales received from vegetables before the rice and fish harvests, there were not enough to cover the large expenditures on inputs particularly inorganic fertilizers.


As a whole, farming for Mang Isko was profitable. At the end of the year, he earned P45,233.80. He used this money primarily to sustain his wife and two children. A part of this was spent on upgrading his living condition, that is. he was able to improve his house and was able to purchase a refrigerator and a television.