Trends in Rice

Background

Rice is grown in irrigated, rainfed lowland, flood-prone, and upland ecosystems. The irrigated rice ecosystem, with approximately 81 million ha worldwide, accounts only for 53% of the world's harvested area of rice but produces 76% of the global rice production. Of the remaining area 27% is rainfed lowland, 8% is flood-prone, and 12% is upland. In the 1990s the world rice area has remained more or less constant at about 148 million ha. Almost 90% of this area is in Asia. India is the largest grower of rice with 42.3 million ha followed by China with 33.0 million ha (Table 1). The irrigated rice environment is supposed to be the main contributor to the much needed future increase in production, but yields under continuous and intensive cropping conditions are either stagnating or declining.

As a result of development aid donors and governments focus on sustainable rural development, food security, and poverty alleviation, rice-fish farming systems have received a great deal of attention in the recent past. Several reviews on historical, socio-economic, and ecological aspects of rice-fish farming have been published in the past decade with either a global or a national focus (Li, 1988; Fernando, 1993a; Halwart, 1994a; MacKay, 1995; Choudhury, 1995; Little et al., 1996). Country overviews have been provided for Bangladesh, China, India, Indonesia, Korea, Malaysia, Philippines, Thailand, Viet Nam, and Madagascar (for Asian countries: dela Cruz et al., 1992; for Madagascar: Symoens and Micha, 1995). An extensive bibliography on diverse aspects of fish culture in rice fields has recently been compiled by Fernando (1993b).

Rice-fish farming systems can be broadly classified as capture or culture systems depending on the origin of the fish stock. In the capture system wild fish enter the rice fields from adjacent water bodies and reproduce in the flooded fields. In contrast, rice fields are deliberately stocked with fish in the culture system either simultaneously or alternately with the rice crop. The rice fields may be used for the production of fingerlings or table fish depending on the size of fish seed available for stocking, the duration of the fish culture period, and the market needs for fingerlings or table fish.

Technical details of the few physical modifications (bunds, trenches, water inlets and outlets) that are required to make the rice field suitable for fish farming have been described elsewhere (e.g. Capistrano-Doren and Luna, 1992). It is however interesting to note the differences in refuge size and shape. It can be a pond within or adjacent to the rice field, or a trench which may be central or lateral, or a combination (Figure 1 a - d). Different extremes for the size of this refuge area can be observed. For religious reasons farmers just dig a small sump in the rice field terraces in the Ifugao province in the Philippines, whereas in Viet Nam sometimes up to half the ricefield area is dug out because profits from fish sales exceed those from the rice crop.

Rice varieties are selected by the farmer for their suitability to agroclimatic conditions and preferred consumer taste. Past increases in rice yields have mainly come from the gradual reallocation of land from traditional to the high-yielding modern varieties. These are short, stiff-strawed, fertilizer-responsive, photoperiod-insensitive, and have short to medium growth duration (100-130 days). The use of long-stemmed long-maturing traditional varieties allows a higher water table and an extended period for fish farming. However, as the case of the P.R. China (with 1.2 million ha under rice-fish farming in a rice area almost exclusively planted to modern varieties) shows, the use of modern rice varieties is not a constraint for rice-fish farming (Figure 2).

Many fish species can be harvested from rice fields but only few are commercially important. The most common and widespread fish species used in rice-fish farming are the omnivorous common carp Cyprinus carpio and the planktivorous Nile tilapia Oreochromis niloticus. They feed low in the food chain and are therefore preferred species in the culture systems. Other popular species are Puntius gonionotus and Trichogaster spp. Many air-breathing species such as the snakehead Channa striata or catfishes Clarias spp. are well adapted to the swamp-like conditions of rice fields, with fluctuating water levels, and are highly appreciated wild fish in the capture system. They are carnivorous and will feed on other introduced fish but, for example in Thailand, can be sold for twice the price of cultured fish at local markets.

Generally, Integrated Pest Management (IPM) practices are recommended for rice-fish farming. The use of pest and disease resistant rice varieties is encouraged to minimize pesticide application. In rice monoculture, the chance of pests reaching a population level which economically justifies control action is usually low. The potential income from fish shifts the economic threshold to a level which is even less likely to be reached by pests. Also, from an IPM point of view, fish culture and rice farming are complementary activities because it has been shown that fish further reduce pest populations. Evidence from the FAO IPM Intercountry Programme in Indonesia shows that, through IPM, the number of pesticide applications in rice can be reduced from 4.5 to 0.5. This not only reduces costs but also eliminates an important constraint to the adoption of fish farming.

there and put into rice fields for hatching, or broodstock was released into rice fields for natural spawning. Significant progress was made in the 1980s when many other fish species (grass carp, crucian carp, silver carp, bighead carp, etc.) in combination with new production techniques (e.g. `rice on ridge - fish in furrow' cultivation, raising fish with azolla) were tested. Sichuan with 333,300 ha of rice-fish farming, Hunan (227,000 ha), and Guizhou (87,300 ha) were the three top provinces in terms of area (Figure 3). An average annual fish production from concurrent rice-fish farming of 180 kg/ha has been reported although fish yields exceeding 750 kg/ha can be achieved (production patterns and technologies, ecological interactions, and economic benefits are described and analyzed in MacKay, 1995). Production is approximately twice as high in rotational rice-fish farming systems. P.R. China officially promotes fish farming in rice fields in its National Aquaculture Development Plan (FAO and NACA, 1997), but the rise in freshwater fish prices is probably an important incentive for a more rapid adoption of this integrated farming (the average price for common carp in P.R. China increased by 47% from 1992 to 1995, (FAO, 1997)). According to the most recent figures provided by the Bureau of Fisheries, Ministry of Agriculture, P.R. China, there has been a continuous increase in fish production from rice fields with a peak of 377,000 t on an area of 1.2 million ha reported in 1996 (Figure 4).

The second most important country in terms of rice-fish area is Egypt. There has been a considerable expansion in rice-fish area in the 1980s with a peak of 224,917 ha in 1989, at a time when the price of rice was not favourable (in comparison to other summer crops) and new reclaimed salt-affected land was taken under cultivation with continuous flooding and fish production. This situation changed after 1989. Rice prices increased, the adoption of high yielding rice varieties led to a higher productivity, and reclaimed lands were converted to rice monoculture. As a consequence, the rice-fish area has declined to 172,800 ha in 1995, which is still equivalent to 37% of the rice area (Figure 5). Fish production from rice fields accounted for 32% of the total aquaculture production of the country in 1995 (Shehadeh and Feidi, 1996).

In Indonesia the fast development of grow-out operations, such as running water systems and cage culture in reservoirs, has fueled an increased demand for fingerlings. With limited nursery capacities, the potential of using rice fields quickly became evident and rice-fish farming for fingerling production became

popular among rice farmers. In the period 1977 to 1984 fish production from rice fields increased from 17,701 to 58,880 t. The area under rice-fish peaked in 1982 with 137,384 ha under production. Although the rice-fish area decreased to 94,309 ha in 1985, total fish production from rice fields increased with average annual fish yields reaching 670 kg/ha, more than double the production of 306 kg/ha in 1982. Rice-fish farming is practised in 17 of the 27 provinces in Indonesia, in particular in all provinces in Java and the northern provinces of Sumatra except Riau and Jambi. Most of the 94,309 ha recorded in 1985 are located on Java (64,855 ha), followed by Sumatra (14,387 ha), Bali-Nusa Tenggara Islands (9,361 ha) and Sulawesi (5,706 ha). No records or few data exist for Kalimantan, Maluku, Irian Jaya or the outer islands but rice-fish farming is probably more widespread than indicated by current data (Koesoemadinata & Costa-Pierce, 1992). After 1986, rice production practices in Indonesia changed dramatically when IPM was declared the official national pest control strategy. Pesticide subsidies were removed, and 57 out of 66 insecticide formulations used on rice were banned. How IPM served as an entry point for rice fish farming is perfectly documented in the case of an Indonesian farmer (Van de Fliert and Wijanto, 1996). The latest figure (1995) on rice-fish area (138,277 ha), provided by the Indonesian Directorate General of Fisheries (Siregar et al., 1998) indicates that rice-fish farming is on the rise again.

It is difficult to get reliable figures on rice-fish farming in Thailand because the volume of the traditional capture of fish in `trap ponds' is generally not recorded. However, with 86% of its rice area being rainfed, ricefield capture fisheries plays a dominant role. In approximately one third of the country's 9.3 million ha rice lands, fish are captured at average yields of 25 kg/ha. In addition to this, there is a significant catch from small ponds constructed for water holding purposes along streams and canals and ditches between roads and rice fields. Ricefield culture fisheries was reported from 2,820 ha in 1983 (mainly Central, North, and Northeast Provinces). The steep production increase in the 1980s can probably be attributed to two major factors: a general decrease in wild fish availability, further aggravated by the occurrence of the ulcerative disease syndrome in wild fish stocks from 1982 onwards, and an improved supply and distribution of cultured fish seed. The combined impact of these factors was so significant that the area of ricefield culture fisheries expanded to 23,900 ha in 1988 and further increased to 25,500 ha in 1992 (FAO and NACA, 1997).

economic aspects in the SADC region since 1986. Under FAO's new Special Programme for Food Security (SPFS), fish farming in irrigation schemes in LIFDC countries currently receives a great deal of attention.

Invaluable research and coordination work has been performed by the two CGIAR (Consultative Group on International Agricultural Research) centres with a mandate for rice and fish farming, the International Rice Research Institute (IRRI) and the ICLARM. Supported by ADB and IDRC in the late 1980s/early 1990s and operated through the Asian Rice Farming Systems Network (ARFSN), the two centers have collaborated with many national institutions to improve existing rice-fish farming systems and to facilitate information exchange among participating countries. The technical feasibility and the improvement of rice-fish farming systems is still an important issue today in many locations but is usually considered in a more holistic way within the framework of socio-cultural and economic constraints. For example, an USAID funded project between ICLARM, the Bangladesh Fisheries Research Institute (BFRI) and various NGOs has studied concurrent rice-fish farming in medium highlands and lowlands and rotational culture in deeply flooded lowlands in order to develop sustainable low-external input practices that fit into the existing farming systems. In an on-going IFAD funded project, ICLARM also collaborates with the Bangladesh Rice Research Institute (BRRI) and BFRI to develop options for rice-fish culture in the flood-prone rice ecosystem; e.g. fish farming in net enclosures, and to carry out studies on community management.

In Lao PDR the FAO Project "Development of Fish Culture Extension" has promoted improved practices of rice-fish farming including the development of technical capacity at national and provincial levels (see also FAN, vol. 14, p. 29). FAO and UNDP continue to support rice fish systems in a follow-up project (LAO/97/007) in 5 provinces. Also in Lao PDR, where mostly the traditional ricefield capture fisheries can be found with various forms and degrees of community management, a DFID¹-funded on-farm research project on rice-fish farming is underway addressing technical, social, and economic constraints to rice-fish culture (Haylor, 1995). The role of women is emphasized. The project links researchers from the Institute of Aquaculture in Stirling, the Agricultural Extension and Rural Development Department of the University of Reading, and the Savannakhet Provincial Livestock and Fisheries Section, with

the AIT Aqua Outreach Programme serving as facilitator. Much research has focused on improvements of the traditional rotational rice-shrimp system in seasonal brackishwaters in the Mekong delta in Viet Nam. A Belgian Government funded project between the University of Can Tho and the Catholic University of Leuven aims to improve existing rice-fish farming systems in the Mekong delta. The University of Can Tho also collaborates with ICLARM in an IDRC-funded study on the socio-economics and productivity of integrated farms using the software RESTORE. Also in Europe and the US, the interest in the integration of fish and crayfish with rice farming is revived with researchers and farmers alike. The concurrent cultivation of rice and crayfish Procambarus clarkii has been investigated by research institutions in Louisiana, and commercially about 50,000 t are produced in 40-50,000 ha of shallow ponds, many planted with rice. The same species is also produced on a limited scale in rice fields in Spain with annual yields of around 5,000 t. There is apparently interest in culturing tilapia in Spanish rice fields but this has not started (Fernando, pers. comm.). In the Po delta in Italy, rice-fish farming was discontinued during the Second World War. Today, the University of Bologna with support from the Regione Emilia-Romagna has started to investigate fish management in rice fields under modern cultivation, as well as ecological and economic aspects of the integration (Lucchini, 1996).

In Latin America and the Caribbean, rice-fish farming has been tried with an emphasis on the technical feasibility in Argentina, Brazil, Panama, Peru and Haiti (Guillen, 1990). Often, local species have been used such as the silverside (Odontesthes bonariensis) in Argentina, or curimatá (Prochilodus argentes, P. cearanesis) in Brazil. Satisfactory results have been reported, but further extension is said to be constrained by a lack of trained technical staff, government interest, and international cooperation and promotion.

Integrated Pest Management (IPM)

It is increasingly recognized that Integrated Pest Management and fish farming in rice fields are

^1/DFID. Department for International Development, formerly ODA.

complementary activities. Several studies on this subject have been supported in the early 1990s by GTZ special projects through the CGIAR centres in collaboration with the Freshwater Aquaculture Center (FAC) in the Philippines, ranging from the biological control effect of fish on rice pests and their natural enemies to the socio-economic dimensions of rice-fish farming and IPM (Halwart, 1994b; Horstkotte, in press). In Bangladesh, two CARE projects (NOPEST and INTERFISH) focus on rice-fish farming as it relates to IPM. They are DFID and EU (European Union) funded and mainly oriented towards training and extension with some limited research. Training subjects in the NOPEST `training of trainers' programme include, among others, aquatic ecology, fish species selection, water management, fish feeding, fish physiology, fish seed production, and fish transportation. The training of trainers is done in collaboration with government IPM programmes funded by UNDP, and the FAO Intercountry Programme on IPM in Rice in South and Southeast Asia. Also in Viet Nam, many farmers have started fish farming in their rice fields after training in the national IPM Programme. A FAO Technical Cooperation Project, on the management of aquatic pest snails, promotes the use of carps for the biological control of snails, both in rice fields and communal waters (see also FAN, vol. 14, p. 30).

Studies relating to the feeding ecology of fish in rice fields receive increasing attention and have been completed in the Philippines, Thailand, Malaysia, and most recently in Bangladesh. Korean researchers have focused on the impact of indigenous fish species on malaria vectors in rice fields. A DANIDA and GTZ supported research area that has received much attention by ICLARM researchers is the modeling of biomass and nutrient flows and the development of sustainability indicators for rice-based fish farming.

Needs and Prospects for Rice-Fish Research and Development

Rice-fish farming will be more adopted the more it is compatible with rice management. The integration seems to have good prospects for the future because the reduction in pesticide applications and the use of less toxic compounds in rice production results in an increased ricefield biodiversity which is not only important for the balance of pests and their natural

enemies but also in a nutritional context for farming communities relying heavily on crabs, frogs, or snails from their rice fields. However, implications of the trend of increased use of herbicides in many countries will require further attention in the future.

Since rice can be grown both under submerged or saturated conditions, water is a critical factor in rice production. Much research and development efforts in rice-fish farming have concentrated on irrigated systems because the water level can be easily manipulated, but when farmers have to pump water, the costs often become prohibitive. However, in rainfed lowland rice, farmers tend to hold as much water in the fields as possible (by increasing the height of the ricefield bunds) to `insure' against insufficient rainfall. One country with predominantly rainfed rice (86%), Thailand, experienced a rapid expansion of rice-fish farming as fish seed availability improved. Similar developments may be expected for rainfed areas in countries as Lao PDR (61%) or Cambodia (48%), where declining wild fish stocks make aquaculture increasingly important.

Most rice-fish research and developments efforts are focused on culture of common carp and Nile tilapia. Promising indigenous species deserve more attention. A new interesting research aspect has been a study on the fecundity of the feral catfish Clarias macrocephalus in order to enhance the survival of wild populations in rice fields in Malaysia (Ali, 1993). Fish seed supply and distribution are crucial for the adoption of rice-fish farming. The experience from Madagascar suggests that the private sector may be in a better position to meet this demand, and development agencies increasingly recognize the different roles the public and the private sector may have in national aquaculture development plans. It is imperative that the rate of adoption in Madagascar is evaluated and `lessons learned' documented especially since external assistance has ended.

Rice-fish farming is particularly expanding in P.R. China where it is not only a traditional practice but is also actively promoted through the National Aquaculture Development Plan. It will be important in the future that Governments actively support the integration of rice and fish farming, and of agriculture and aquaculture, as part of their efforts to enhance food security and ensure sustainable rural development.

Acknowledgements

Thanks to the FAN editor, Z. Shehadeh, and FIRI colleagues M. Martinez-Espinosa and D. Bartley for their helpful comments and suggestions. Specific project or country information was provided by A. Ali (University of Science Malaysia), A.T. Badawi (Agricultural Research Center, Egypt), G. Chapman (CARE Bangladesh), C.H. Fernando (University of Waterloo, Canada), K. Gallagher (Global-IPM Facility), N. Innes-Taylor (AIT Aqua Outreach Lao PDR), M. Prein (ICLARM Philippines), A.M. Qureshi/S.P. Chen (FAOR P.R. China), A. Rothuis (University of Can Tho, Viet Nam), D.V. Tran (FAO-AGPC), J. Moehl and H. van der Mheen (ALCOM) and is gratefully acknowledged.

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	D = Dike R = Refuge (pond or sump) T = Trench