soon spread to Bangladesh, India, Thailand and most other Southeast Asian countries. While low levels of aquaculture were the general practice in the beginning, the trend has been toward intensifying pond culture and has been driven by an increasing demand for fish and decreasing amount of land suitable for expansion. Intensification entailed any combination or all of the following:
• Developing artificial spawning techniques to produce fry of desired species on a commercial scale
• Developing superior brood stock by selective breeding to produce superior genetic quality fry
• Liming and fertilizing the pond to induce the growth of natural food organisms
• Formulating and using balanced artificial feed to promote good growth
• Using pumps to ensure and stabilize the water supply
• Using artificial aeration to ensure oxygen is supplied in all layers of the water to increase carrying capacity
• Using pesticides to control predatory or harmful organisms
• Using probiotics to maintain the quality of pond environment
• Using genetically improved broodstock
• Ensuring freshness of the produce and a good market price with good postharvest care
Aquaculture in Asia has become characterized by its wide diversity in species and culture systems. It includes freshwater, brackish water and marine ecosystems. The species used for aquaculture production includes many finfish, shrimp, crab, oyster, mussels, abalone, sea cucumber and even seaweed. Aquaculture has been practiced in various systems: earthen ponds, tidal flats and paddy fields with peripheral dikes, concrete tanks, raceways, pens, cages and racks. Monoculture, polyculture and integrated aqua-agriculture have been developed to suit the region's diversified aquatic environment. However, pond culture remains the main source of aquaculture production in most countries.
Pen culture appears to be extensive in lakes and lagoons in the Philippines, where it is used mainly for milkfish and tilapia. The pens are enclosures made of synthetic or non-corrosive metallic mesh resistant to salt and sun and to crab cuts. The pen area may be enclosed by mesh on one to all four sides, depending on the topography. The bottoms and the tops of the enclosures are open, with no netting. Aquaculture of tilapia, catfish, sea bass, some species of carp and marine eel in fish cages has been popular in Japan, the Philippines, Thailand and Viet Nam. Like pens, fish cages are also made of synthetic, metallic or plant material, but unlike pens, the cage bottoms are closed. The tops of submerged cages are also closed. The cages are set in large ponds, lakes, rivers and bays. Racks made of synthetic fibers are hung in protected areas in the sea or in backwaters for oyster culture; the practice is common in the Philippines and some other Southeast and East Asian countries.
Aquaculture in seasonal monsoon water and floodlands, either in association with or alternating with paddy rice, has rapidly gained importance in Bangladesh, Cambodia, China and Viet Nam. The favored species are carp, tilapia |
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and prawn. In Bangladesh, about 50,000 ha of low-lying land that allowed only one crop of paddy rice during the dry season from January to May is now under prawn and carp aquaculture during the wet season. This multiple use has created excellent opportunities for rural farmers to enhance their income and nutrition. Some studies have suggested that this culture area should increase to at least 80,000 ha by 2015 (Karim, 2003)
2.2.7 Organic agriculture
Organic agriculture had two faces in ESAP. On one side, a small sector grew certified organic produce for the home market and for export to industrial countries. On the other side, a larger proportion, mostly subsistence farmers, farmed organically because they could not purchase or afford synthetic inputs. Organic farming could still be considered fringe farming and would only benefit a few producers for domestic or export markets. However, in recent years, driven by the rising popularity of organic products and the often higher financial return, many conventional farms are converting to organic farming.
Concerns about the environment and food safety in the use of agrochemicals in agriculture, especially pesticides, have led groups of farmers to form the organic movement and rely upon traditional methods of soil, nutrient and weed management. These methods have been designed to make the best use of natural cycles of nutrient flow, pest and disease control and competition to control weeds. To them, modern organic farmers add new technology not based on synthetic fertilizers or chemicals, and more recently, not on genetically modified organisms. The organic movement spread worldwide and now includes biological agriculture, ecological agriculture, nature farming, permaculture and biodynamics (IFOAM, 1996; FAO-WHO, 1999).
The area under commercial organic cultivation in ESAP is generally less than 1%. It lags behind Europe and Latin America, in part because development and uptake by farmers have been hampered by lack of supportive government policy in many countries (ESCAP, 2002). Bangladesh had the largest proportion of land, 1.9%, devoted to organic agriculture, with Sri Lanka 0.65%, China 0.6%, and Japan 0.56% also relatively large contributors (Willer and Yussefi, 2006). All other countries fell below 0.2% and most below 0.1%. This analysis omitted Australia because it was hard to compare with other data. Australia had, by far, the largest area of certified organic agriculture in the world, 13 million ha and 40% of the world area, but it was not a country with large organic fruit, vegetable or cereal production. The reported area included 11 million to 12 million ha of extensive zero-input grazing land of low productivity, with few products that enter the certified organic market.
2.2.7.1 Crop organic farming
A wide range of cropping techniques was employed to replace external chemical inputs with ecosystem functions (FAO, 2002). Organic management techniques were devised to support an integrated and holistic agroecosystem, which inhibited the growth of weeds, pests and diseases but enhanced favorable biological activity. The holistic and integrated approach fosters beneficial processes and interactions like those occurring in natural ecosystems, encourag- |