Rice and Shrimp Farming

April 12th, 2010 by Cyrus

Shrimp and rice farming has been part of Asia’s culture for a long time. They both are very popular in Vietnam. Vietnam is one of the world’s leading exporters of both rice and shrimp. Rice farming is a lot older than shrimp farming, but they both started in Asia.

Rice Farming in Vietnam

Rice farming started over 4000 years ago. Rice was first domesticated in the Yangtze Valley, which is in China. Rice is the staple food for over half of the world’s population.
Vietnam is the world’s second largest exporter of rice, behind Thailand. Most of the rice in Vietnam is farmed in the North and the South because the center of the country is very narrow and mountainous, while the North and the South have river deltas. In Vietnam, 75% of the cultivated land is planted in rice. In the North there are usually two rice crops planted per year; in the South there are three because it rains more in the South.

Rice can be used in lots of different ways. The average Vietnamese eats ¾ pound of rice per day in the form of plain rice, noodles, dumplings, rice paper, etc. The stalks of the rice are used to thatch roofs and to make sandals, hats and baskets; the husks are used to make charcoal. No parts of the rice plant are wasted.

Almost all rice is grown in the same way. It is grown from the seed in nurseries for 25-50 days. After that period, they are sold to farmers, who plant the crops in shallow ponds called paddies. The farmers wait until the rice plants’ leaves turn yellow, and then they drain the paddies. They harvest the plants with sickles and knives. The farmers wrap the rice in bundles and leave them in the paddies to dry for a few days. If the rice still isn’t dry, the farmers may lay the rice out on the highway to dry. After the rice is dry, they put it through a machine to separate rice kernels from the husks. These machines are usually owned by the community. After the machine has done its work, the rice has to be threshed. This means that the rice is put into a basket and tossed into the air. The aim is for the husks to be blown away in the breeze and the rice kernels to fall back into the basket. Threshing is usually done by women or girls, and it’s harder than it sounds. Then the rice is ready to eat or sell.

When farming rice, people aren’t the only animals used in farming. People use water buffalo not tractors, which get stuck in mud, to plow the fields. There are sometimes lots of scarecrows in some fields, just cloth hung on sticks, to keep the birds away. I also saw another interesting technique to keep birds away, someone had hung a net in a garden, and so if a bird flew into the garden, it would get stuck in the net. Sometimes people raise ducks in rice fields. The ducks fertilize the rice plants with their droppings. They also eat the weeds and insects from around the rice plants.
There are two different types of rice farming in Vietnam: dry rice farming and wet rice farming. Wet rice farming is more popular in Vietnam. Dry rice farming is practiced in places where it is not flat, like on mountain slopes or in steep valleys, it is fed by seasonal rains. Dry rice doesn’t require much work, but doesn’t yield much crop.

Shrimp Farming in Vietnam
Shrimp farming started in Asia in 1500 A.D., but has spread all over the world. Large scale shrimp farming didn’t start until 1900’s, when the demand was high and it made sense to farm it because it’s very expensive to farm shrimp. Most of the shrimp before the 1900’s was caught wild from the ocean. Now there are shrimp farms all over Vietnam.
Vietnam is the world’s third largest shrimp exporter, behind the United States and Thailand. Over 2 million people have jobs in Vietnam’s shrimp farming industry. In 2003 the US imported 588 million dollars worth of shrimp from Vietnam. 75% of farmed shrimp is farmed in Asia, and the other 25% is farmed in the Americas, especially in the US and Brazil.
There are two main species of shrimp farmed in Vietnam: the classic white shrimp and the giant tiger prawn. The shrimp are grown from eggs in nurseries for a period of 12 days then are bought by farmers. Farmers put the shrimp in either large tanks or ponds. The ponds are traditionally 1.5 or more meters deep (4-5 feet). After about 25 days, when the shrimps’gills branch, they are moved to another pond. They are in the grow-out ponds for about 3-6 months (depending on the species and place they are farmed). When they are ready to harvest, the shrimp are either caught in nets or traps.

Extensive shrimp farms are found along the coast where the real estate is cheap. Extensive shrimp ponds cover a lot of space, sometimes covering a square kilometer. In these ponds there aren’t many shrimp per square meter. The farmers don’t feed the shrimp; the shrimp feed on things they find naturally in the water. Extensive shrimp farms aren’t as expensive to run, but they aren’t as profitable. Intensive shrimp farmers usually use smaller ponds with more shrimp per square meter. They put aerators in the ponds so there is more oxygen in the pools, and the aerator’s propellers go about one meter deep. Intensive farmers have to feed the shrimp krill that have been fed antibiotics because disease can spread easily in the cramped ponds. They also feed them powdered fish. In intensive farms, they have to pump in clean water all the time.

Intensive farms are a lot more expensive to run because they require so much energy, materials, and labor. Intensive shrimp farms can be very profitable, but they are more expensive than extensive shrimp farms. They make more sense in areas where real estate is expensive.

Since intensive shrimp farmers pump lots of water in and out of their shrimp ponds, disease can spread quickly from farm to farm. Some shrimp diseases intensive farmers try to protect their shrimp against are yellow head disease and white spot syndrome. Yellow head disease is highly contagious with mass mortality within two to four days. The infected shrimp get a yellow head before dying. White spot syndrome is a highly lethal disease and has a 100% mortality rate. Before dying, the shrimp’s digestive tract turns red, and they get white spots on their head. Farming shrimp can be risky, not only because of disease, but because of an entire crop can be lost in a flood. When we were touring shrimp farms around Hoi An, our guide told us that a recent flood rose over the walls of the shrimp ponds. The shrimp were washed downstream. Some were caught by lucky fishermen, but the farmers lost everything. Many shrimp farmers started farming rice instead of shrimp. Rice farmers earn less profit, but rice farming is not as risky.

Shrimp farming can have a negative impact on the environment, so governments are beginning to regulate shrimp farms. In the recent past, many Vietnamese shrimp farmers were creating salt water ponds inland. When the shrimp farmers pumped their salty waste water into rivers and canals, it mixed with the fresh water that other farmers used for watering their crops. The salt water killed the crops. It is now illegal to farm shrimp inland in Vietnam. Extensive farmers have cut down a lot of coastal trees, especially mangrove forests, which were seen as land with little value. Now we know that mangroves can stop erosion from floods and devastating storms like typhoons. Mangroves are also a natural nursery for fish and shrimp. The fishermen suffer reduced catches when mangroves are cut down. Now shrimp farmers are encouraged to replant mangroves along and inside their shrimp farms. When we visited Cat Ba Island, in Ha Long Bay, we saw shrimp farmers planting mangroves in their farms. A few years before their farms had been wiped out by a typhoon. Now the farmers are building eco-friendly shrimp farms in mangroves. In the future, I hope that all farmers will create shrimp farms that are actually good for the environment.

Shrimp and rice are used in many dishes of Vietnamese cuisine. Shrimp is used to add a little flavor to bland food. Rice is used in almost every meal, usually more than once. Vietnam is very fortunate. Its geography, climate, river deltas, rainfall and coastline do make it one of the world’s biggest (for its size) food producing countries. Many countries can’t feed their own population; much less feed others as well. With the world population rising so fast, the rest of the world depends on Vietnam’s harvests of rice and shrimp.