Coming Full  Circle: Integrated Farming in Vietnam

CAN THO, VIETNAM — The trail winds between rice fields, beneath the banana-tree canopy where the sunlight dances across the ground. Water droplets cling to the elephant grass after the recent rain, as if even the plants were sweating in this humidity. Wood smoke hangs in the air, and the voices of unseen people and animals drift in on the sudden breeze. As the storm clouds retreat toward the horizon, canals and dikes and fields and orchards in a thousand shades of green stretch out around us. The people here in the Mekong Delta of Vietnam use every inch of land and water. Nothing goes to waste.

The trail makes a final turn and opens into a bright clearing behind the low-slung house of 58-year-old Nguyen Buu Chau. Nguyen (pronounced “nWIN”) is a farmer and member of Heifer Vietnam’s dairy project in Long Hoa village. He greets us, eager to show us his farm, a model for other farmers in the village. Nguyen’s farm is small, only a couple of acres, and this small courtyard behind the house is its center.

Nguyen, like every Heifer Vietnam project participant, practices integrated agriculture. Each farm we visit in the Mekong Delta will be different — some will have cows, some goats and rabbits, some ducks and fishponds — but they all share a similar philosophy: reduce expenses and increase productivity by finding multiple uses for everything — fields, crops, animals, water — and recycling all organic matter back into the farm.

In Search of Closure
Integrated agriculture is more than a philosophy. An integrated farm such as Nguyen’s is a living system, a set of dynamic relationships between its many parts. Fueled by what industrial farming considers waste — especially manure — the integrated farm seeks to be a closed system, capable of continuing itself indefinitely with few outside inputs and little or no waste.

After World War II, industrial agriculture, with its large landholdings, expensive machinery and chemicals, marched around the world under the banner of the Green Revolution. While it has led to greater yields, especially in developing countries, it is increasingly evident that the system is unsustainable and unfair to small farmers. It is a linear system that relies heavily on external, industry-controlled resources — seeds are bought from seed companies; fertilizers, herbicides, fungicides and pesticides from chemical companies; energy, in the form of gasoline or diesel, from petroleum companies. These merely pass through the farm, extracted at the end of the season and bound again for external markets. Money, material and fertility all drain from the farm. Everything that cannot be sold is viewed as waste to be removed and dumped. Manure is scooped, loaded, trucked and stockpiled, turning a natural fertilizer into a pollutant.

Integrated farming seeks to take the two ends of this straight-line system — the inputs and wastes — and bend them back toward each other.

Mimicking natural ecosystems, every crop, animal or garden in an integrated system serves multiple purposes. Where industrial agriculture might treat low fertility with purchased artificial fertilizers, the integrated farm returns by-products — manure or used bedding straw, for example — to the soil to increase fertility.    

Though the name may be new, the idea underlying integrated agriculture is not, especially in Southeast Asia. Japanese farmer Masanobu Fukuoka notes in his One Straw Revolution that this type of agriculture—“joining animals, crops, and human beings into one body”—went on in Asia for centuries, until the mechanization of farming after the Second World War.

“It was a system which emphasized the fundamental importance of compost and of recycling human and animal waste,” says Masanobu. “All organic residue was made into compost and returned to the fields.”

In its simplest form, the integrated system is a simple circle beginning and ending with grass (or similar feed). The grass feeds the dairy cow, which in turn provides milk and manure. The milk is a source of nutrition and income for the family. The farmer returns the manure to the field to fertilize the grass.

Nguyen’s system, even on his small farm, is much more complex.

In One End and Out the Other
This courtyard is the nucleus of Nguyen’s smallholding, with all of the farm’s operations buzzing and whirring around it like electrons. On one side of the courtyard is the new cow barn. A few steps away is the kitchen, where the milk is strained. And beyond the house flows a canal, like an artery in an intricate vascular system. Flanking the courtyard are low, brick worm bins where the chickens and ducks like to congregate. From the courtyard, a trail leads through the fruit trees and to the rice field beyond.

The barn, with concrete floor and metal roof, replaced a dirt-floor and palm-frond-roofed stable. Nguyen’s black-and-white cows are munching on elephant grass that one of his children cut from the edge of the rice field, as they do everyday.

The cow’s digestive system, with its four “stomachs,” transforms the grass first into a fermented mush and finally into muscle, milk and manure. Cows — along with goats, sheep, deer and llamas — are ruminants. Where most animals have a straightforward monogastric digestive system — food enters at the mouth, is digested in the stomach, absorbed in the intestines and excreted — ruminant digestion is more complex. After a cow chews the grass, the wet ball of food, or bolus, enters the rumen, where it will ferment, aided by microbes present there. (Think sauerkraut.) This fermentation breaks down the cellulose in plants, making more nutrients available to the cow. The cow then regurgitates this partially digested bolus, now called cud, chews some more and then swallows it again. Nguyen’s cows will spend up to eight hours a day ruminating.

When the cud is fully chewed, it passes through the reticulum and into the omasum, which reduces the particle size and absorbs some of the liquid, and then into the abomasum. The abomasum is the true stomach and, like the stomach in non-ruminants, secretes gastric juices to digest the food.

Even though rumination allows cows to extract more nutrients from the plant than most animals, 75 to 90 percent of the nutrients are not absorbed and are excreted. In the end, it all comes out in a neatly packaged bundle.

We call this gift cow manure. (Manure is technically the solid waste plus the liquid waste and bedding.) While all livestock manure is an excellent soil amendment and natural fertilizer, each type — cow, goat, rabbit chicken, fish — has its own particular properties. Dairy cow manure recycles crop nutrients and promotes healthy microbial action in the soil. But it also has many more uses.

Nguyen’s hand follows the clear tube up from a valve, tracing its arc with his forefinger until it ends at the stove. He stops, lights a match and opens the valve. Just as the sulphurous smell wafts up, the gas ignites and the blue flame races around the burner until it meets itself on the opposite side.

This stove does all the cooking for the household, where a few years ago, they would have cooked with a wood-burning stove, requiring more time and work (especially for the women) and created a health hazard. Nguyen, with a loan from a Heifer Vietnam revolving fund, installed a bio-gas unit below ground, which feeds methane to the stove. (For a complete look at bio-gas units, see the March/April issue of World Ark.)

The bio-gas unit exemplifies the genius of the integrated farm. The cow barn has a channel, several inches deep and wide, running lengthwise down the center of its concrete floor. The channel slopes gently from rear to front and disappears into a hole at the near end of the barn. This hole leads into the bio-gas unit buried beneath the courtyard. Each day, when it is time to clean the barn, Nguyen or his children sweep the manure into the middle channel, and, with a little water, wash it into the bio-gas unit, where it will slowly release methane. Only after it has released all its methane will Nguyen remove the slurry from the unit and spread it around the grass and fruit crops as fertilizer.

The "Lowly, Organized Creature"
Not all of the cow manure goes into the bio-gas unit, however. Nguyen shepherds us across the courtyard to two brick structures that look like above-ground tombs, each covered by a sheet of plywood. Nguyen squats down and slides one corner of the sheet aside, revealing what looks to be dark, rich soil. But when he turns the top layer with a stick, it reveals thousands of earthworms. Manure, it turns out, is a great medium for raising earthworms.

Writing about the earthworm in 1881, Charles Darwin said, “It may be doubted whether there are many other animals which have played so important a part in the history of the world as have these lowly organized creatures.” (Darwin’s final scientific treatise before his death in 1882 — “The Formation of Vegetable Mould through the Action of Worms, with Observations on Their Habits” — focused on the earthworm.)

As with the cow, something wonderful and mysterious happens in the gut of a worm. The worm feeds on decaying organic matter, digesting them into even smaller particles. Gardeners the world over prize earthworm castings. The castings concentrate nutrients and make them more available to plants. Like the addition of any organic material, earthworm castings also improve the soil structure.

Once separated from the castings, the worms themselves make a high-protein feed for Nguyen’s chickens and ducks. The poultry in turn provide eggs, meat and insect control. And of course, their manure, rich and high in nitrogen, fertilizes the garden. Nothing here goes to waste.

Of Pond and Pen
Traveling even a short distance in the Mekong Delta can involve multiple modes of transportation. To get to Thien An Social Protection Institute, just five miles outside of Can Tho City, we take a car past the edge of the city until the paved road abruptly ends. Then we follow a sandy footpath to the edge of the canal where a boat is waiting.

The institute’s director, Tran Bach Yen, is our escort, helping us in and out of the canoe-like boat. After the short ride upstream, the boat angles into the low hanging trees, beyond which perches a handsome house. Curious children cluster on the tiled steps and poke their heads out of the classroom. These are the residents of the Thien An Social Protection Institute, and they are all Tran’s children.

Tran, in her pressed short-sleeve blue shirt and large glasses, is a compact woman. She graduated with a law degree from nearby Can Tho University, then opened Thien An Social Protection Institute three years ago to provide a safe, stable environment for street children, AIDS orphans, child laborers, sexually abused children and heroin-addicted teenagers. Fifty children, ranging in age from 4 to 19, call the institute home. The institute offers them shelter, food, education. It even offers scholarships to promising young people, like one 16-year-old boy who is determined to study economics at a university.

Tran and her nine staff pick up where the government leaves off. With only limited resources, the government does not have effective programs for children at society’s margins, nor does it provide the institute with any money. A private individual donated the house here, situated on just more than an acre of land. The institute also partners with Heifer Vietnam.

“Heifer International helped the children here,” says Tran, “by providing most of the animals here and providing vocational training.” Training in agriculture, as well as television and small-motor repair, will help the teenagers transition into Asia’s second-fastest growing economy.

The younger children press around, grabbing our hands and laughing as they lead us around the edge of their small fishpond to the zero-grazing pen housing their goats. Several black-and-white, lop-eared Bach Thau goats, a local breed whose name means “hundred grasses”, poke their heads out in anticipation of food or attention.

Goats, like cows, are ruminants and can produce 10 pounds of manure each day. But goat manure differs from cow manure, both in its appearance and its structure. Goat manure looks like pellets, not patties (thus the colloquialism “goat berries”), and it is drier, which allows it to be applied directly to the soil or even used as mulch.

But the institute doesn’t use the goat manure as mulch. Instead, the goats’ zero-grazing pen extends over the fishpond. A zero-grazing pen houses livestock that might otherwise damage crops were they to get out. Raised on stilts with a slatted wooden floor, the pen allows the goat manure pellets to fall through into the water below and feed the fish. Because goat manure contains protein, fat and carbohydrates, it makes an excellent feed for fish like the tilapia in the institute’s pond.

Allowing fish to feed on the manure of other animals is not dirty or dangerous. In fact, there is a term for animals eating manure: coprophagia. Coprophagia occurs in many animals, including guinea pigs, hamsters, even gorillas. Far from being an unclean act, it is the ultimate in recycling.

The institute stocks its pond with tilapia, which naturally feed on detritus and rapidly turn waste into high-quality protein. The tilapia clean up all the undigested bits of food — grasses and grains — in the goat manure. Fish possess a simple digestive tract and so benefit from the partially digested bits. The high level of bacteria in fishes’ stomachs neutralizes most harmful agents. Goats are well suited for this system, since they are not susceptible to many parasites.

Tran and her children at the institute also found a way to use the fish manure. The U.N.’s Food and Agriculture Organization, in a recently published study of fish-livestock integrated systems, concluded that, “fresh fish manure is similar in its chemical composition to other livestock manures, and should be suitable for use as an agricultural fertilizer.” At the institute, the fish manure fertilizes the pond, and during the dry season, they will use the nutrient-rich water on the garden. The fish manure also encourages healthy plant growth in the pond. One aquatic plant, water spinach, is a staple of the Vietnamese diet and can also be fed to rabbits, as it is at the Thien An Social Protection Institute.

Rabbits are also coprophagic animals. But unlike the fish that feed on the goat manure, rabbits feed on their own excreta. (I use the term excreta here because it is not exactly feces that the rabbits eat.) In most animals, the cecum is a dead-end intestinal pouch with no apparent purpose. However, in rabbits it has retained its function. Small particles of cellulose-rich plant matter are diverted into the cecum where it undergoes a fermentation process, similar to what happens in a cow’s rumen. Once partially digested, the material re-enters the intestine, continues its journey through the tract and is excreted as “cecals,” soft clumps of partially digested food. The rabbits then re-ingest these cecals and, after passing a second time through the digestive tract, excrete the dark, firm pellets we associate with rabbit manure. The institute uses the manure from their rabbits in the fruit and vegetable garden opposite the goat pen.

The garden, squatting on a peninsula that juts into the fishpond, is both a source of food for the children and an outdoor classroom where they learn gardening skills and the importance of livestock in a small integrated farm. This time of year, the papayas and pomelos hang from the trees like green globes, and the breeze carries the putrid-sweet smell of ripe durian fruit. Beneath the trees, green vegetables — cabbage, cucumbers, mustard — stand in stark contrast with the dark soil.

It is here, in a corner of the garden, that we toss our fruit rinds before descending back to the boat launch. This is the compost pile where the children discard all their uneaten vegetables, fruit rinds and garden clippings. Composting works on the principal of anaerobic digestion, similar to what happens in a bio-gas unit. When organic matter, such as manure, straw, fruit and vegetable scraps, is piled high so that no air reaches the interior, it creates an environment where certain bacteria thrive. Given correct temperature and moisture, these bacteria will slowly break down the organic matter into rich, crumbly humus. The students at the institute use the compost on plants and fruit trees, where it has beneficial properties similar to earthworm castings, continually improving the soil structure and returning lost nutrients. The compost pile is the final filter in the institute’s integrated system.

The Final Straw
A tropical storm is cycling off the coast, and thunderclouds advance from the east as we pull onto the shoulder of the two-lane highway. A 20 foot-wide canal slithers alongside the road, separating us from the village of Dinh Hoa. Beyond the small houses, palm trees flap and rice fields stretch like mirrors toward the darkening horizon.

We cross the canal on a monkey bridge — two horizontal bamboo poles, one for your feet and another higher up to grasp for balance — so named because of the way the uninitiated scuttle across sideways, feet and hands sliding along the poles. Water hyacinth and water spinach clog the canal below and stabilize the bridge.

On the other side sits a modest house with a thatched roof, herbs and vegetables blanketing the yard. Danh Viet, 62, and his wife Thi Hai, 55, have reared seven children here. Their youngest is only 7 years old. The couple received a cow from Heifer Vietnam in January 2001, when the project here first began. In 2004, they received the Golden Talent Award, Heifer Vietnam’s highest honor, given to one farm each year. Their farm is a model of the integrated system. Their cows feed on the elephant grass grown along the rice fields, and they return the cow manure to the garden and fields. They also raise earthworms, fish and vegetables.

Danh motions for us to follow as his gray fedora disappears around the house. Covering a small square of land in back are rows of mounded straw, like miniature Quonset huts all aligned. Danh steps over a few rows, squats down and sticks his hand into one of the mounds. A second later he withdraws his hand and, holding it in front of him, opens it like a magician, revealing several mushrooms.

Rice straw mushrooms, familiar to anyone who has dined in a Chinese restaurant, grow well here and bring a good price. Growers collect the straw after the rice harvest, arrange it as Viet has done and inoculate it. In a few weeks, the first flush of mushrooms is ready to pick, and the straw will later produce a second crop.

Even when the rice straw can no longer grow mushrooms, it finds a further use. Rice straw, like all other plant material, contains lignin, a compound that strengthens the plant. Most animals cannot digest lignin or the cellulose attached to it, making the nutrients unavailable. However, some fungi, like the rice straw mushroom, are able to synthesize the lignin, freeing up more nutrients and creating an excellent fertilizer in the process.

Danh can use this straw as mulch, return it to the rice field or compost it for use in the vegetable garden. Even the seemingly insignificant, exhausted straw has a use, and one less piece is lost.

The rain races towards us across the rice fields, shattering their calm surfaces and dripping from palm frond to palm frond before crashing to the ground. Danh takes shelter in the doorway of his house and watches. Farmers in the Mekong Delta, where water is as ubiquitous as rice, know that the rain is part of the cycle of the farm.

This rain will water the grass that will feed the cow whose manure will grow the worms that will feed the chickens that provide the eggs. This rain will fill the pond where the fish feed on what the goats do not digest. This rain will flood the rice fields that provide the straw where the mushrooms will grow.

And when the cycle is complete, it will all begin again.