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The fate of food August 2nd, 2020 by

In The Fate of Food, Amanda Little (professor of journalism and science writing at Vanderbilt University) takes us on a strange journey to the cutting edge of agricultural research. Little has an astonishing knack for getting quality face time with some of the most innovative (and busy) people in the science of food.

She takes us to Shanghai to meet Tony Zhang, an entrepreneur who dreamed of being the Whole Foods (grocery store chain) of China. Zhang was so enraged when he found out that his vegetable farmers were growing special plots of organic produce just for their own families, while selling produce tainted with pesticides, that he created his own 4,000 hectare farm where he monitored his crops with electronic soil sensors that captured data on soil moisture and temperature, humidity, acidity and light absorption. The cost of managing the data and cleaning the heavily polluted soil eventually led Zhang to quit farming, but other companies continue to improve his idea of the digitalized soil sensors.

In Silicon Valley, Indian cardiologist Uma Valeti leads a startup that is culturing meat in the lab. It’s real meat, just grown in a Petri dish, not in an animal’s body. Little finds the duck meat tasty, although at over $100,000 a serving, it’s still not commercial. But costs are falling.

In Norway, commercial salmon grower Alf-Helge Aarskog is growing the fish in cages in the seawater of a fjord. Fish farmers are racing to invent technology fast enough to solve their emerging problems. Captive salmon were once fed wild sea creatures, but the diet is now 75% grain, with the goal of creating a completely vegetarian, cultivated fare. The dense populations of penned fish are a breeding ground for “sea lice,” a crustacean parasite of salmon. Aarskog is using a robot that can spot the sea lice and zap them with a laser as the fish dart through the water.

Robots are the newest farm workers on dry land as well. Peruvian engineer Jorge Heraud and colleagues in California have invented a “lettuce bot” that can thin a field by recognizing when seedlings are too dense, and kill the extra plants with a precision over-dose of chemical fertilizer. John Deere sees enough promise in the idea that the corporation recently bought Heraud’s company for $305 million.

In the USA, most lettuce is grown in California in the summer, and around Yuma, Arizona in the winter, a continent away from the big consumer markets of the East Coast. Former Cornell professor Ed Harwood and colleagues have solved this problem by growing aeroponic lettuce in an old building in Newark, New Jersey, where the plants grow under LED lights, without soil. The lettuce is marketable after 12 to 16 days instead of 30 or 45, and the plants yield four times as much as in the open field. The lettuce is grown on trays stacked high, so the yield per hectare can be 390 times as high as in a conventional farm.

The book is crowded with insights. For example, drip irrigation was invented in the 1930s by Simcha Blass, an Israeli engineer, after he observed a tree growing big and lush in the desert, thanks to a nearby, overlooked leaking faucet. Little is also cautious about some recent innovations; 90% of the maize, soy and cotton grown in the USA now is genetically modified, mostly to be grown with high doses of herbicides. Pigweed has now evolved resistance to the herbicides and infests 70 million acres (28 million hectares) in the United States.

As we learned from professor Calestous Juma, earlier in this blog (The enemies of innovation), innovations often look awkward at first; it took years for the farm tractor to become agile enough to really compete with horses. It’s hard to tell which of the innovations that Little describes will produce the food of the future. But big data, robots and more indoor farming may all be here to stay. Little starts and closes her book with a vignette about Chris and Annie Newman, a young couple in Northern Virginia raising pigs and chickens, and fruit and nut trees, with permaculture. The Newmans are pro-environment and pro-technology; they look forward to the day when they can use weeding robots on their farm. It’s just possible that digital technology of the future might tempt more young people to invest in highly productive, organic family farming.

Further reading

Little, Amanda 2019 The Fate of Food: What We’ll Eat in a Bigger, Hotter, Smarter World. New York: Harmony Books. 340 pp.

The problem with water hyacinth November 17th, 2019 by

The Pantanal wetland, shared by Bolivia and Brazil, is the size of a small sea. In the Pantanal it rains for six months, followed by a half year drought. During the rainy season the rivers overflow their banks, creating a seemingly endless sheet of shallow water reaching to the horizon. In the dry season the water retreats to the river courses. There are few trees in the Pantanal, but there are dense stands of a delicate-looking purple flower, the water hyacinth.

In the twentieth century, gardeners innocently spread the water hyacinth to Asia, Africa and elsewhere. Water hyacinth has striking blue flowers and was used to adorn ornamental fountains. But it escaped and was soon clogging lakes, ponds and municipal water supplies.

Water hyacinth is such a survivor that you can drain ponds, let the plants dry out and burn them – then watch them grow again when the pond is refilled. It’s not surprising that control options are limited, particularly in open water, such as lakes and rivers.

The plants can be hand removed, by people willing to do heavy labor in the mud, cutting and dragging water hyacinth to the shore. Even this drudgery only works if you repeat it every year.

When the water hyacinth is removed, people tend to leave it in heaps at the edge of the water, where it is unsightly and gets in the way.

I recently saw another solution for water hyacinth in Benin, in West Africa. At Songhai, a training center in Porto Novo, they harvest water hyacinth, chop it, mix it with manure and use it to make methane (biogas) for cooking. Songhai also keeps a large tank of methane to run an electrical generator when the power is out.

Making biogas isn’t for everyone, as we saw in a previous blog. The Moreno family in Peru has trained people for years to make biogas from guinea pig manure, but few if any of the trainees later made biogas at home. For this to happen you need to buy equipment, provide labor, and pay close attention to managing the microorganisms that ferment the organic matter and give off the gas.

I liked the Songhai method because they don’t just remove the water hyacinth. They treat it like raw material and they make something with it.  But I wondered if using it to make biogas was profitable. A more detailed study is needed to gauge its potential to make money. The Songhai solution has one key advantage: the water hyacinth does not need to be dried, a plus because the big heaps of flesh plants hold retain a lot of water.

Water hyacinth is a water thief in some of the thirstier parts of the world. Finding uses for it may help to defray the costs of weeding it out.

Related blog story

The guinea pig solution

The juice mobile

Harsh and healthy

Floating vegetable gardens


Learn how to use water hyacinth to make a floating garden

Floating vegetable gardens

Learn how to make biogas

Zero-grazing and biogas

Scientific name

Water hyacinth is Eichhornia crassipes.

Robbing land from the sea March 25th, 2018 by

The low-lying Netherlands is famous for its polders, the land behind the dikes, reclaimed from the sea. Beginning about 1000 AD, people made dikes, or earthen dams, to protect communities from flooding. At first the water was simply drained through canals, but with time the land in the polders subsided, and by the 1400s water was being pumped out with windmills. Thanks to hard work, investment and some clever engineering, people still live in and farm the polders.

Much of Bangladesh is also right at sea level and densely populated. So why doesn’t Bangladesh have polders too? I wondered out-loud during a recent visit last October.

“But we do! Bangladesh has many polders,” my colleague Salahuddin retorted. He explained that there was a string of some 123 polders over much of southern Bangladesh, an area where several large rivers cut the delta into finger-like strips of lowland.

The polders were built between the 1960s and the 1980s, first by the provincial government of East Pakistan, and later by the Government of Bangladesh, after independence from Pakistan in 1971.

Each polder is ringed by a low earthen embankment (basically a dike), sometimes just two meters high and made by hand. The roughly oval-shaped polders are dozens of kilometers in circumference.

The Bangladeshi polders are drained by an ingenious network of canals, radiating like veins from the center of the polder to the edge, where the flow of water is controlled by a sluice gate in the embankment.The sluice gate is a concrete structure with metal doors that can be raised by a hand-crank to let the water out during the rainy season, and lowered during the dry season to keep out the saltwater.

Originally the wetlands of the delta region had been sparsely populated by fisher-farmers who grew low yielding rice varieties that tolerated brackish water. The polders soon became attractive places to live and settlers trickled in. The people who were born in the polders tended to stay there and so populations increased.

Some of the polders have benefited from some sort of project, and have been reasonably well managed. By 2018 the better polders are like gardens, with comfortable farm houses surrounded by shimmering green rice fields.

The polders have had their share of troubles. Sometimes one of the rivers changes course, depositing a bank of silt next to the sluice gate, so the water inside the polder cannot drain out.  Other problems are man-made. Loggers float timber down the canals, and when the logs reach the sluice gates, the workers take the easy route to the river. Instead of hoisting the logs around the sluice gate, the loggers force the timber through the delicate metal gates, twisting and denting them so they no longer open and close. Wealthy, powerful people sometimes block the drainage canals to raise fish in them. Or they string nets over the canal to catch fish. But this slows down the flow of water, allowing silt to settle and eventually block the canal. The canals are as wide as a highway, and can be just as difficult to maintain. So once the drainage canal stops working, villagers are unable to open them up again without help from outsiders.

The polders are essentially a government mega-project, which sounds at first like a recipe for disaster. But as one drives along the top of a polder embankment, the muddy river on one side and the tidy green fields and villages on the other, it is hard to ignore the fact that the government got something right.

Ironically, country that is flooded during the rainy season may be completely dry a few months later. Various initiatives are now promoting dry-season irrigation for high value crops besides rice, and the farmers in the polders are avidly buying motorized pumps. In many places the rich, black earth inside the polders is now producing two or three crops a year of rice, mung beans, mustard, watermelon and vegetables.

Such changes in the farming system are creating more wealth for the farmers in those polders that are well run. But it will take collaboration, for local government to protect the canals and embankments, for the private sector to provide farm supplies and buy the produce and especially for innovative farmers, to continue re-inventing the agriculture of this marvelous, human-made environment.

Further reading

In characteristic modesty it was some time before my friend Salahuddin told me that he had written his masters’ thesis on the polders of Bangladesh.

Salahuddin, Ahmad 1995 Operation and Maintenance of Small Scale Flood Control Projects: Case of Bangladesh Water Development Board. Master’s Thesis: Institute ofSocial Studies, The Hague.

See also Paul’s blog from last week on coastal Bangladesh: Floating vegetable gardens.


I am indebted to Md. Harun-ar-Rashid, Guy Jones and many others for enlightening me about polders on a recent trip to Bangladesh, supported by the Blue Gold Program, with funding from the Embassy of the Netherlands. Thanks to Harun-ar-Rashid, Ahmad Salauddin, Paul Van Mele and Eric Boa for reading and remarking on previous versions.

Fishing changes November 12th, 2017 by

Two million years ago in East Africa, long before humans lived on any other continent, our ancestors followed the receding shorelines of shallow ponds and lakes, during each annual dry season, scooping up the stranded catfish and eels. People have eaten fish ever since, and fishing may have shaped humans more than big game hunting.

From Rome to China, early civilizations would have been impossible without fish, as renowned archaeologist Brian Fagan tells us in a new book, Fishing. Mesopotamians could always rely on fish, even when the flooding Tigris and Euphrates failed to water the crops. When the Nile flooded, it covered the land in fish, as well as water. The pyramids of Egypt were built by laborers fed on rations of beer, bread and dried catfish, caught every year in the shallow, receding flood waters of the Nile.

Ancient sailors in small boats could not carry enough provisions for long voyages. The mariners would never have been able to explore the Indian Ocean and create the trade routes that linked Europe and Asia, without settled communities of fisherfolk, who caught and dried fish to sell or trade.

Fishing would have been impossible without local knowledge. The Tahitians sailed sophisticated, deep-sea canoes to catch large, predatory fish. The big fish and the sea birds both followed dense schools of smaller fish. The Tahitians recognized that the big fish followed the birds to find the small fish. Fishers scanned the horizon for birds, and could tell by the species flying over the water what type of fish to expect there.

Commercial fishing began with herring in the North Sea in the 1300s. Dutch and Flemish crews caught the fish from deep-water wooden ships called busses, which required a large crew and started the season every year on the night of St. John, 24 June. The fish were salted, packed into standard-sized barrels, branded with the seals of the merchants who sold them, and traded all over Europe until 1810. By then the herring were becoming scarce, and salted cod from the Atlantic had captured the market. While there is still fishing in the North Sea, before the 1800s the herring were so abundant they were compared to ants.

As waters were fished out, fishers sailed farther and farther from home. The English were fishing off the shores of Iceland in 1420 and off the banks of Newfoundland in 1600. By about 1880, new technologies such as steam trawlers extended the reach of commercial fishing to deep ocean water. But some modern techniques are devastating, such as the large nets that drag the bottom, destroying the places where the fish spawn.

Many countries have reacted to over-fishing by creating 200-mile exclusion zones and limiting catches. The Canadian government closed the cod fishery in 1992 when stocks hit 1% of their peak. Thanks to the ban, the cod have since partially recovered.

Although subsistence fishing is ancient, it has never destroyed the fishery it depended upon. Salmon and sturgeon once swam up the Danube River to spawn. Communities of fishers had survived for thousands of years at the Iron Gates (on the Danube between Serbia and Romania), until nineteenth century pollution, dam-building and over-fishing destroyed the stocks.

But waters far from home, as in the Antarctic, are uncontrolled and fished recklessly, as though there were no tomorrow. Commercial fishing is now in a slow decline, while artisanal and subsistence fishing are both on the rise. Fish farming is increasing rapidly. By 2012, for the first time in history, more fish were farmed than caught wild.

I saw a glimpse of artisanal, peasant fishing recently in Bangladesh, where many villages have fields interspersed with fish ponds. Farmers throw nets and use various other techniques, bringing home one small bag of fish at a time for the supper pot.

On one especially rainy day, the ponds were over-flowing, and some people were setting up long, gently tapering nets over the drainage ditches, to catch any fish that may have escaped from the ponds. No fish was going to be wasted.

Subsistence fishers are often smallholder farmers. Fishing and farming combine easily. If fishing fed civilization, as Fagan explains, it is the smallholders who will keep fishing alive into the future. The fish ponds in Bangladesh are highly commercial, run by knowledgeable farmers. With the increasing demand for proteins, fish species will continue to feed humanity only with a good balance between open sea fishing that respects quotas (based on science and policy) and fish farming that will require stringent food safety measures, such as guarding against the abuse of antibiotics.

Further reading

Fagan, Brian 2017 Fishing: How the Sea Fed Civilization. New Have: Yale University Press. 346 pp.

Related blog stories

Cake for fish? hold the coconut, please

Fishing on a hill

Further viewing

Food for fish

Stocking fingerlings in a nursery pond

Preparing low-cost concentrate feed

Growing azolla for feed

Cake for fish? Hold the coconut, please November 6th, 2016 by

cake-for-fish-1A good farmer training video inspires farmers to modify practices, for example, replacing an ingredient of a locally-made animal feed. But when changing ingredients, one has to know a lot about them, as we learned recently while teaching a video production workshop in Tamil Nadu, southern India.

Explaining the principles behind a certain technology or why something is done in a particular way helps farmers to better understand the innovation and to try it out with whatever resources they have at hand. The different examples shown in a video help to give farmers more ideas to work with.

In Tamil Nadu, one group of trainees was making a video on home-made animal feed, which only costs half as much as concentrated feed that one can buy in a shop.

cake-for-fish-2By interacting with various farmers, the trainees learned quite a few things. While shops sell specific feed for different animals, farmers make a base mix of grains, pulses and oil-cakes that they use to feed all their animals and fish. This saves the farmers time, while allowing them to still tailor the feed for each species of livestock. Depending on whether it is for cattle, goats, poultry or fish they will then add some extra ingredients, like dried fish (if the feed is for fish or poultry).

The trainees also learned that when you want to use a base mix for fish, you need to consider a few things. Farmers rear up to 6 different species of fish. Two species are surface feeders, two feed in the middle layer, and two species are bottom feeders. As you want the feed to be eaten by all fish, the mix should be milled to a course flour. When ground too fine, the feed will float and be available to the surface feeders only.

One other thing the team of trainees learned was that for fish you can use groundnut oil cake or cotton seed oil cake, but you should never use coconut oil cake (which is readily available and cheap in coastal India). Why? Well, if coconut oil cake is used in the base mix, two days after feeding the fish, an oily film will develop, blocking the pond from sunlight and oxygen and slowly killing the fish. The household can still use coconout oil cake in base feeds intended for livestock.

Clearly, oil cakes are not all the same and not all are interchangeable.

Good farmer training videos should present a range of different options and locally available resources, but they should also warn farmers of any possible risks. Videos for farmers should always say why an option will (or won’t work), as in this case: don’t feed coconut to your fish or the oil will block their sunlight and kill them!

Related video

Preparing low-cost concentrate feed

To watch the video in French, click here.

To watch the video in Tamil, click here.

To watch the video in Bangla, click here.

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