December 5, 2013 2:55 pm
To grow a crop of apples, an apple tree needs a balance of light, water, temperature and carbon dioxide. It also needs nutrients, like nitrogen and phosphorus and potassium. In nature, one of these things is always going to be in limited supply, controlling a plant’s growth. Adding more water won’t do a thing if the tree is short on phosphorus; more carbon dioxide is no use if it’s too hot. The science of crop productivity is, in a way, the science of managing limiting resources.
Modern farming techniques, such as chemical fertilizers, irrigation and greenhouses, are meant to try to control the supply of these resources. Organic farmers, who do not use chemical fertilizers, still try to manage their crops’ resources, often by spreading manure or organic fertilizers. But crop yields from organic farming tend to be lower than those from conventional agriculture. And without a steady stream of nutrients flowing from conventional farms to organic ones, says a new study by a team of French researchers led by Benjamin Nowak, organic crop yields would likely be even lower still.
In their study, Nowak and his colleagues tracked the flow of nutrients through organic farms. They found that the bulk of the nutrients used in French organic farms still ultimately came by way of conventional agriculture:
Nutrients entered the organic farms mainly through fertilizing materials (manures and fertilizers) and, to a lesser extent, through feedstuffs, fodders and straws. More than 80% of nutrient inﬂows through manures (82%, 85% and 81% for [nitrogen], [phosphorous] and [potassium], respectively) and more than 95% of [nitrogen] and [phosphorous] inﬂows through fertilizers came from conventional farming, whereas 61% of [potassium] inﬂows through fertilizers came from mineral sources. Approximately half of the fodders and straws came from conventional farming, whereas all of the feedstuffs came from organic farming.
The nutrients in the manure and organic fertilizers, the scientists say, do not exclusively come from chemical fertilizers, though much of it does. In general, roughly a quarter of the nitrogen, three-quarters of the phosphorous, and half of the potassium on the organic farms had originated at a conventional farm.
Our results suggest that organic farming strongly relies on conventional farming, especially for [phosphorus] and in the case of stockless farming. This should be of interest for future scenarios on global food production.
Organic agriculture food production rates are currently around 75 percent to 80 precent of those of conventional agriculture, but the authors suggest that, if organic agriculture takes off in place of conventional agriculture, these production rates could drop further.
“[A]ccounting for nutrient ﬂows from conventional to organic farming and, therefore, indirect reliance of organic farming on manufactured fertilizer,” the authors write, may undermine the idea of a fully organic agricultural system.
More from Smithsonian.com:
December 2, 2013 3:23 pm
Obesity is a complex problem—the result of geography, economics, culture, class, personal choice and personal genetics—and the combination of these factors has led to more than a third of American adults being considered obese. And here’s another factor in this equation: journalist Kristin Wartman writes in the New York Times that new research is showing how diets of pregnant and breast-feeding women can bias their kids towards fatty foods. When expectant or new mom’s fill their diet with junk food, she says, it can affect their baby’s brain’s chemical reward pathways and set the babies up to seek more of the same.
The tastes you grew up with, the researchers say, tend to stick with you. “This early exposure leads to an imprinting-like phenomenon such that those flavors are not only preferred but they take on an emotional attachment,” says psychologist Gary Beauchamp. Pretty much everything you do affects the structure of your brain, and food is no different. If those foods you’re exposed to as a child—either in the womb or through breast milk—are energy-dense foods, like many junk foods, your brain will adapt to those foods. Wartman:
Mothers who were fed foods like Froot Loops, Cheetos and Nutella during pregnancy had offspring that showed increased expression of the gene for an opioid receptor, which resulted in a desensitization to sweet and fatty foods. “The best way to think about how having a desensitized reward pathway would affect you is to use the analogy of somebody who is addicted to drugs,” Jessica R. Gugusheff, a Ph.D. candidate at FoodPlus and the lead author of the study, wrote in an email. “When someone is addicted to drugs they become less sensitive to the effects of that drug, so they have to increase the dose to get the same high,” she wrote. “In a similar way, by having a desensitized reward pathway, offspring exposed to junk food before birth have to eat more junk food to get the same good feelings.”
So, add another layer to the complexities of obesity, and the realization that though junk foods tastes pretty good to all of us, for some it takes a little more to hit the sweet spot.
More from Smithsonian.com:
December 2, 2013 12:20 pm
Disposable foam lunch trays may soon become a thing of the past. The Urban School Food Alliance, composed of urban school systems in New York, Miami, Orlando, Los Angeles, Chicago and Dallas, aims to make school lunches more sustainable (and, in the long term, economical, the New York Times reports. The alliance’s first step: compostable lunch trays.
The trays, made out of sugar cane rather than polystyrene, can be turned into compost along with any uneaten food scraps students leave behind, the Times reports. Although foam trays are cheaper at about 4 cents a pop, the compostable versions, which currently cost 15 cents, could potentially earn back what schools spend on them through the sale of compost. Initial trials in these six cities will keep some 271 million food trays out of landfills.
Currently, the alliance is attempting to settle on one manufacturer to supply the trays nationwide. Here’s the Times:
If a winning bidder is chosen, the other alliance members will be able to piggyback on the contract, placing their own orders without having to navigate a separate bidding process. The call for bids names all six districts and says they must all be allowed to place orders at the same price.
So far, the Times says, 21 companies have been in touch about entering the bidding process. After the compostable trays are in place, the alliance plans to move on to introducing healthier food—such as antibiotic-free chicken and pesticide-free produce—as well as less wasteful utensils and packaging.
More from Smithsonian.com:
November 29, 2013 2:30 pm
We’ve known for years—since forming the germ theory of disease—that little critters like bacteria and viruses and fungi can affect us negatively. More recently, research into the microbiome, the host of microbes that live on and inside us, has shown how their behavior can affect us in more fundamental ways, from our weight to our mood, and help make us who we are. Alongside these discoveries, it makes sense to look at how microbes work on other parts of the world that humans interact with.
The latest discovery, says the New York Times, reporting on new research, comes from the world of viniculture. It turns out that the microbes that live on grapes vary from place-to-place, and it may be these microbes that give different regional wines their distinctive flavors.
Microbes are deposited on the grape surface by wind, insects and people, and may fail or flourish because of specific local conditions such as the way the grape vines are trained. And there may be genetic affinities between particular microbial species and each variety of grape, the researchers say.
…These microbes certainly affect the health of grapes as they grow — several of them adversely — and they are also incorporated into the must, the mashed grapes that are the starting material of winemaking. Several of the natural fungi that live on grapes have yeastlike properties, and they and other microbes could affect the metabolism of the ensuing fermentation. (Several species of microbes are available commercially for inoculation along with yeast into wine fermentations.)
The researchers showed that different regions’ microbes do vary in a reliable way, but they can’t say for sure if this is the reason different wine-making regions have different flavors. If so, though, says io9, your next wine tour may seem a little more like a trip to a lab:
If the results hold true, the research has strong implications for improving grape and wine quality. Winemakers, for example, could possibly tailor their vineyard treatments, farming practices and wine-fermentation management to promote or discourage the growth of different fungal and bacterial communities. The work could also extend to other agricultural products, such as fresh fruits and produce, in which different microbial communities are associated with spoilage and shelf life.
More from Smithsonian.com:
November 27, 2013 12:23 pm
Before karaoke, spelling bees and trivia nights became nightly bar activities, New York bars used to host a different kind of fun: turkey raffles.
Turkey raffles are governed by the state now, but according to The Bowery Boys, ” in the 19th century, raffles were widely seen in saloons, a jovial excuse for men to get liquored up and throw their money in for a chance at a moderate prize. In essence, it was gambling most fowl.”
There were lots of ways you could win the turkey. One game involved rolling dice. Another involved dumping pennies on the table to see who got the most heads up. They all involved drinking. So much drinking that many pointed to these turkey raffles as the epitome of the debaucherous male. In 1914, the New York Sun rejoiced that they were declining:
It is intensely pleasing to discover that New York has advanced so far in virtue that the anxious gardens of her morals have had leisure of late to discover the turkey raffle and fulminate against it. It has long been suspected that this form of gambling was ruining men and wrecking homes. Besides, its as always a postponed peril to turkeys that had survived all the normal hazards of Thanksgiving and Christmas.
We can only imagine what the New York Sun might have thought of bars that serve jello shots.
More from Smithsonian.com: