Tag Archives: corn

Archaeologists track down the earliest use of maize in the Mesoamerican area

Maize is perhaps the most important crop ever domesticated by people. Enter any shop today and you’re almost guaranteed to find a myriad of products, from sweets and tacos to cereal and of course, canned corn.

According to new research, we owe this corny abundance to the Mesoamerican settlers who started eating and domesticating corn about 6,700 years ago.

Maize, an ancient food source, was first cultivated in the Maya lowlands. Credit: UNM

Much of the popularity of maize is owed to its high carbohydrate and protein value. Maize is high in valuable nutrients and cherished globally today — but it wasn’t always this dominant. Nine thousand years ago, maize was still a humble plant with few connections to mankind.

To unravel corn’s remarkable journey, Archaeologist Keith Prufer and colleagues from half a dozen universities looked at the bones and teeth of 52 skeletons in the Mesoamerican region.

The study wasn’t specifically looking for corn. The team involved a large number of researchers from different fields including biology, geology, and of course, archaeology. Originally, the researchers wanted to get a holistic view of how these early settlers changed and adapted to a completely new lifestyle.

They carried chemical and radiocarbon measurements on the skeletons, looking for any clues about what these people ate and how they lived.

The oldest remains date from between 9,600 and 8,600 years ago, while the newer ones are about 1,000 years old. When it came to diets, there was a visible transition between the older and the newer skeletons. While the older ones foraged on wild plants, palms, fruits, and nuts and hunted for meat, the newer generations showed a strong transition to farming, the researchers show.

“One of the key issues for understanding these changes from an evolutionary perspective is to know what the change from hunting and gathers pathways to the development of agriculture looked like, and the pace and tempo of innovative new subsistence strategies. Food production and agriculture were among most important cultural innovations in human history,” says Prufer.

Ancient maize cob from Barton Creek Cave. Credit: Jaime Awe

Farming maize paved the way for the Maya civilization

Farming is quite possibly the most impactful change in human history. We take it for granted today, but it completely changed our lifestyle and set our species on a course for what we see on the planet today. It was farming that allowed our ancestors to settle in one place and start building larger settlements. But it wasn’t a straightforward change. The diet of early farmers was far less varied and healthy than that of hunter-gatherers, and it took millennia before mankind could truly reap the benefits of farming.

“Farming allowed us to live in larger groups, in the same location, and to develop permanent villages around food production. These changes ultimately led in the Maya area to the development of the Classic Period city states of the Maya between 3,000 and 1,000 years ago. However, until this study, we did not know when early Mesoamericans first became farmers, or how quickly they accepted the new cultigen maize as a stable of their diet. Certainly, they were very successful in their previous foraging, hunting, and horticultural pursuits before farming, so it is of considerable interest to understand the timing and underlying processes,” Prufer added.

By 4,700 years ago, Mesoamericans started consuming maize. The isotopic signature of two young nursing infants shows that their mothers were already consuming substantial amounts of maize, and consumption steadily increased over the following millennia, as people transitioned more and more to a static lifestyle.

Some 700 years later, a full transition to farming had occurred, judging by the amount of maize people were apparently consuming.

“We can directly observe in isotopes of bone how maize became a staple grain in the early populations we are studying. We know that people had been experimenting with the wild ancestor of maize, teosintle, and with the earliest early maize for thousands of years, but it does not appear to have been a staple grain until about 4000 BP. After that, people never stopped eating corn, leading it to become perhaps the most important food crop in the Americas, and then in the world,” Prufer adds, noting that the first use of corn may have been in the form of liquor.

Excavations were directed by UNM Professor Keith Prufer along with an international team of archaeologists, biologists, ecologists and geologists. Credit: UNM

The teosintle that Prufer mentions is the original maize — a wild grass growing in the lower plains of the Balsas River Valley in Central Mexico. Archaeologists have found evidence that maize was cultivated in the Maya lowlands some 6,500 years ago, but there was no evidence that maize was a staple at the time.

This is why archaeologists often resort to such varied studies: on one hand, you look at people’s environments and see what changes they made to the land, and on the other hand, you look at the humans themselves and see how they changed.

In a way, the life of a modern archaeologist is a lot like that of a forensic investigator — it’s no longer about finding the pyramids and ruins, it’s about understanding how people’s lives evolved through time.

It’s rarely easy. In this case, archaeologists had to work in conditions that many would consider unbearable.

“We did five years of fieldwork in two very remote rock shelter sites in the Bladen Nature Reserve in the Maya Mountains of Belize, a vast wilderness area that is a two-day walk from the nearest road. To work in this area we had to camp with no electricity, running water, or even cell service for a month at a time each year,” Prufer adds.

The study has been published in Science Advances.

Air pollution from corn kills thousands of people each year

The pollution is produced by fertilizers and highlights how agriculture is also a significant contributor to air pollution. Corn alone is responsible for killing 4,300 Americans each year.

Turns out, maize can be a silent killer.

We all know that air pollution kills people. We also have a general idea of what causes air pollution: burning fossil fuels is chief among the causes, wildfires and waste also major issues, but agriculture is often overlooked.

“You think air quality and you think coal plants, and you think dirty diesel trucks,” says Jason Hill, an engineering professor at the University of Minnesota and the study’s lead author. “Certainly both of those are major contributors to reduced air quality, but corn production? Yes, that too.”

A few months ago, Hill published another study which found that agriculture is responsible for around 16,000 air pollution-related deaths a year in the US alone. Now, he and his colleagues have turned their eyes towards corn, the most popular US crop.

“We show that reduced air quality resulting from maize production is associated with 4,300 premature deaths annually in the United States, with estimated damages in monetary terms of US$39 billion (range: US$14–64 billion). Increased concentrations of fine particulate matter (PM2.5) are driven by emissions of ammonia — a PM2.5 precursor — that result from nitrogen fertilizer use,” the study reads.

The team created a life-cycle assessment of corn crops, which includes all stages of production. They found that 86% of corn-related pollution was generated directly on farmland, most of which can be traced directly to the use of synthetic nitrogen fertilizers. Nitrogen is essential for corn, but because the plant can’t produce its own nitrogen, it draws it from the soil via symbiotic bacteria. In time, the nitrogen is drained from the soil and must be replaced artificially.

The most popular nitrogen fertilizer is ammonia, which converts into nitrate once it enters the soil — a compound that plants can absorb. But some ammonia also escapes the soil and rises into the atmosphere as a gas. Once it does this, it contributes to the fine particulate matter that can cause serious issues to human health. The scientists traced the pollution to its source thanks to the fact that fine particulate matter doesn’t tend to travel much.

If you want to help with this issue, you shouldn’t focus on eating less corn — but rather on eating less beef. Each year, around 90 percent of the corn we grow goes to feeding livestock and producing ethanol, and the US government heavily subsidizes corn production for these purposes. The country is also the world’s largest exporter of corn.

Researchers want to carry out this type of study for different types of crops, to ultimately “the air quality impacts of all the foods we consume.”

The study was published in Nature Sustainability.

Wheat crop.

The world’s farms are dominated by only four crops

Crop fields around the world are becoming increasingly uniform, and that’s a problem.

Wheat crop.

Image via Pixabay.

The world as a whole is increasingly narrowing agricultural production to only a few crops and lineages according to new research from the University of Toronto (UoT). This not only impacts the contents of our plates, but also makes global food production less resilient against pests and disease.

More of the same

“What we’re seeing is large monocultures of crops that are commercially valuable being grown in greater numbers around the world,” says lead researcher Adam Martin, assistant professor of  ecologist in the Department of Physical and Environmental Sciences at UoT Scarborough.

“So large industrial farms are often growing one crop species, which are usually just a single genotype, across thousands of hectares of land.”

The team worked from data recorded by the U.N.’s Food and Agricultural Organization (FAO), quantifying which crops were grown on large-scale industrial farms globally from 1961 to 2014. While crop diversity in each region has increased — North America, for example, now grows 93 different crops, whereas the 1960s it was only 80 crops — it has gone down on a global scale. Large scale, industrialized farms in Asia or Europe, for example, are looking more and more like those in North or South America.

Soybeans, wheat, rice, and corn occupy just under 50% of the planet’s agricultural lands, the team reports. The rest is divided among 152 different crops. There is also very little genetic diversity within individual crops. In North America, six individual genotypes comprise about 50% of all corn crops, the team explains.

The 1980s saw a massive peak in global crop diversity as different types of plants were being sowed in new places on an industrial scale. This peak had largely flattened by the 1990s, and crop diversity across regions have declined ever since.

So, why is this a problem? Several reasons. The first is that it affects global food sovereignty, the team explains.

“If regional crop diversity is threatened, it really cuts into people’s ability to eat or afford food that is culturally significant to them,” says Martin.

Secondly, it’s also an ecological issue. If farms are dominated by a few lineages of crops, that makes the global food supply extremely susceptible to pests or diseases. All bananas (that we cultivate) today, for example, are clones —  they’re all genetically identical. And they’re being wiped out by the Panama disease, a fungicide-resistant fungus.

Martin hopes to expand his research to look at patterns of crop diversity in the context of individual nations. He says there’s a policy angle to consider, since government decisions that favour growing certain kinds of crops may contribute to a lack of diversity.

“It will be important to look at what governments are doing to promote more different types of crops being grown, or at a policy-level, are they favouring farms to grow certain types of cash crops,” he says.

The paper “Regional and global shifts in crop diversity through the Anthropocene” has been published in the journal PLOS ONE.


Researchers hack corn to grow fatter and absorb more carbon dioxide

An international team of researchers wants to level up corn by boosting its ability to capture CO2 from the atmosphere.


Image credits Juraj Varga.

Corn (or maize) is a fruit and one of the most important staple foods on the planet, exceeding even rice or wheat in quantity grown per year. However, in Australia, while corn has the widest geographical spread of all field crops, it lags behind its counterparts (such as wheat or rice) in yield.

One of the main issues maize has to grapple with in the land down under are harsh environmental conditions. In a bid to help the crop bloom to its full potential, an international team of researchers has been toying with its genome, to boost the plant’s ability to photosynthesize.

Sunny maize

“We developed a transgenic maize designed to produce more Rubisco, the main enzyme involved in photosynthesis, and the result is a plant with improved photosynthesis and hence, growth. This could potentially increase tolerance to extreme growth conditions,” said lead researcher Dr. Robert Sharwood from the ARC Centre of Excellence for Translational Photosynthesis, led by The Australian National University (ANU).

While all plants rely on photosynthesis to capture carbon dioxide from the atmosphere, they go about it in different ways. Plants like wheat and rice use an older and less efficient photosynthetic path (the ‘C3’ path), while other plants such as maize and sorghum use the more efficient C4 path.

Some of the most important food crops today (as well as many that are used for animal feed and biofuel production) rely on the C4 pathway. C4 plants are specially adapted to thrive in hot and dry environments — ones that are expected to be more prevalent in future decades.

“There is an urgent need to deliver new higher-yielding and highly adapted crop species, before crops are affected by the expected climate change conditions. These conditions will increase the threats against global food security, and the only way to prepare for them is through international research collaborations.”

One of the molecules that underpins photosynthesis is an enzyme known as Rubisco — which converts CO2 into organic compounds. Rubisco’s activity is much improved in C4 plants, making the process faster and more water-efficient. As a result, these plants are more tolerant to heat and drought, and tend to be more productive than their C3 counterparts. Maize has one of the most efficient Rubisco enzymes and uses “less nitrogen” to grow than other crops.

“So, our main question was, if we increase Rubisco content in maize, what would it do for the plant?” says co-author David Stern, from the Boyce Thompson Institute.

“We found that by boosting Rubisco inside the maize cells, we get an increase in crop productivity,”

Overall CO2 assimilation and crop biomass increased by 15%, the team reports. While quite excited with their results so far, the researchers plan to further increase the “pool of active Rubisco” in the plant to increase this percentage even further. Until then, however, they hope to pit their maize against real-field conditions — the crop has, thus far, only been tested in glasshouse and cabinet conditions.

However, if the team’s maize proves itself hardy enough to survive farmland, it could pave the way for further C4 crop species to receive the same treatment.

The paper “Overexpression of Rubisco subunits with RAF1 increases Rubisco content in maize” has been published in the journal Nature Plants.

Bug-Killing Corn Mostly Benefits Conventional Crops

I’m really not sure what to think about genetically modified food; in theory, it seems like one of the best ideas ever, but if we don’t fully understand the ramifications of the modifications, it can have really harmful effects. But still, the study I’m going to tell you about is not that. It’s about the effects bug killing korn has (that’s a great name for a rock album, by the way).

The corn was genetically modified to produce an insecticidal protein called Bt that had remarkable results: it reduced damage done by corn-borer (corn’s biggest enemy) by 20-70%. Overall, since the introduction of this protein 14 years ago, farmers only from Illinois, Iowa, Minnesota, Nebraska and Wisconsin reported a benefit of almost 7 billion dollars.

But what’s really interesting is that most of this benefit was reported from traditional non-modified corn, which was able to grow in less stressful conditions, without the stress of insects.

Corn borers

“That’s sort of the wow factor,” Bill Hutchison, the head of entomology at the University of Minnesota and lead author of the study, said in a telephone interview. “We didn’t realize until we started really adding it up over 14 years that that two-thirds of the benefit is on the non-Bt corn acres.”

Every farmer who uses Bt protein corn is required by law to plant at least 20 percent regular corn to prevent bugs from developing a natural immunity to the pesticide; so since Bt corn farmers plant conventional corn to, they also feel the residual effect the protein has. But even if the corn borers are facing their darkest days, they can still be a danger in years to come.

“Farmers are asking, ‘If populations are low, do I still need to pay for this Bt technology?’” Hutchinson said. “Our models also show that if they just stopped planting Bt corn, in about 4 to 5 years the corn borers probably would come back.”

High-fructose corn syrup – the mastermind behind obesity?

hfcsWhether you want to admit it or now, the world (and most of all America) has a problem with obesity. The fact that people are eating less healthy and working out less is something that can’t be denied even by the most optimistic of us. However, even taking into consideration all those aspects, the numbers seem to be unbelievable. About 1 in 3 Americans is obese, and under 1 in 3 has suitable weight.

What if it’s that high fructose corn syrup (HFCS)? It was introduced in 1970, about the time obesity began to take proportions, and it’s very possible that it has a certain trait that wreaks havoc into your cells, especially fat cells. When it was introduced, it was a huge success, and it took many “client” from sugar; you can check out all those things and many more from HFCSfacts, which was dedicated exclusively to sharing information about it.

What’s surprising is that almost nobody seems to be paying attention to this really important issue. Just taking into consideration all the health issues caused by obesity (not to mention the huge productivity loss) should be enough motivation for several studies to be carried to find out for sure if there is a connection between HFCS and obesity.

“A number of recent studies . . . have convinced me that HFCS does not affect weight gain,” says Barry Popkin of the University of North Carolina, who was an early proponent of the HFCS-obesity hypothesis. “At the same time, there is a new body of research that suggested HFCS might be linked with higher triglyceride levels and other health effects. This research is too preliminary to make any conclusion.”