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Salt-Loving Super Plants: Saviors of the Planet?

Oct 31, 2014 09:41 AM EDT
Deluge, droughts, rising sea levels, and shrinking water tables - these are the things of nightmare for farmers and agriculture scientists alike. That's because they know something that most of us don't think about: the world's demand for food is set to increase by two-thirds by mid-century. That's where salt-loving plants, called halophytes, can make a difference.
(Photo : Flickr: Bob Richmond)

Deluge, droughts, rising sea levels, and shrinking water tables - these are the things of nightmare for farmers and agricultural scientists alike. That's because they know something that most of us don't think about: the world's demand for food is set to increase by two-thirds by mid-century.

And while the impacts of that heightened demand might not be immediately felt by the citizens of food-fat world powers, the farmers of already struggling countries are shaking in their boots. That's because for countries along the African coasts and in the Middle East, their farmland already boasts declining yields year-by-year.

Waning Water

Nature World News has reported in the past about some of the causes of this alarming trend. A study published just last July in Environmental Research Letters details how East Africa is heavily reliant on irrigation to grow crops, but is still extremely deprived of adequate irrigation systems compared to the rest of the world. In fact, the study of sub-Saharan Africa revealed that only about four percent of cultivated land is irrigated. The global average, for comparison, is 18 percent.

What's worse, climatologists are speculating that this same part of the world is due for a dangerous shift in precipitation patterns, becoming even more arid and water-deprived than it already is.

Meanwhile, in parts of the Middle East, their characteristically dry landscapes are becoming more parched than ever before. That's because, as populations and urbanization increases in these areas, the ground water table is being drained faster than yearly rainfall can refill it. The situation is worst for Iran, which is losing so much water that its iconic Great-Lake-sized bodies of water - once home to party boats and great flocks of flamingos - are now nothing but muddy puddles.

This is in part because Middle-Eastern agriculture needs extensive irrigation as well to keep their farms alive. (Scroll to read on...)

(Photo : Flickr: Orin Zebest)

Salting the Earth

However, even as increasingly strict water rationing is being implemented by these affected countries, their poorly managed irrigation is not only sucking the ground dry, but poisoning it as well.

That's at least according to a UN University (UNU) study that found that irrigation without regular washing of cultivated land (through rainfall or other means) can lose up to 70 percent of their annual yield to salt poisoning. Researchers from Canada, Jordan, Pakistan, and Sri Lanka even found that the world is losing an estimated 2,000 hectares (~5000 acres) of irrigated farmland annually, all because salt is building in these lands and rendering their soil utterly parched, dead, and covered in a fine white crust that tells practiced farmers "nothing will grow here ever again."

"Each week the world loses an area larger than Manhattan to salt-degradation. A large portion of the affected areas in developing countries have seen investments made in irrigation and drainage but the infrastructure is not properly maintained or managed," Zafar Adeel, the director of UNU's Institute for Water, Environment and Health, explained in a recent statement. "Efforts to restore those lands to full productivity are essential as world population and food needs grow, especially in the developing world."

Adeel and his colleagues suggest using expensive fertilizer conditioners like gypsum to help reverse soil degradation. Other methods, like deep tilling and simply improved farming tactics have also been seen to boost soil productivity.

Halophytes to the Rescue

However, there is one alternative the UNU international team mentioned that is gaining a great deal of unlikely support: the halophyte revolution.

Statistics show that at least an estimated 97 percent of water on Earth contains high concentrations of salt. This locks away a great deal of our plants' most vital resource for survival and renders a great deal of coastal land unsuitable for farming.

And yet you are likely well aware that the ocean and its coasts boast their own kind of plants. That's because of the over 400,000 plant species in the world, a select 0.7 percent are called "halophytes," meaning salt-loving. (Scroll to read on...)

Salicornia is a genus of succulent, halophyte (salt tolerant) plants that grow in salt marshes, on beaches, and among mangroves.
(Photo : Flickr: RustyClark) Salicornia is a genus of succulent, halophytes that grow in salt marshes, on beaches, and among mangroves.

Now, a team of researchers have suggested in a recent paper that the best course of action for the world is to teach our most productive food crops to adapt like the halophytes - allowing for high yields even in declining or "unusable" soil.

"We suggest that we should learn from nature and do what halophytes, or naturally salt-loving plants, are doing: taking up salt but depositing it in a safe place - external balloon-like structures called salt bladders," co-senior author Sergey Shabala said in a statement. "This strategy has never been targeted by breeders and, therefore, could add a new and very promising dimension to breeding salinity-tolerant crops."

The researchers add to the UNU report by writing how soil salting is claiming about three hectares (7.4 acres) of potential farmland every minute. To overcome this, Shabala and his colleagues looked into the genetic information that causes a plant to develop a salt bladder - a remarkable outgrowth that absorbs the salt in a plant's water supply, separating it from the rest of the plant.

Past work has only revealed in theory how these bladders really work, but the genetic information that's behind them has been revealed.

"We know already about the key genes required to grow trichomes, or outgrowths of a plant. If we learn to activate those that trigger the developmental shift from an ordinary trichome to a salt bladder, one may be able to grow external salt depots on any crop," added co-senior author Rainer Hedrich.

And while that may sound like some serious tampering with plant genetics, its important to remember that most genetically modified crops are heavily monitored, with the Food and Drug Administration only allowing for eight tightly controlled GMOs in the United States. Unsurprisingly, these are the same high-yield crops - like corn and rice - that would be candidates for the halophyte solution. (Scroll to read on...)

(Photo : pixabay)

Salted Greens, Anyone?

There's another alternative, too: use the few halophytes nature already gave us. An enlightening recent feature in Aeon magazine details how, of the 2,700 or so halophytes in the world, a good portion of them are edible.

Dennis Bushnell, chief scientist at NASA's Langley Research Center, told the magazine that he's been studying the Earth and its encroaching agricultural problems for years, and he thinks that an acquired taste for the salt-loving plants could save us a great deal of trouble.

He predicts that by flooding wasted grounds with salt water and planting natural halophytes there, we could get the world's fresh-water issue under control in "15 to 20 years," reallocating fresh-water irrigation to only the most productive standard crop farmland.

"The beauty of halophytes," says Bushnell, "is you can do it wherever you have wastelands and some saline water. We have a surfeit of that."

However, Aeon science writer Mark Anderson notes that while these crops are promising, they really haven't found a stable market. And without profitability, it will be hard for the "halophyte revolution" to take off.

Jeannette Hoek, president of the company OceanDesertFood, told Anderson that fleshing out a market is slow-coming, but her company is making some headway with its assortment of seaweed crackers and pickleweed.

"As soon as the farmers see they can sell something, they will do it," she said.

But until then, people need to get talking. Anyone care for some extra-salted greens?

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