Fighting Drought With Oranges

A few years ago, South Africa began experiencing its worst drought in 30 years. The lack of frequent rainfall devastated crop production. And as the food supply withered, most people began to lose hope. Luckily, 17-year-old Kiara Nirghin isn’t like most people.

Instead of being disheartened by the problem, the South African teen turned her attention to finding a solution. Kiara began studying the causes and effects of drought to see how she could help. “If you don’t understand the problem fully, you won’t understand whether or not your solution is effective,” she says.

While researching, Kiara came across a class of super-absorbent materials. They are used in products like diapers to soak up liquid. The teen wondered if these substances could help soil retain the moisture from the little rain that fell. Then crops would have access to water even in dry conditions. Since most of these substances aren’t good for the environment, Kiara developed her own nontoxic version made from a simple ingredient—orange peel.

A few years ago, a drought began in South Africa. It was the country’s worst drought in 30 years. Little rain fell, and crops were ruined. As the food supply shrank, most people began to lose hope. Luckily, 17-year-old Kiara Nirghin isn’t like most people.

The South African teen could have been discouraged by the problem. Instead she tried to find a solution. Kiara began studying the causes and effects of drought. She hoped to learn how to help. “If you don’t understand the problem fully, you won’t understand whether or not your solution is effective,” she says.

In her research, Kiara came across a class of super-absorbent materials. They soak up liquid in products like diapers. The teen knew that small amounts of rain fall during a drought. So she wondered: Could these substances help soil hold on to the moisture? Then crops could have water even during dry times. But most of these substances aren’t good for the environment. So Kiara came up with her own harmless version. She made it from a simple ingredient: orange peel.

South Africa is located at the southern tip of Africa. Weather across the area is typically hot and dry. But there is usually enough annual rainfall to grow corn, wheat, and other crops. The recent drought, however, has caused a decline in the production of these important foods (see Widespread Drought). In 2015, for example, corn production dropped by almost 30 percent compared with the previous year. Wheat production was down nearly 20 percent.

Kiara watched this trend and worried for her community. When crops fail, food becomes more expensive. In South Africa, 20 percent of the population already lives in extreme poverty. Famine—the widespread scarcity of food—can quickly lead to starvation.

Kiara started thinking of a scientific way to tackle the issue. “There’s not much science can do to improve rainfall,” she says. “So I started looking at the research and found that even drought-stricken areas receive some rain—it just doesn’t fall regularly.” She wondered if there was a way to capture those precious drops of water and store them in the soil. That way, the water could be released slowly over time to nourish crops even during the driest times.

South Africa lies at the southern tip of Africa. Its weather is normally hot and dry. But enough rain usually falls each year to grow corn, wheat, and other crops. That has changed since the drought began. The production of these important foods has dropped (see Widespread Drought). For example, corn production fell sharply in 2015. It was almost 30 percent less than the year before. Wheat production was down almost 20 percent.

Kiara watched this trend. She worried for her neighbors. Food becomes more expensive when crops fail. In South Africa, 20 percent of the population already lives in extreme poverty. Famine, the lack of food over a wide area, could result. And people could quickly begin to starve.

Kiara looked for a way to tackle the problem with science. “There’s not much science can do to improve rainfall,” she says. “So I started looking at the research and found that even drought-stricken areas receive some rain—it just doesn’t fall regularly.” That got her thinking. Was there a way to grab those rare raindrops and store them in the soil? That way, the water could be released slowly over time. Crops could use it even during the driest times.

Kiara’s curiosity led her to research superabsorbent polymers. The powder form of these chemicals can absorb hundreds of times their own weight in liquid. They do so by forming chemical bonds with water molecules.

A super-absorbent polymer, or SAP, spread in soil could theoretically absorb and hold rainwater for plants to use during periods of drought. Unfortunately, most SAPs are expensive and made with chemicals that are toxic to plants and animals. Kiara needed something that was cheap and safe to use. “It turns out you can find these kinds of molecules in a lot of natural sources,” she says. “The most abundant option was something that I found in orange peel.”

Orange peels contain pectin, a gelling agent often used to make jam. The peels also contain polysaccharides, a type of sugar molecule found in many SAPs. Kiara hypothesized that she could use these substances as the basis for a cheap and effective SAP. And it would also be biodegradable, or able to naturally break down without harming the environment.

Kiara’s question led her to research super-absorbent polymers, or SAPs. These chemicals can take the form of a powder. Then they can soak up hundreds of times their own weight in liquid. How? They form chemical bonds with water molecules.

An SAP could be spread in soil. Then it could soak up and hold rainwater for plants to use during a drought. At least that’s the idea. But most SAPs are expensive. They’re also made with chemicals that are harmful to plants and animals. Kiara needed something that was cheap and safe to use. “It turns out you can find these kinds of molecules in a lot of natural sources,” she says. “The most abundant option was something that I found in orange peel.”

Orange peels contain pectin. This gelling substance is often used to make jam. The peels also contain polysaccharides. This type of sugar molecule is found in many SAPs. Kiara thought she could use these substances to make a cheap and effective SAP. It would also be biodegradable. That means it would naturally break down without harming the environment.

Kiara made three orange-peel-based mixtures and tested their absorbing power against that of three common SAPs. She performed three experiments. The first tested water absorption. The second examined the ability of the substances to maintain soil moisture over a three-week period. And the last looked at how well the materials helped an actual plant survive in drought conditions.

A homemade mixture of orange peel, avocado skin, and lemon juice came out on top. It beat Kiara’s other mixtures, as well as commonly used commercial SAPs (see Put to the Test).

Kiara made three mixtures based on orange peel. She tested them against three common SAPs. She did three experiments. The first tested how much water they soaked up. The second ran over a three-week period. It tested how moist they kept the soil. And the last used a real plant in drought conditions. This test looked at how well the materials helped the plant survive.

Which substance came out on top? One of Kiara’s homemade mixtures. It contained orange peel, avocado skin, and lemon juice. It worked better than her other mixtures. It also beat commonly used (see Put to the Test).

“It’s a very impressive result,” says Vincent Remcho, a materials science professor at Oregon State University. He previously worked with a company developing its own biodegradable SAP for agricultural use. That company used lignin, a molecule found in the supporting tissues of plants. It is also a by-product left over from making paper and wood pulp

“Her choice of the orange peel was spot-on,” says Remcho. “So many industries have by-products that they’d love to use for something else. She really thought this through.”

“It’s a very impressive result,” says Vincent Remcho. He’s a materials science professor at Oregon State University. He used to work with a company that was making its own SAP. The material was for crop use and was biodegradable. That company used lignin. This molecule is found in the supporting tissues of plants. It’s left over when paper and wood pulp are made.

“Her choice of the orange peel was spot-on,” says Remcho. “So many industries have by-products that they’d love to use for something else. She really thought this through.”

Remcho isn’t the only one impressed with Kiara’s results. Last year, Kiara submitted her project to the Google Science Fair, a global science competition for kids ages 13 to 18. She was invited to present her findings at Google’s headquarters in Mountain View, California, along with other teenage scientists from around the world. The contest’s judges awarded Kiara’s project the grand prize, which included a $50,000 scholarship. She hopes to use that money to attend college in the U.S. next year.

Kiara’s achievements may be extraordinary, but she says that anyone can do what she’s done. All you need to do is believe in yourself, stay curious, and keep experimenting. “It’s never too early to start doing science,” says Kiara. “Even if you’re young, you still have the ability to create something world-changing.”

Remcho is impressed with Kiara’s results. He isn’t the only one. Last year, Kiara sent her project to the Google Science Fair. This science competition is for kids ages 13 to 18. She was invited to present her findings at Google’s headquarters in Mountain View, California. So were other teenage scientists from around the world. The contest’s judges gave Kiara’s project the grand prize. It included a $50,000 scholarship. She hopes to use that money to attend college in the U.S. next year.

Kiara’s successes may be amazing. But she says that anyone can do what she’s done. You just need to believe in yourself, stay curious, and keep experimenting. “It’s never too early to start doing science,” says Kiara. “Even if you’re young, you still have the ability to create something world-changing.”