A 16-year-old South African student has won the grand prize at Google’s Science Fair for her simple orange peel mixture that could help farmers across her drought-stricken country.

Kiara Nirghin of Johannesburg won Google Science Fair’s US$50,000 grand prize Tuesday for her submission “Fighting Drought with Fruit.” She was one of 16 finalists who were invited to the ceremony at Google Headquarters in Mountain View, Calif.

Nirghin’s innovation combines sundried orange and avocado peels to create a biodegradable mixture that can retain more than 75 per cent of rainwater.

“I believe that food and chemistry are undoubtedly linked in the intertwined science web. I love molecular gastronomy and the application of scientific principles in food creation,” Nirghin wrote in her submission.

The innovation came in response to one of South Africa’s most devastating droughts in 45 years. In all of 2015, regions across the country received only 403 mm of rain on average, 34 per cent below the annual average, according to the South African Weather Service.

As farmers’ crops withered and died, many turned to superabsorbent polymers (SAPs) to retain water in soil. The powders hold large amounts of water relative to their mass and create a hydrogel “reservoir.” However, SAPS are also very expensive and not biodegradable.

Nirghin wanted to find a natural solution that farmers could afford. She discovered orange peels could work as a biodegradable polymer but would still need to be chemically processed. Instead, she boiled the orange peels with oil from avocado peels then used the photo polymerization of sunlight to connect the polymers.

Over the course of 45 days, Nirghin watched as pots containing her mixture retained more water, kept soil moist and produced more flowers than those with commercial SAPs. Products on the market can cost up to $3,000 per metric ton, while she said her version would cost $30-60 per metric ton.

Nirghin said the Google Science Fair prize would help bring her idea to life.

“With the prize I will hope to continue my studies in science, but also further the scientific development and application of my idea, and in addition extend scientific progress in elevating the problems that South Africa faces in food security and sustainable agricultural development,” she wrote in her submission.