"Agriculture is the biggest consumer of water in the world; especially here in arid regions where agriculture isn't possible without irrigation," said KAUST student Adair Gallo Junior. With an estimate of merely 2.5% of the globe's water supply being fresh water, and only 1% readily accessible, it's evident that effective water management is essential to feed a growing world population estimated to be at 9 billion people by the year 2050. "So if it's possible to save a little bit of water, or generate higher yields with the same amount of water, in the end it's a win," Gallo added.

The graduating Water Desalination and Reuse Center masters student, who will also be completing his Ph.D. at KAUST, recently won the best poster award at the 5th Water Arabia Conference and Exhibition held at Al-Khobar, Saudi Arabia on October 17-19, 2017. Gallo's poster entitled "Superhydrophobic Sand Mulches for Desert Agriculture" detailed a novel and patent-pending technique that uses superhydrophobic sands for reducing the evaporation of water from soils.

In the works for the past year and a half, the innovative methodology consists of coating sand or soils with a cheap and abundantly available paraffin wax –- a byproduct of oil. The paraffin wax coating essentially prevents water from either infiltrating the sand when poured onto it, or to easily evaporate from the soil.

When a 1-centimeter coating layer of the superhydrophobic sand is deposited on top of the soil, it immediately reduces the evaporation rate of the water from the soil. It basically keeps water inside the soil for a longer period of time -- leaving more water available for the plants to grow. This has particularly significant implications for agriculture in arid regions of the world.

In order to make this technique feasible, an irrigation line is placed under the sand layer. Gallo and colleagues tested the innovative methodology inside the greenhouse at KAUST and it yielded promising preliminary results. They completed filed-scale experiments at King Abdul Aziz University's farming and agriculture facilities.

"We got some really exciting results. It was our first round of few trials and for tomatoes it was a 100% increase in the biomass and for barley it was around 140% increase in the grains. So it was really good and exciting results and we're still working on this concept," said Gallo.

They are now preparing a new crop season where the team will test other crops, apart from tomatoes and barley. Different irrigation regimes will also be tested.

"Any technology that can reduce the irrigation needs for agriculture is very welcome," said Gallo.

WDRC was represented at the Water Arabia Conference by Ph.D. students Adair Gallo, Sandra Medina and Jamilya Nauruzbayeva.

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