Wax-coated sand promises to increase crop yields, slow soil evaporation in desert regionsMarie Donlon | May 13, 2022
Scientists from Saudi Arabia’s King Abdullah University of Science & Technology (KAUST) have developed a biodegradable ground covering featuring wax-coated sand for keeping soil wet in desert regions with limited freshwater resources.
To better control soil evaporation in desert regions, which is often brought about by high temperatures and dry winds that accelerate soil evaporation and increase transpiration from plants, the KAUST team coated a superhydrophobic sand dubbed SandX in a wax coating.
To create the wax-coated sand, the KAUST team dissolved paraffin wax in hexane and added SandX to the mixture. As the mixture dissolved, it left behind a 20 nm thick wax coating on the grains of sand.
The wax-coated sand grains were then applied in a 5 mm to 10 mm thick layer like mulch to an open field in Saudi Arabia where the material reportedly decreased the loss of soil moisture by 50% to 80%. Likewise, tomato, barley and wheat plants trialed with a mix of the wax-coated sand and mulch reportedly, over time, yielded more fruits and grains than those using traditional mulch.
The researchers suggest that the mixture could benefit agriculture in arid regions like Saudi Arabia where an estimated 70% of that country’s freshwater resources are already being used for agriculture but where groundwater aquifers that supply 90% of irrigation water are subsequently being depleted.
The article, Effects of superhydrophobic sand mulching on evapotranspiration and phenotypic responses in tomato (Solanum lycopersicum) plants under normal and reduced irrigation, appears in the journal Plant-Environment Interactions.