Researchers at the University of Nevada are testing oil-coated sand as an alternative to plastic mulch to help minimize water loss in fields. In laboratory experiments, soil treated with a thin layer of soybean oil-coated sand had up to 96% lower evaporative water loss compared to bare soil. The plastic mulch commonly used in agriculture can degrade soil and water quality. Bio-based soil coatings - such as soybean oil - could be low-impact alternatives to plastic mulch while performing at similar levels for water retention. To coat the sand, researchers mixed sand and oil, heated the mixture, and then washed and dried it. This process chemically modifies the oil, partially polymerizing it, which causes it to form a coating around individual sand particles. Rain water can filter down through the sand to the soil below, but evaporation is significantly inhibited.
Has anyone out there experimented with this? Is it effective? Could it be sustainable to use in developing countries using native oils?