Superhydrophobic sand mulches increase agricultural productivity in arid regions

TL;DR

This study introduces superhydrophobic sand (SHS) as an effective, biodegradable mulch that significantly reduces evaporation and boosts crop yields in arid regions, even under saline water conditions.

Contribution

The paper presents a novel bio-inspired superhydrophobic sand mulch that enhances water retention and crop productivity in arid agriculture, outperforming traditional plastic mulches.

Findings

SHS mulch reduces soil evaporation dramatically.

Crop yields increased by 17%-73% with SHS application.

SHS improves yields under saline water irrigation, up to 208%.

Abstract

Excessive evaporative loss of water from the topsoil in arid-land agriculture is compensated via irrigation, which exploits massive freshwater resources. The cumulative effects of decades of unsustainable freshwater consumption in many arid regions are now threatening food-water security. While plastic mulches can reduce evaporation from the topsoil, their cost and non-biodegradability limit their utility. In response, we report on superhydrophobic sand (SHS), a bio-inspired enhancement of common sand with a nanoscale wax coating. When SHS was applied as a 5 mm-thick mulch over the soil, evaporation dramatically reduced and crop yields increased. Multi-year field trials of SHS application with tomato (Solanum lycopersicum), barley (Hordeum vulgare), and wheat (Triticum aestivum) under normal irrigation enhanced yields by 17%-73%. Under brackish water irrigation (5500 ppm NaCl), SHS mulching produced 53%-208% higher fruit yield and grain gains for tomato and barley. Thus, SHS could benefit agriculture and city-greening in arid regions.