Wax-coated sand keeps soil wet longer, improves crop yields in arid
regions

Date:
March 16, 2022
Source:
American Chemical Society
Summary:
Dry, hot regions are difficult places to grow plants because the
soil dries out quickly. As a result, farmers in arid and semi-arid
regions irrigate their fields with buried networks of irrigation
tubing and cover the ground with plastic sheets. But plastic sheets
are expensive and create waste. Now, researchers have developed
a simple, biodegradable ground cover -- wax-coated sand -- which
keeps soil wet and increases crop yields.



FULL STORY ==========================================================================
Dry, hot regions are difficult places to grow plants because the soil
dries out quickly. As a result, farmers in arid and semi-arid regions
irrigate their fields with buried networks of irrigation tubing and cover
the ground with plastic sheets. But plastic sheets are expensive and
create waste. Now, researchers reporting in ACS Agricultural Science
& Technology have developed a simple, biodegradable ground cover --
wax-coated sand -- which keeps soil wet and increases crop yields.


==========================================================================
To irrigate crops, farmers usually get water from nearby waterways
or underground aquifers. These supplies can be rapidly depleted when
growing plants in arid regions, where the soil is comprised mostly of
sand and can't hold onto water well. One way to improve irrigated water's efficiency is to make sure it stays in the soil long enough so that
plants' roots can take it up. Previous studies have shown that ground
cover barriers, such as plastic sheets and engineered nanomaterials,
can slow evaporation and enhance plant growth and crop yields. However,
both could leach unwanted compounds into the soil with unknown long-term impacts. Some plants and animals naturally produce waxy substances that
trap and pool water from fog or condensation so that they can access
these moisture sources. Taking inspiration from nature, Himanshu Mishra
and colleagues wanted to see if they could coat sand with wax, creating
an environmentally benign ground cover to control soil evaporation.

The researchers chose purified paraffin wax, a biodegradable substance available in large quantities, for their experiments. They dissolved
the wax in hexane and poured silica sand into the mixture. As the
solvent evaporated, a 20-nm-thick coating of wax was left behind on the
grains. When the team applied the wax-coated sand in a thin layer on an
open field in Saudi Arabia, it decreased the loss of soil moisture up
to 50-80%. Field trials revealed that tomato, barley and wheat plants
mulched with the new material produced substantially more fruit and grain
than those grown in uncovered soil. In addition, the microbial community
around the plants' roots and in the soil wasn't negatively impacted by
the waxy mulch, which could have acted as a food source for some of the microbes. This simple nature-inspired technology could make water use
more efficient in arid regions, the researchers say.


========================================================================== Story Source: Materials provided by American_Chemical_Society. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Adair Gallo, Kennedy Odokonyero, Magdi A. A. Mousa, Joel Reihmer,
Samir
Al-Mashharawi, Ramona Marasco, Edelberto Manalastas, Mitchell J. L.

Morton, Daniele Daffonchio, Matthew F. McCabe, Mark Tester,
Himanshu Mishra. Nature-Inspired Superhydrophobic Sand Mulches
Increase Agricultural Productivity and Water-Use Efficiency in
Arid Regions. ACS Agricultural Science & Technology, 2022; DOI:
10.1021/ acsagscitech.1c00148 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220316115006.htm

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