Dry spell? Get soil to release water to plants

Left: (From far left) Dr Goh Chin Foo, deputy director of NTU's School of Materials Science and Engineering, Prof Lam and Prof Chen were among the scientists who worked with NParks to develop the formula that can help plants better absorb and retain
(From far left) Dr Goh Chin Foo, deputy director of NTU's School of Materials Science and Engineering, Prof Lam and Prof Chen were among the scientists who worked with NParks to develop the formula that can help plants better absorb and retain water. ST PHOTOS: ONG WEE JIN
Left: (From far left) Dr Goh Chin Foo, deputy director of NTU's School of Materials Science and Engineering, Prof Lam and Prof Chen were among the scientists who worked with NParks to develop the formula that can help plants better absorb and retain
The control balsam plant on normal soil (left), next to another balsam plant using soil with the new formula.ST PHOTOS: ONG WEE JIN

NTU and NParks develop substance that, when sprayed on soil, will release water molecules during scarce rainfall

What if there's a way for the soil itself to release water to help plants during prolonged periods of drought?

A new water-saving substance may just be the answer.

Gardeners spray a solution on the soil and when rainfall is scarce, a substance in the solution releases water molecules back into the soil.

The substance was developed by a team of scientists from the Nanyang Technological University (NTU) in conjunction with the National Parks Board (NParks), which manages over 300 parks here.

NParks said it will be using the special substance to help plants better absorb water with climate patterns changing and longer periods of intense drought.

"Developing a water retention formula will enable better utilisation of scarce water resources, especially during periods of drought," said Dr Genevieve Ow, senior researcher at the NParks' Centre for Urban Greenery and Ecology.

During the dry spell from Jan 13 to Feb 8, 2014, for instance, rain was absent for 27 consecutive days. That caused symptoms of water stress such as browning and shedding of leaves in grass, trees and shrubs, she said.

The formula will be applied after putting it through the required tests, which will "provide a better gauge of water saved, and monitor the progress to improve our water conservation efforts", said Dr Ow.

In the event of a prolonged dry spell or a national water crisis, only young saplings and heritage trees are watered, sparingly. Non-potable water is used but the agency hopes that the formula will help to save even more of the precious resource.

As dead plant matter accumulates on soil surfaces, it makes it harder for water to be absorbed efficiently and water molecules could simply run off the surface of slopes leading to water wastage as a result, said Associate Professor Lam Yeng Ming from NTU's School of Materials Science and Engineering.

"What's exciting about this technology is that it helps water to be absorbed into the soil with little or no surface run-off," said Prof Lam.

"On top of this, the design of the materials used in the formulation is such that excess water can be retained and then subsequently released when the soil becomes dry."

Prof Lam said the substance has since been tested and found to be environmentally safe and can be used on a variety of horticulture plants.

Currently undergoing its final stage of testing, the technology could be ready as soon as the first quarter of next year.

So far, it has been tested on 50,000 plants across 15 to 20 plant species - including the ixora, ipomoea and hibiscus from NParks - at the greenhouse at the National Institute of Education, said Assistant Professor Chen Zhong from NIE's natural sciences and science education department.

Those grown in the treated soil were shown to use at least 50 per cent less water compared to those without. Because of its ability to retain water, plants that had their soil treated also looked healthier.

Prof Lam said that the team has plans to commercialise the technology and hopes that it can one day be used in agriculture.

"The agriculture industry has been hard hit by global warming which has decimated many crops' yield over the past years," she added.

A version of this article appeared in the print edition of The Straits Times on November 04, 2016, with the headline 'Dry spell? Get soil to release water to plants'. Print Edition | Subscribe