In search of the green, green grass of home

The Science of Surfaces is a four-part weekly series that looks at the surfaces we walk on so often but know so little about. In the first part, The Straits Times looks at the types of grasses being used in Singapore
Grace Chua, Straits Times 2 Jan 10;

TALK about natural heritage.

The lawns of the Istana, Asian Civilisations Museum, HortPark and Fort Canning Park are carpeted with the last remnants of one of the few native species of grasses here.

Zoysia matrella, or Manila grass, is a fine-leaved, hardy grass resistant to trampling and lack of sunlight.

But it is used in less than 10 per cent of public green spaces here because it is pricey.

Most of the island's public spaces are covered with cow grass, a coarser South American native species and a leftover from British colonial times.

Cow grass, or Axonopus compressus, does not need as much watering and tending as other grasses, but it tends to develop bald patches under heavy foot traffic and waterlogged, muddy conditions.

Sport fields are either turfed with cow grass - which costs about $25,000 for a standard-sized football field - or synthetic turf at a cost of about $500,000, said the Singapore Sports Council. The upcoming Sports Hub, for instance, will use cow grass.

That type is the cheapest at $4 to $6 per sq m, compared with $8 to $12 for Zoysia varieties, said Mr Veera Sekaran of landscaping company Greenology.

But, he added, the price does not factor in concerns such as proper drainage and whether it will thrive in shady conditions.

The National Parks Board (NParks) is studying a dozen types of grasses in order to see if the country should re-patch some areas with better grass.

The grass samples will be put through different conditions such as various soil fertility levels, soil types, shade and trampling conditions.

These grasses being tested include Manila grass and cow grass, but also Bermuda grass and seashore paspalum, among others.

Bermuda grass and seashore paspalum are frequently used on golf courses for their lush, high-density appearance, but need more watering and mowing than the other species.

NParks will reach a decision after a year-long study, which will be completed near the end of this year.

Twelve types of grasses may seem like a lot to test out, but there are several hundred species of grasses that can be used for turfing lawns, said American expert Milt Engelke of Texas A&M University, who was in town for an international turf grass seminar recently.

In the United States, temperate grasses such as Kentucky bluegrass are popular in the northern latitudes, while more tropical species such as Bermuda grass are popular in warm states like Florida.

Grass also serve important environmental and economic functions, Dr Engelke said.

They can be so hardy, he said, that 'if you denude the earth and walk away, the first thing that will be back is grass'.

A single square metre of grass produces enough oxygen for one person for a day, and sequesters carbon dioxide.

And grass root systems can be up to 30cm deep in healthy soil, holding the soil together and preventing erosion.

Grass lowers surface temperatures as well, and is used in green rooftops and green walls to help keep buildings from overheating.

And some turf grasses can tolerate and accumulate high levels of chemical and organic pollutants in a soil-cleaning process called phytoremediation.

For example, Bermuda grass can absorb hydrocarbons, while some fescues (a tufted, cool-climate grass) can take up radioactive isotopes.

Singapore begins first turf research programme to find durable grass types
Seet Sok Hwee/Evelyn Choo, Channel NewsAsia 2 Jan 10;

SINGAPORE: The National Parks Board (NParks) has spent a S$100,000 to pilot Singapore's first turf research programme. This is to understand what types of grass are most suitable for the country.

The turf you see in most parts of Singapore is cowgrass which has been found to be weak against Singapore's high rainfall and hot climate.

And NParks hopes to replace the current cultivation with more durable grass types, like turfgrass.

It is known to reduce ambient temperatures and controls soil erosion.

So a one-year study of 12 grass species has been launched and the research facility is located at HortPark.

Dr Tan Puay Yok, deputy director, Centre for Urban Greenery and Ecology, NParks, said: “One of the objectives of this research facility is of course to find a suitable combination of soil and grass that does not require that high a level of maintenance.

“So for instance, if we can find a grass that is slower-growing but very well-adapted to water issues, lack of sunlight issues then we can potentially cut down the frequency of cutting. That in itself has an economic impact on maintenance cost of green estates. - CNA/vm