Sean Murphy conducts measurements at the trial site. He says successful adoption of subtropical grasses in the Goonoo Goonoo Creek area and wider North-West Slopes is likely to make good use of summer rainfall, while reducing deep drainage losses and saline inflows to the Namoi River.

Subtropical grasses could one day hold the key to natural resource management in the Namoi Catchment.

These grasses maximise use of summer rain, reduce surface run off and protect soil from erosion.

But it’s not just a win for the environment, since the grasses offer livestock producers the ability to produce large amounts of pasture dry matter (8000 to 14 000 kilograms dry matter per hectare each year).

Successful adoption of subtropical grasses now rests with a team of NSW Department of Primary Industries researchers at the Tamworth Agricultural Institute working in conjunction with the Co-operative Research Centre for plant-based management of dryland salinity.

They aim to improve subtropical grass establishment and assess their potential as a forage source, as well as their role in mediating deep drainage.

Field experiments sown in December last year will test the dry matter production and soil water use by a range of subtropical grass species in the Goonoo Goonoo Creek area near Tamworth, targeted by the Namoi Catchment Management Authority as a high priority sub-catchment for salinity.

Katambora Rhodes Grass, Premier Digit, Swann Forest Bluegrass, and Bambatsi Panic were chosen, after being identified in plant evaluation studies as having high potential as productive and persistent pasture species in the summer rainfall environment.

NSW DPI researcher, Sean Murphy, said studies would focus on the hydrological impact of these species compared with native grass pasture, annual forage crops, lucerne and saltbush stands.

"Matching pasture dry matter production to rainfall patterns and management and moderation of stream salinity and salt load exported by river systems are priority issues for natural resource management in the Namoi River catchment," Dr Murphy said.

"As part of the research we will measure the depth of soil water extraction by plant roots and so the ability of these grasses to reduce deep drainage, while recording their water use efficiency for dry matter production.

"Surface run-off and soil loss by erosion and the performance of the grasses to control these will also be assessed at the site." Dr Murphy said salt was now exported from Goonoo Goonoo Creek at a rate estimated to be around 18 tonnes per square kilometre per year and he anticipated that planting subtropical grasses would prevent an increase in the salt load for the catchment.

"However, because of generally poor establishment of subtropical grasses and perceived problems in matching their seasonal growth and quality characteristics to livestock production systems, these species are not widely sown by producers," he said.

"Agronomy studies at the research site will focus on improving establishment and the role of nitrogen in raising forage quality to meet specific livestock enterprise requirements."

Contact Sean Murphy, Tamworth, (02) 6763 1244, sean.murphy@dpi.nsw.gov.au.