Trials have been planted as part of a new research project to improve the productivity and profitability of soils with sodicity and transient salinity in low rainfall areas of the eastern grainbelt in Western Australia.
Growers across an estimated area of 2.5 million hectares are missing out on increased yields of 0.5-1.5 tonnes per hectare, due to the interaction between sodicity and transient salinity, often associated with high subsoil alkalinity and poor soil structure.
The $4.8 million project, with co-investment from Department of Primary Industries and Regional Development and the Grains Research and Development Corporation, will explore management options and treatments to increase water availability to the root zone.
Five trials using wheat and barley indicator crops have been planted at Merredin, Beacon and Lake Grace in 2019 to evaluate a combination of mitigation and amelioration strategies to determine the most profitable benefits.
A further three glasshouse trials will look at the effects of amendments on soil chemical, physical and biological properties.
Project leader David Hall said the research would build on previous work by department scientists to explore water harvesting techniques and furrow root zone amelioration treatments on sodic soils.
“Our team has been assessing options, such as water harvesting though furrow formation and the use of strategically placed water repellent compounds on the ridges, combined with in-furrow surfactants, soil loosening and soil amendments,” Mr Hall said.
“The project will also assess the novel use of commercially available polymers and wetting agents, as well as water harvesting from semi-permanent ridges, while also looking at strategies to improve water infiltration, storage and root access in semi-permanent seeding furrows.
“While each component will be assessed individually, we expect a combination of mitigation and amelioration approaches may be required to provide the largest and most profitable benefits.”
Mr Hall said data generated from the trials will be incorporated with crop simulation models to generate preliminary long-term data sets and determine the profitability and reliability of these treatments.
“The depth of knowledge and research on sodicity and transient salinity in WA has been limited to date,” he said.
“This project also includes national and international study tours to develop contacts and learn how other farmers and experts are addressing sodicity and transient salinity so we can successfully manage these soil constraints.
“Department research suggests the estimated impact of sodicity and transient salinity on lost crop production is at least $130 million per year.
Mr Hall said the research aimed to ultimately reduce the production risk of these soils and improve their profitability.
“By developing better management strategies to overcome these soil constraints, growers will be able to close the yield gap in low to medium rainfall years and retain affected paddocks as part of their cropping programs,” he said.
The four year project will conclude in 2022, with the development of an agronomic package.
This article was first published in R4A.