Farmers and advisors attending BCG’s Main Field Day on Wednesday 10 September at Birchip will have the chance to step into a 20-metre-long soil pit to see first-hand what lies beneath their crops and how it impacts production.
BCG Senior Scientist Dr James Nuttall will lead the discussion, drawing on his extensive research into subsoil constraints, water movement and crop responses in Mallee farming systems.
Soils across the Wimmera and Mallee are typically alkaline, with subsoils often containing chemical and physical barriers such as salinity, boron, sodicity and compaction. These features can limit soil water movement and how far crop roots penetrate, reducing their ability to chase water deeper in the profile. As a result, growers are considering management practices such as deep ripping to address compaction and improve root access to moisture, though this can carry risks in alkaline soils where subsoil constraints may be brought closer to the root zone. The result can be water sitting unused below the root zone – while crops above may be under stress.
“Wheat, barley, canola and pulses all have different rooting depths and tolerances to subsoil constraints,” Dr Nuttall explained. “If roots can’t access water and nutrients due to chemical toxicity or physical barriers, yield potential is lost – even if the water is there.”
At the Birchip soil pit, Dr Nuttall will walk growers through the typical characteristics of alkaline soils in the region, explain how subsoil properties affect the movement and storage of water, and show what soil water is currently available in the pit and what crops are using. He will also explore whether management of subsoil constraints can improve root growth and crop access to water, and highlight how building well-structured soils can boost resilience and sustain production in dry seasons.
“Every millimetre of crop water use is valuable in our environment,” Dr Nuttall said. “Understanding how soil and roots interact is an important step in managing for efficient use of water in the system and improving the resilience of our cropping systems.”
The soil pit session will be one of the highlights of a full program at BCG’s Main Field Day, bringing together growers, researchers, and advisors to share the latest knowledge and strategies to drive farm productivity and profitability. Entry is free for BCG members and $50 for non-members. To secure your ticket or to become a BCG member please visit the BCG website bcg.org.au.
The soil pit at BCG’s Main Field Day is supported by the Australian Government through funding from the Natural Heritage Trust under the Climate-Smart Agriculture Program.
Photo: BCG 2003
