Authors: Melissa Fraser1, Nigel Wilhelm2, David Davenport1
Research Team: Peter Telfer2, Brett Masters1, Claire Dennerley1
1PIRSA Rural Solutions SA, 2South Australian Research & Development Institute
Funded By: GRDC Sandy Soils CSP00203
Project Title: Increasing production on sandy soils in low and medium rainfall areas of the Southern Region
Peer Review: Lynne Macdonald
Key Words: low rainfall, clay spreading, drought
- April to October rainfall (113mm) at Karoonda was the second lowest on record in 2018; crop production suffered as a result.
- Incorporation of clay (spading, 30cm) improved establishment compared to the control and the spaded alone treatments (Fig. 1).
- Crop roots accessed deeper water (60cm) in August under the intensive amelioration treatment compared to September under the control. This treatment (Spaded clay+Luc+nut) also had the highest flowering biomass (Fig. 1).
- Depleting soil moisture reserves in winter, combined with limited spring rainfall, led to plant death on clayed plots and grain yields collapsed as a result (Fig 1). No treatment significantly outperformed the control in grain yield.
- The fodder value of additional biomass needs to be considered in such years, along with the soil protection benefits associated with heavier stubbles.
- Changes in soil chemical, hydrological and physical characteristics as a result of spading and lucerne and clay addition will be the focus of 2019 soil measurements at the site.