Innovative Management Solutions To Enhance Crop Productivity in Heavy Soils in The Southern Region

In the context of Australian agriculture, heavy soils are generally characterised by a predominance of clay content (exceeding 10%) within their profiles and are recognised for their management challenges. This category encompasses soil types such as Sodosols, Vertosols, Calcarosols, Chromosols, and Dermosols.

Over recent years, targeted research and extension have led to productivity gains and helped sandy soil growers address issues such as acidity, water repellence, and infertility, leading to practical management strategies and widespread on-farm adoption. However, the Southern Region’s heavy soils have not seen the same level of Research Development & Extension (RD&E) investments, resulting in a stagnating productivity of these soils due to persistent physical and chemical constraints like poor structure, low infiltration, hard-setting, and frequent waterlogging. These soils demand different solutions than their sandy counterparts.

Previous research in the High Rainfall Zone (HRZ, such as DJP2209-002RTX) has identified profitable subsoil amelioration strategies—such as deep incorporation of organic amendments and gypsum—that can deliver impressive yield increases. However, the high cost (often greater than $1000/ha) and logistical complexity of such treatments have limited their adoption, especially in the Medium and Low Rainfall Zones (MRZ and LRZ), where economic returns are uncertain and payback periods are highly variable. Furthermore, only a minority of surveyed growers reported positive impacts from common amendments like gypsum, underscoring the need for more tailored, effective solutions.

GRDC is seeking a lead organisation to build on prior GRDC soil initiatives to deliver a coordinated Research, Development & Extension program to address constraints to profitability of heavy soils using a zonal approach for the different climatic conditions.

1) In the HRZ, it seeks to refine and expand the adoption of proven subsoil treatments through large-scale, monitored demonstration trials and barrier-specific extension activities.

2) In the MRZ and LRZ, the focus is on pioneering topsoil amelioration methods, such as surface-applied amendments and shallow reengineering techniques, to address surface sealing and hard-setting more cost-effectively.

Effective data sharing and integration are essential for utilising previous research and tools, supporting informed strategies and efficient knowledge transfer in all rainfall zones.

Building on prior GRDC soil projects (e.g., DJP2209-002RTX), this program encourages multidisciplinary collaboration, integrates local reference groups, and features a strong extension component for grower adoption. Applicants must show they can coordinate across rainfall zones, manage complex trials, and work with existing GRDC soil initiatives and industry partners.