By Soil CRC Soil Knowledge Broker Felicity Harrop

Considering the dry situation many landholders in southern Australia are currently experiencing, it is timely to share the Soil CRC resources for farmers, advisors and researchers on soil management during and after drought. 

Australia’s variable climate presents ongoing challenges for land managers, particularly during and after drought. The Soil has produced a suite of practical, science-based resources to help farmers, graziers, and landholders manage soil health through these tough conditions. 

At the heart of these resources is a focus on protecting and restoring soil function, whether in cropping or grazing systems. The fact sheets and guides available on the Soil CRC website offer actionable strategies for: 

  • Minimising erosion and soil degradation during drought
  • Rebuilding soil structure and fertility after drought
  • Building long-term resilience to future dry periods. 

During drought – protect your soil

Protecting soil is the main aim – it is the source of nutrients, water, and organic matter, which is important for optimum productivity and climate resilience. Avoiding soil movement is the first line of defence. Protect the most productive paddocks by maintaining stubble, removing livestock early, using containment areas for stock feeding and regaining cover using quick growing species established with minimum soil disturbance. 

Recovery preparation – test your soil

“Don’t guess, test!” Soil changes during drought vary due to soil type, changes in microbial activity, soil movement and reduced plant growth. Soil testing across different soil types is the first step in recovery planning and correcting soil limitations.

Understand nutrient availability for optimum fertiliser budgeting and soil amelioration requirements. For example, use lime to increase soil pH and gypsum to improve water infiltration, to maximise plant growth when it rains.  

On sandy soils, consider tackling water repellence with wetting agents or clay spreading. Water repellency is usually a bigger issue in sands because the hydrophobic molecules are more able to dominate the surface areas of the sand’s minerals, compared to the large surface area of clay particles. 

Herbicide carryover is a risk, as rainfall and soil type are key drivers of herbicide breakdown in soil. Review herbicide guidelines and labels. Commercial residue soil testing is available. A Soil CRC project led by Dr Mick Rose from Southern Cross University provides more information in this area (see our research findings fact sheet).

Plant fast growing crops and pasture with minimal soil disturbance to quickly stabilise and cover soil. Consider multiple species for future ground cover management and managed grazing to promote recovery and cover.

The Soil CRC’s ‘Plant-based solutions to improve soil performance’ fact sheet states, “increased plant diversity in cropping systems typically increases soil microbial diversity, which in turn may be linked to improved soil function and farming system resilience.”   

Building long-term soil resilience

Resilience denotes the capacity of soil to recover its functional and structural integrity after experiencing stress. Soil CRC researcher Dr Rezaei Rashti from Griffith University suggests, “The abundance of organic matter and nutrients in the soil greatly influences microbial activity and resilience, with richer soils generally supporting more robust microbial communities capable of better surviving drought conditions.” 

Soils that are more resilient to drought have a greater capacity to capture and store moisture, enabling crop roots to penetrate deeper and increasing biological activity and nutrient supply to plants. This leads to increased biomass production above and below ground, which in turn will provide more surface cover and increased yields. 

Droughts can highlight unknown soil constraints. The ‘Managing soil for high performance after a drought’ project (4.3.003) highlighted that drought is an opportunity to undertake soil amelioration on-farm, with one project participant stating, “There is an ability to start to manage within a drought for after a drought. If you know what your constraints are, remove them.”   

Addressing soil constraints and limitations to plant growth will ensure greater plant biomass above and below ground providing more organic material to stimulate microbial activity, thereby accelerating nutrient cycling. Invest in addressing constraints such as soil acidity, sodicity and compaction to improve soil resilience and increase organic matter for nutrient cycling and water infiltration.  

Consider subsoil manuring or modification as per deep soil testing results. The Soil CRC research ‘Addressing complex soil constraints’, challenges the assumption that problem soils are inherently unproductive. In many cases, poor crop performance is due to soil limitations that can be overcome with amendment addition. Traditional topsoil testing and surface amendment strategies often miss deeper constraints, limiting the effectiveness of soil management. 

In addition, understanding how healthy soil works and how it stands up to tough weather is key to keeping farms productive for the long haul. It is also important to know what might make it hard to use certain soil-building practices.

The Soil CRC’s guides are grounded in the latest research and tailored to the diverse soil types and farming systems across Australia. Whether you are looking to improve ground cover, manage nutrient cycling, or address subsoil constraints, Soil CRC’s drought management resources are a valuable starting point. 

Further information and resources