Soil and Carbon

Exploring Soil Carbon in the Mallee

Soil carbon is a hot topic in agriculture, but what does it really mean for farmers in low-rainfall areas like the Mallee?

See more at MSF

  • Understand the Challenges of Low Soil Organic Carbon

    Mallee soils naturally have low levels of soil organic carbon (SOC), often less than 1%. This is due to two key factors: low rainfall limits plant growth, which reduces carbon inputs, and the sandy nature of the soils means less clay is available to protect organic matter, leading to faster carbon breakdown. Despite these challenges, SOC plays a vital role in soil health by improving nutrient cycling, water retention, and overall soil structure.

  • Protect What You Have: Minimise Carbon Loss

    The first and most practical step for Mallee farmers is to focus on minimising carbon loss. Wind erosion, a common issue in the region, strips away valuable organic matter. Practices like maintaining ground cover, using no-till seeding techniques, and avoiding overgrazing can significantly reduce erosion and preserve existing soil carbon. These simple but effective measures ensure that carbon already in the soil is not lost.

  • Maximise Biomass to Build Carbon Inputs

    ncreasing biomass production is both profitable and beneficial for soil carbon levels. Boosting crop and pasture growth through optimised nutrition, deep ripping, and clay incorporation helps supply organic matter to the soil. While most of the added biomass in sandy soils breaks down quickly, it still supports nutrient cycling and enhances soil health. These practices not only improve carbon inputs but also set the stage for higher yields and more resilient soils.

Project Overview

Soil Carbon in the Mallee: Insights from Experts

Soil carbon is a hot topic in agriculture, but what does it really mean for farmers in low-rainfall areas like the Mallee? Our recent webinar, hosted by Mallee Sustainable Farming and the Soil CRC, took a close look at what soil carbon looks like in our Mallee region, and what goals we should have in managing it.

Our expert panel featured insights from Dr. Karl Anderson of NSW Department of Primary Industries, and Dr. Amanda Schapel from SA Department of Primary Industries and Regions.

In this image you see Dr Chris McDonough explaining to a group of farmers how soil amelioration leads to greater biomass production – but not necessarily higher carbon stocks.

View the webinar

From the webinar

Key themes

  • 1
    Step

    1. Soil Organic Carbon (SOC) is naturally low in Mallee soils

    SOC is critical for soil health, contributing to nutrient cycling, water retention, and overall soil structure. In the Mallee, there are two main reasons why SOC levels are relatively low (< 1%): i) low rainfall conditions mean less plant growth, so there are less carbon inputs to the system ii) soils are generally sandy with minimal clay content, meaning less protection for soil carbon, and its more rapid breakdown.
  • 2
    Step

    2. Minimise carbon losses!

    The first and most realistic goal in carbon management in Mallee soils should actually be to minimise carbon loss! When paddocks suffer wind erosion, a lot of what blows away is organic matter. Maintaining as much ground cover as possible to reduce erosion losses is one of the most important things a land manager can do – so no-till seeding and avoiding overgrazing are two essentials for good carbon management.
  • 3
    Step

    3. Maximise biomass production

    Maximising biomass production is not only profitable, but also improves carbon inputs to the soil – any agronomic strategies that boost crop and pasture production are good for soil carbon too. This can include optimised nutrition (conventional or organic amendments) but also actions like deep ripping to improve rooting depth and liming to manage acidity. In sandy soils, most of the extra biomass is quickly broken down, supplying nutrients to the next crop. Incorporation of clay into soils by delving, deep tillage or clay spreading can boost plant performance as well as the ability of soil to store organic matter.
  • 4
    Step

    4. Realistic goals for carbon management in the Mallee

    While methods have been developed to monitor soil carbon levels in agricultural soils, most registered projects are in higher rainfall zones, on soils with reasonable clay content, and involve perennial pastures and rotational grazing. There is very little evidence that registering soil carbon projects in the Mallee makes economic sense, particularly once the costs of registration, baselining and reporting are taken into account.

Findings

Maximising Carbon Efficiency and Soil Health in the Mallee

On most Mallee farms, optimised soil carbon management is is probably less about carbon sequestration, and more about protecting the carbon you’ve got, and maximising biomass production, soil health and nutrient cycling. Maximising yield per unit of input often reduces your emissions intensity (greenhouse gas emissions per kg of product), which is in itself a win for the environment!  Additional methods may also be developed that make soil carbon sequestration more feasible in the Mallee in future.

In the image you see wheat crops on a sandy loam in SW NSW – agronomic strategies that boost biomass production lead to better yields, lower emissions intensities, better ground cover and healthier soils.

 

Watch the Webinar for a Deeper Dive

These insights only are only a broad glimpse of the information covered in our webinar. Explore MSF’s Carbon in the Mallee webpage for the full webinar recording and additional resources on carbon management relevant to the Mallee.

Rate our resource

How useful was this post?

Click on a star to rate it!

Average rating 0 / 5. Vote count: 0

No votes so far! Be the first to rate this post.

Leave the first comment

Join the Conversation & Share with Your Community

Engage with fellow farmers by commenting on resources, sharing your experiences, and spreading valuable insights across your networks on Soils Connect.

Explore Key Categories

Building Soil Function

Strategies like ground cover and amelioration to enhance soil structure and fertility.

View more

Soil and Carbon

Exploring carbon farming practices to boost soil health and reduce emissions.

View more

Soil for Drought Resilience

Addressing land degradation challenges, including saline soils and Mallee seeps, to improve resilience to dry conditions.

View more

Soils and Cropping

Integrating soil management with agronomy for improved crop productivity and sustainability.

View more

Soils and Livestock

Optimising livestock and pasture systems to enhance soil quality and pasture performance.

View more

Frequently asked questions

Ask Charlie Carbon: Your Soil Questions Answered