Cool Soil Initiative

WHY THIS PROJECT WAS NEEDED

In 2018, Riverine Plains and Central West Farming Systems partnered with Mars Petcare to develop an industry program called the Australian Cool Farm Initiative, to quantify greenhouse gas (GHG) emissions from wheat production, and to identify avenues to support farmers in reducing emissions, with a focus on soil health.

Technical support for this project was provided by the Sustainable Food Lab, an international agency with experience in supporting effective sustainability projects across supply chains.

The program was renamed the Cool Soil Initiative (CSI), in recognition of the role soil health plays as a key driver in mitigating GHG emissions on farm, while supporting increased system resilience across variable seasonal conditions. Kellogg’s, Manildra Group, Corson, Allied Pinnacle and Pepsico also joined the project, with Charles Sturt University providing research and administration support. Additional funding was provided through innovation hub, the Food Agility Cooperative Research Centre (CRC).

In short: This program aimed to create a platform for the food industry to support grain farmers in the reduction of GHG emissions, leading to increased long-term sustainability and yield stability, through the adoption of innovative agronomic strategies to increase soil health and related function.

The Cool Soil Initiative supported engagement within the Riverine Plains and Central West Farming Systems regions, with the geographical gap between the two regions spanned by FarmLink Research. The program supported informal peer learning within each region and also supported farmers to trial new practices and strategies.

The support of Charles Sturt University, through the Graham Centre for Agricultural Innovation, and additional funding through the Food Agility CRC, enabled additional research activities that provided further value to the project. This included better spatial estimates of soil carbon, the refinement of soil sampling methods, the provision of spatial data to participating farmers, and how to capture the economic value of practice change on farm.

The Cool Farm Tool, an online GHG calculator that is used to predict GHG emissions on each paddock, was also reviewed. 

How the project worked for farmers

To calculate on-farm GHG emissions, participating farmers shared paddock input data with their respective farming group, who then anonymised the data before adding it to a collective dataset. 

Farmers who participated in the program received GPS located soil testing services on up to 5 locations on their farms each year, along with technical support for interpreting Cool Farm Tool results and soil tests. Farmers also received advice on management options that addressed key limiting factors in their farming systems, focussed on recommendations that resulted in productivity, managing weed resistance, water availability in dry years, and short and long-term carbon benefits.

This program was the first of its kind in Australia, connecting farmers with end users in support of the industry. Through Riverine Plains and Central West Farming Systems (CWFS) in 2018, this project originally aimed to provide connections with farmers located within the area of supply to the Mars Petcare, Bathurst and Wodonga factories. In 2020 the program evolved to become the Cool Soil Initiative (CSI), with Kellogg’s, Manildra Group, Allied Pinnacle, Mars Petcare, Charles Sturt University and the Food Agility Cooperative Research Centre (CRC) participating partners. As such, this project connected across the supply chain in a unique pre-competitive partnership of corporate investment to provide benefit across the cropping industry.

The reach of farmer engagement also increased, with FarmLink joining the program in 2020, and the Irrigated Research and Extension Committee (IREC) coming on board in 2021 to support irrigated farmers in the Murrumbidgee Irrigation Area (MIA)/ Coleambally Irrigation Area (CIA). The emphasis in dryland systems focused on wheat production, while the irrigated systems of the MIA/CIA focused more on maize and soft wheat production. In 2022, Corson joined the program, expanding the reach further into maize production on the Darling Downs.

Farmer engagement was a key component, with each farming group supporting members and the community to participate in the project, at the same time as advocating to ensure that the project continues to deliver value back to those involved. Across the CSI project, farmer participation grew from 20 farmers in 2018 to 185 farmers in 2022.

Project outcomes 2022

Aim

The Cool Soil Initiative aimed to increase the long-term sustainability and yield stability of the grain-producing regions of southern NSW and northeast Victoria, through the adoption of innovative agronomic strategies and enhancing understanding of greenhouse gas (GHG) emissions to increase soil health and related function.

Method

Forty-five growers in the Riverine Plains region participated in the Cool Soil Initiative in 2021—22 with an additional 10 participating in the maize part of the program.

All participating growers identified up to five wheat paddocks each season for inclusion in the project, with GPS-located soil tests (0–10 cm) taken for each paddock. Each soil sample was air-dried and analysed for a range of soil properties, including soil pH (CaCl2), soil organic carbon (SOC), cation exchange capacity (CEC) and nutrients. Soil samples were taken from specific locations in each paddock based on ease of access and the known location of representative soil types.

Anonymised soil test results, farm input data and yields are captured in a simple database and processed through the Cool Farm Tool, which generated predictions of greenhouse gas emissions for each paddock.

The wet season of 2022 made soil sampling quite difficult. As a result, not all sampling results were available at the time this article was published. The combination of a delayed, wet harvest and a rebuild of the data entry system has meant that data collection from the 2022 season was also not available in time for this article.

How are emissions calculated?

There are two ways to consider GHG emissions on-farm. The first is to consider the whole farming system, which is highly complex, and considers the emissions footprint required to grow crops, cut hay, grow livestock, feed grain to livestock, tree plantings etc. At present there are no straight-forward tools available for farmers to generate this information, so this is still a future focus.

The second way is to consider the energy/emissions footprint required to grow each commodity, which considers the energy and related emissions connected to each input. This method is used for any supply chain reporting, whereby farmers can demonstrate that the commodity is produced with a low emissions footprint. This is the approach taken in the Cool Soil Initiative, with farmers provided with the emissions footprint for their grain grown on a per tonne, and per hectare basis. This approach is internationally recognised, with standardised methods.

The emissions footprint of grain, or any commodity,is reported on a CO2e basis (carbon dioxide equivalents), which is based on the GHG emissions related to the manufacture and use of all crop inputs (fertiliser, crop protection, weed control), energy/diesel usage and soil disturbance. Nitrogen usage is of particular interest, as:

• The manufacture process for urea is highly energy intensive, with high GHG emissions
• The addition of urea results in N2O and CO2 losses from the soil
• Urea is generally the single largest input.

All of which means that urea application is a significant driver of emissions.

So, while accurate on-farm emission reporting for Australia is a moving target, the Cool Soil Initiative contributed to refinement of the methods and calculations, to improve the relevance and accuracy of internationally relevant emission calculations for the Australian systems. As new learnings are generated over the coming years, all on-farm emission calculations will be re-run, to ensure farmers have access to the most accurate figures available.

Results

Figure 1. Displays the emission intensities per tonne of wheat grown, while Figure 2 shows GHG emissions per hectare. The data is represented as box plots, the centre line in each box showing the median, the box showing 50% of the values, and the lines and dots showing the degree of variance. If a value is below 0, the emissions associated with the production of that crop are less than the offsets.

Figure 2. GHG emissions per hectare (CO2e/ha) for wheat grown in the Riverine Plains, FarmLink and Central West regions.

Soil carbon values

Soil carbon values are an important parameter in the emissions calculation, providing significant offsets. However, more importantly, they are a crucial consideration in understanding the resilience of the farming system, as higher carbon values mean higher amounts of soil organic matter, which means greater nutrient cycling, greater water-holding capacity, and greater diversity of microbes.

The range of soil carbon values measured in this program far exceeded expectations. As these values are GPS-referenced, they represent measurements at a single point in the paddock, rather than averaged samples taken from across the paddock. This also means they can be tracked over time.

The soil carbon values vary significantly both within, and between regions. As each value on the graph represents a paddock in the program, the crop-data relating to each value can be used to understand if there are any similarities between points. This data has been assessed to specifically understand if there are simple similarities between the points at the high end of each curve.

Figure 3. Soil organic carbon (SoC) (%) values (0-10cm depth) from 827 paddocks across three regions, sampled from 2018-2021. Median values for each region are: Riverine Plains SOC = 1.51%, FarmLink SOC = 1.36%, Central West Farming Systems (CWFS) SOC = 1.07%.

While the ongoing economic component of the program will continue to pull out more detailed relationships, the key similarities that came out from each region are listed below:

• Riverine Plains: 35 paddocks had SOC > 2%. Of these, 26 had a history of a pulse or pasture phase. All yielded well in 2021, unless they experienced waterlogging. 
• FarmLink: 12 paddocks had SOC > 2%. Of these, nine had a history of lucerne, clover-based pasture or pulses. Only one paddock had a pH value < 4.8. 
• CWFS: 20 paddocks had SOC > 1.5%. Of these, 15 had a history of lucerne or clover-based pasture, only 1 with pH <4.8 and good yields in 2021 (unless flooded).

The role of legumes in the system were also well highlighted. When farmers grew a legume in 2019 in both CWFS and Riverine Plains, the wheat yield in 2020 was consistently high, with a tighter range of yields, compared to a broad spread of yields when they did not. This trend was not clear in 2021, likely due to yield penalties due to the wet harvest, and less legumes grown in 2020 due to likely emphasis on crops with strong commodity pricing, to recoup the poor returns of the drought years.

The common themes from this very basic assessment, is that there is a strong connection between the background soil fertility, SOC values and yields. This is a key area of interest for the program, which we will continue to explore further.

Conclusion

The Cool Soil Initiative is a pre-competitive, collaborative approach to understand the key drivers of on-farm emissions, while supporting the food industry partners to learn more about the farming systems that produce their grain. Farmer engagement and feedback is pivotal to the success of this program, with farming system groups providing strong support and advocacy for participating farmers. 

Acknowledgements

Riverine Plains acknowledges the investment for this year’s results by Mars Petcare, Kellogg’s, The Manildra Group, Corson, Allied Pinnacle, Charles Sturt University and Food Agility CRC, as well as the project support from the Sustainable Food Lab (SFL). Thankyou also to all our farmer co-operators, whose support for this project is greatly appreciated.

Authors: Dr Cassandra Schefe, Agrisci Pty Ltd; Jane McInnes, Riverine Plains.

Project outcomes 2019-2022

• Annual reports on the project have been published in Research for the Riverine Plains, 2020, 2021 and 2022.
• Read our farmer case study.

Cool Soil Initiative partners, the Kellogg’s Group, have also produced an information document about the program and how the project is working with farmers to reduce greenhouse gas emissions. 

Next phase of the Cool Soil Initiative 

From 2024, the Cool Soil Initiative will have a dedicated person working directly with farmers across northeast Victoria and southern NSW, filling the role previously undertaken by Riverine Plains.

Dr Cassandra Schefe will continue to be hands-on in the region, working closely with CSI farmers to analysis soil health and GHG results and identify opportunities for innovation and practice change.

To find out more about the Cool Soil Initiative, phone 02 6933 2220 or email coolsoil@csu.edu.au. Further information about the project is also available on the official project website.