Soil Carbon Storage In Grain Systems

Uncovering the hidden potential of the soil ecosystem

Grain stubble remaining after harvest at Karoonda, SA

Soil can contain up to twice the amount of carbon stored by the atmosphere and up to three times that stored in vegetation. Growers have known for centuries that improving the soil by adding organic matter in various ways provides a range of benefits and is an essential part of appropriately managing the soil that supports crops and plants.

The benefits are numerous and include better use of available nutrients, increased water holding capacity and improved plant health and yields.

The Grains Research and Development Corporation (GRDC) is undertaking a multi-year program to build the capacity of the grains industry to make the most of the benefits and adoption of practices that increase soil carbon.

The GRDC's Soil Biology II initiative is based on the idea that soil health and quality are major determinants of crop productivity in the short and long term. The initiative aims to equip researchers and growers with tools and resources for better management of nutrient inputs, enable suppression of soil-borne diseases with minimum chemical input, and improved information on what makes a "quality" soil. 

This project seeks to explain how different microbes affect soil carbon consumption and storage in a diverse range of agricultural settings - Associate Professor Brajesh Singh, Project Leader

This component project entitled "Soil Carbon: Identifying Microbial Drivers And Key Modulators In Grain Cropping Systems [P00020995]" is designed to find out how different soil types, nutrients and microbes interact with carbon in the soil to impact grain system productivity.

The project is based at three sites with different soil and cropping environments to assess how the soil microbial environment affects carbon sequestration and turnover and how best we can manage the available inputs to sustainably drive effective use of the soil carbon resource.

^ Back To Top 

The Roles of Microbial Communities In Driving Soil Carbon Cycling

Specifically, this project is interested in understanding the role of soil microbes in the processes within soils that drive soil carbon capture and retention.

We know that changes in land management practices affects carbon sequestration but we need further research to fully understand the processes used by soil microbes that determine the capture of carbon from plants to soils. Through this research, we will outline how microbes in soils regulate the cycling of soil carbon within grain cropping systems with the particular aim of implementing practices that enable soil microbes to influence increased grain crop productivity and sustainability.

Direct Action Policies and Soil Carbon

The Federal Government's Direct Action Policy recognises the opportunities in agriculture and forestry to mitigate carbon emissions on a direct basis.

Understanding the dynamics of soil carbon and the processes involved is a crucial component of managing emissions against drawdown of atmospheric carbon.

Building soil carbon levels offer potential not just for managing greenhouse has emissions but also building the microbial health of soils and contributing to ongoing farm productivity and sustainability initiatives.

With direct benefits to farm productivity in the form of increased yield and plant and soil health, applying a detailed understanding of soil biology science represents a significant opportunity to determine the link between microbial action, soil carbon use and cropping system productivity.

^ Back To top 

Important Questions

Industry and science still have numerous questions that need more explanation. Practices such as direct drill and no-till farming are widely adopted and these practices promote retention of soil carbon in some but not all soils. We know that microbes play a central role in cycling soil carbon by decomposing organic matter into stable forms of carbon in the soil but the exact processes and the extent to which they control these processes under different soil types and conditions is not fully understood.

The variability of responses to these practices is most likely to come from the interaction between soil structure and availability of nitrogen on microbial action. Soil carbon is protected within the soil either by adsorption to organic/inorganic clay surfaces or by entrapment in soil aggregates which are inaccessible to degrading microbes and extracellular enzymes. 

Through this project, the Institute will provide insights into:

  • How changes in soil structure under different cropping regimes impacts on physical, chemical and biological properties of soils and their microbial communities
  • How different classes of microbes - bacteria, fungi and mycorrhiza - within soil aggregates affect availability of nitrogen and carbon
  • How this understanding can use data and evidence to create models that enable us to better predict soil carbon processes in agricultural systems at much larger scales

 Aims & Objectives Of The Project »