Understanding the Role of Irrigation in Soil Carbon Projects

The first step, engage your local farm advisor!

First things first… if you’re looking at undertaking a soil carbon project, we strongly suggest engaging the services of your local farm advisor! They ultimately will understand which farming practices work best to build soil carbon in your region and can advise on how to set up your project for success!

Now back to the irrigation!

Irrigation design and management can have a direct effect on both a farm’s crop yield and the soil’s carbon storage capacity. Irrigation methods vary considerably depending on your land, soil, ecological factors, your crop, and what stock you have. When low natural rainfall is limiting your crop productivity, irrigation is a good asset for your soil carbon toolbox.

Basically, when irrigation is designed and managed efficiently, the soil becomes far more conducive to microbial life, which in turn, increases the activity of microbes, and results in greater carbon storage and water holding capacity.

In low-rainfall climates particularly, adding precision irrigation to the picture can be the ticket to building carbon in your soil, hence resulting in carbon credits in the bank, better-performing crops, and increased overall resilience (win-win!). 

Something to note…Research has shown soil organic carbon stock has increased in the shallow soil depths, while deep soil carbon storage from irrigation is still being understood That’s why we suggest engaging with your local farm advisor to discuss the ins out outs of irrigation to build soil carbon! 

So, what does the ACCU Scheme method say?

According to the ACCU Scheme’s Soil Carbon Method, “undertaking new irrigation” is considered an eligible practice for your farm (you can see the full list of eligible practices here). It essentially involves applying new or additional irrigation to your property by improving the efficiency of on-farm infrastructure or management practices within your project area. 

It’s important to note that there are some restrictions around the application of irrigation. For example, you cannot increase the amount of annual or five-year irrigation over a CEA or the project area by more than 20% of that amount used during your 5-year baseline period. So, you can’t simply purchase an additional water licence and start ramping up your water use to increase carbon.

So, what irrigation techniques should I look into?

Adopting precision irrigation technologies

Adopting efficient and effective irrigation methods through precision irrigation means only using the necessary amount of water required for the context of your farming system, reducing excess water use. 

Using consultants such as Certified Irrigation Designers, you can set up the best irrigation system for your management plan, and make sure it satisfies the Soil Carbon Method’s irrigation eligibility requirements.

Other Activities to enhance the hydrology of the landscape

Landscape activities

Techniques such as building leaky weirs or chain-of-pond streams, contour banks, and other erosion control techniques can help increase the water hydrology of your property by slowing water movement through the landscape.

Vegetation activities

Similar to landscape activities, planting deep-rooted trees and shrubs strategically can help slow the movement of water underground and increase the access to water in dry periods, as well as assist in salinity control.

Check out the landscape rehydration work being done by the Mulloon Institute at a Western Australian property here.

Further reading

• Water Management Resources from WA’s Department of Ag
• The Mulloon Institute’s Landscape Rehydration Initiative
• ANU research coverage – Irrigation helps beat the heat of global warming

Ready to find out more?

Explore our range of educational resources in our Carbon Farming Education Hub where we frequently publish educational articles, webinars, and guidebooks. 

When you’re ready to explore the feasibility of undertaking a carbon project on your property, email us at [email protected] or give us a bell at (08) 6835 1140 to be connected with one of our project facilitators.