Know Your Soils #4: How to capture carbon in your soil

Know Your Soils #4: How to capture carbon in your soil
Welcome to the fourth instalment of our Know your Soils series sharing practical tips for monitoring the soil health on your land. Keep an eye out for our bitesize videos and fact sheets on simple tests you can do yourself on farm.

“If you can’t measure it, you can’t improve it.”

“If you want to capture carbon, you have to think like carbon!”
A special short episode of Farmerama Radio, a podcast sharing the voices of smaller scale farmers

Charles Schembre is a Soil Conservationist at the Napa County Resource Conservation District, working primarily in Vineyard Agriculture. He has received grant funding to set up his carbon farm plan project from California’s Healthy Soils Program, a scheme to support farmers with increasing
oil health, sequestering carbon and improving water retention.

Sequestering or increasing soil organic carbon is the process of plants absorbing carbon dioxide from the atmosphere, and transforming it into carbon in the soil through photosynthesis. This is beneficial for reducing greenhouse gases, in addition to increasing soil fertility.

Charles is working with farms and vineyards to create holistic ‘Carbon Farm Plans’, which assist them to increase their agricultural resilience and productivity, and mitigate the impact of our rapidly changing climate with sustainable farm management practises.

In this short episode of Farmerama, he explains how ‘Carbon Farming’ works, what a carbon farm plan is and how you can monitor this on your farm:

https://soundcloud.com/farmerama-radio/short-charles-schembre-on-carbon-farm-plans-monitoring-soils

You can see an example carbon farm plan from the USDA Napa County vineyard here.

Carbon sequestration is a win-win, right?
Yes, however, making a plan and monitoring it’s success is the challenge. The idea for the plan is to put all potential options in, and then chip away to find what’s realistic. In terms of soil health there are several different tactics he suggests you can use to increase carbon in your soil and monitor how they are working:

• No-till: This is the practise of not ploughing, leaving soil undisturbed, protecting against soil erosion and allowing microbes, fungi and worms to do their great work building soil health. This is one of the easiest practises to implement as it doesn’t involve much financial commitment, so a lot of the farms using carbon farm plans try it first.
• • Compost: Adding compost to the soil builds up it’s soil organic matter content. The benefits of this practise are much longer term. Charles recommends adding large compost applications to soil perhaps every 5 or even 10 years.
  • Ground cover: The more ground is covered in plants, the better. If you want to capture carbon, you need leafy green plants, absorbing CO2 from the atmosphere and putting it into the ground. So those, ‘untidy areas’ of the farm, rife with riotous plants and weeds, might actually be doing your soil a favour. Think twice about topping them next time!

Soil monitoring

• To understand how much carbon sequestration you are achieving Charles advises you start monitoring these three soil health indicators (identified by Soil Health Institute):
  
  • Wet aggregate stability (Slake test): this is the soil’s ability to withstand disintegration from water erosion. You can do the slake test at home! (our soil health expert Jenni Dungait will tell us more about this later in the series)
  • Bulk Density: this is the unit of dry soil & air per unit of bulk volume. It changes depending on different land management practises. The test is best done in a lab, and involves drying a soil sample in an oven at 105 degrees for 18-24 hours.
• • Soil Organic Carbon: this is a part of soil organic matter which is traditionally measured with the Loss-on-ignition test (also best done in a lab). However recent research by Soil Health Expert Jenni Dungait has shown that the wet aggregate stability test (or slake test) is a proxy for Soil Organic Carbon when following this protocol.
• • There has already been a proven reduction in greenhouse gases on several of the farms using carbon farm plans. Do you think you can make your own carbon farm plan? Check out Charles’ Carbon Farm Plan for their demo vineyard, Huichica Creek.