Did you know that 9% of California’s greenhouse gas emissions come from the agricultural sector? But environmentalists, scientists, and farmers are identifying farming techniques that actually remove carbon from the atmosphere and sequester it, not just offsetting agricultural emissions but also drawing down excess CO2 created by other activities. 

A Very Brief History of Agriculture in the United States

Corn and other crops were cultivated by Indigenous peoples in North America for more than 7,000 years before the arrival of the first English settlers. This agricultural knowledge was passed along in the 1600s when the Wampanoag native residents taught the English colonists how to clear land, till fields, and grow the corn that was crucial to their initial survival.

While the agricultural practices of the Native peoples were sustainable for thousands of years preceding the colonists’ arrival, the adoption of new farming methods by subsequent waves of settlers changed the ecological context considerably. During the 1800’s, many practices intended to increase crop yield became widespread including fertilization, use of pesticides, irrigation, and the use of gas-powered tractors. While these developments increased productivity, they also damaged the health of the soil. Moreover, destruction of vast areas of grassland in the Midwest eventually led to the catastrophic loss of topsoil during the drought and subsequent dust storms of the 1930s. 

	Fun fact:  It takes 300 years to form 1 inch of agricultural topsoil

This crisis prompted some attempts by federal and state officials to identify techniques for promoting the health and fertility of agricultural soil. However, by the 1970s it had become clear that the nation’s enormous agricultural productivity had been achieved at the expense of a wide range of environmental consequences. To understand what happened let’s review a little chemistry.

The Chemistry-Phobe’s Guide to Carbon

I tend to zone out when anyone talks about chemicals. I admit that Chemistry was my least favorite class in school. I developed a huge mental block concerning the term for the basic unit of measurement in chemistry: “mole.” And believe me it’s hard to succeed in chemistry class if you keep picturing the wrong kind of mole. But bear with me, we can do this.

According to UC Davis researcher Jessica Chiartas, “The soil represents a huge mass of natural resource under our feet. If we’re only thinking about farming the surface of it, we’re missing an opportunity. Carbon is like a second crop.” Why is she so excited about carbon?

Carbon is a chemical element like hydrogen or nitrogen. It is a basic building block of biomolecules and is found in all organic matter. Carbon exists on Earth in solid, dissolved and gaseous forms. 

Under the earth’s surface, carbon is stored in fossil fuels like coal, oil, and natural gas as well as in some kinds of rocks. When fossil fuels are burned, the carbon they contain is released into the atmosphere as a gas (carbon dioxide or CO2), where it traps heat and contributes to global warming. Decomposing organic matter on the surface of the earth also releases CO2 into the air.

Now take a look at the ocean. The ocean is a carbon sink (or repository) because it absorbs CO2 from the atmosphere. However, this absorption also makes the water more acidic. The amount of damage done depends on the balance of these conflicting processes.

Now let’s get to the sequestration of CO2 in biomass (i.e., plants, trees, and algae). You may or may not remember that photosynthesis is the process of using light energy from the sun along with CO2 and water in the atmosphere to make food for plants, trees, and algae. When the greenery dies, the constituent carbon becomes part of the soil. 

We can support this sequestration process by improving the health of the soil used in agriculture. When soil is healthy, plants grow to their maximum productivity and are thus better able to absorb and sequester carbon so that it doesn’t go back into the atmosphere in the form of CO2.

Source: US Dept of Agriculture

How Can Farmers Give a Boost to Carbon Sequestration?

Farmers are uniquely positioned to assist in drawing down CO2 from the atmosphere. I was surprised to learn that plants are better suited for this sequestration than trees. Unlike trees, plants sequester most of their carbon underground. Even if the plant burns, the carbon stays fixed in the roots and soil. So, while forests have the ability to store more carbon, grasslands are more resilient in unstable conditions created by climate change.

For this reason, scientists and farmers are becoming more and more excited about the possibilities of soil-based carbon sequestration.

After all, 40% of land in the United States is farmland...an abundant storage area for carbon! 

That is some good-looking soil!

Effective Practices for Creating Healthy Soil

Conventional agricultural practices typically involve stripping the soil of all plants other than the primary cash crop, usually with the assistance of pesticides and aggressive tillage. The alternative is to encourage the growth of diverse plant life in addition to the primary crop. Here are several ways to do that.

Cover cropping. Cover cropping refers to seeding fields between harvests. Cover crops may include either a single species or a mix of seasonal grasses and other plants. As explained by the Fibershed Carbon Farming Education program, the roots from the cover keep the topsoil in place and aerate the soil as they penetrate it, helping the beneficial microbes, fungus, bacteria and worms in it thrive. This healthy soil also promotes the abundant growth of the primary cash crop. 

Planting windbreaks. Planting native trees and shrubs creates a barrier to prevent the wind from drying out the soil and blowing it around. They also provide wildlife habitat and resources for bees and other pollinators. 

Rotational grazing. After crops have been harvested, farmers can allow animals to graze in the fields in order to remove some of the dried-out, dying remnants and allow weeds and other green plants to emerge. These little green interlopers reduce fire risk and increase carbon sequestration.

A cover crop of poppies in a vineyard in Sonoma County		Planting windbreaks		Rotational grazing in Marin

Opportunities for Change

Here in California, several important programs have been developed to assist farmers and ranchers develop a plan for enhancing the potential of their land to sequester carbon. One of these is the Healthy Soils Initiative, which helps farmers increase carbon sequestration by supporting their efforts to improve plant health and crop yields, increase water retention by the soil, and prevent erosion. 

Another important initiative is the Carbon Farming Network. The Network is a coalition of support organizations and land trusts along with 41 of California’s 96 Regional Conservation Districts. These districts work with farmers, ranchers, and foresters to maximize carbon storage in soils by implementing regenerative land management practices based on local conditions. The Network sponsors trainings and workshops to share information and facilitate peer-to-peer learning among its practitioner members. They are particularly attuned to the needs of farmers from marginalized groups, including women and people of color. The Network has facilitated the completion of 57 carbon farm plans to date, encompassing approximately 46,000 acres across the state.

 

What Can You Do?

Consider patronizing businesses that follow the sustainable farming practices associated with healthy soil. One sterling example is Coyuchi, a purveyor of organic bedding, towels, and apparel that supports regional farms and ranches. Based in Point Reyes, Coyuchi has partnered with Fibershed to support “carbon farming practices that actively reduce greenhouse gas emissions, creating climate beneficial fibers.”

Another choice you can make is to buy organic dairy products from local farms. Orchard Valley operates as a collective of small farms across the country. Long committed to sustainability and high animal care standards, they recently secured funding to help member dairies develop methods to increase carbon sequestration and reduce green-house gas emissions. Straus Family Creamery is located in the town of Marshall on the site of a dairy farm established by Bill and Ellen Straus in the 1940s. In the 1980s, their son Albert Straus converted the farm to an all-organic operation and founded the first 100% certified organic creamery in the country. Today, products from the Creamery all come from the Straus farm itself or one of 12 other organic, family-owned farms located in Northern California. I myself am extremely partial to their whole milk Greek yogurt!

Click on this "buy direct" link supplied by Soil Centric  to purchase from other producers that use regenerative farming and grazing practices. 

One final note: Recently the EFM sponsored a webinar on Healthy Soils as part of the Forum 2020 program. I was educated and inspired by the presentations. Thanks so much to presenters Renata Brillinger of CALCAN, Cynthia Daley of the Center for Regenerative Agriculture, and Jeff Creque of the Carbon Cycle Institute, to moderator Diana Conlon of Soil Centric, and to emcee Anne-Christine Strugnell of the EFM for their fascinating insights into the issues and solutions in this important area. Please contact Kim Rago at kim@marinefm.org if you are interested in viewing a video of the webinar. 

That’s it for this installment of the EFM Notebook. As always, please feel free to contact me with questions, comments and suggestions: susanh@marinefm.org.

As usual, thanks to Rob Badger and Nita Winter for sharing Rob’s beautiful image on the Notebook banner. Check out their award-winning book on wildflowers or visit their website to see more birds, flowers, and other images.