How Alive is my Soil?

Excerpted with permission from Soul Fire Farm‘s Guide to In-Field Soil Health Measurement Protocols
with Strategies for Building Soil Health to Call Carbon Back to the Land

As European settlers displaced Indigenous people across North America in the 1800s, they exposed vast expanses of land to the plow for the first time. It took only a few decades of intense tillage to drive around 50 percent of the original organic matter from the soil into the sky as carbon dioxide¹.

Agriculture continues to have a profound impact on the climate; along with forestry, deforestation, and other land use, it contributes roughly 24 percent of global greenhouse gas emissions².

The good news is that regenerative agricultural practices like minimal soil disturbance, organic production, compost application, the use of cover crops, and crop rotation as well as silvopasture systems that integrate nut and fruit trees, forage, and grasses can harness plants and soil to put carbon back where it belongs.

Our duty as earthkeepers is to call the exiled carbon back into the land and to bring the soil life home.

Larisa Jacobson, Northeast Farmers of Color Land Trust

Soil is a living porous system made up of mineral and organic particles that interact with animals, fungi, bacteria, plant residue, water, and gases. Soil health refers to how well the soil is functioning from biological, physical, and chemical perspectives. Soil health impacts the quantity and quality of what we can produce on our farms and in our gardens, and it also affects how much carbon gets stored in the soil versus how much is released into the atmosphere. The amount of organic matter present in a soil (soil organic matter) is the foundation for how healthy a soil is. Soil organic matter is made up of approximately 58 percent carbon.

Since life is carbon based, carbon-containing molecules are a highly dynamic component of the soil ecosystem that is constantly changing forms. Plants take carbon dioxide out of the atmosphere, plant-derived organic carbon makes its way into the soil through root and litter inputs, life within the soil uses those inputs as food and energy to sustain their lives (decomposition), which leads to some of that carbon being released back into the atmosphere as carbon dioxide.

Taking a close look at the soil to understand its vitality and fertility isn’t new. Long before the western study of soil science, Indigenous communities practiced–and still practice–methods of evaluating soil health, using characteristics like color or the presence of specific plants or insects that tell us something about the system as a whole. Based on these practices, soil scientists have created tests we can perform in the field to observe and measure signs of life.

The guide How Alive is my Soil? presents soil testing methods that can be performed in the field by farmers, gardeners, or anyone who desires to understand and appreciate soil from a different perspective. While these tests aren’t intended to be a replacement for sending soil to a lab, they can be considered complementary to annual or biannual lab analysis.

In order to build soil health to grow flourishing plants (and people) and to store organic carbon, we first need to know what we’re working with. Maintaining a vibrant ecosystem in healthy soils or welcoming life back to degraded soils begins with an evaluation of existing conditions. Learning how to measure soil health helps to build an understanding of and appreciation for the natural processes taking place. Identifying constraints that aren’t obvious by day-to-day observation provides information to support management decision making.

[1] Soil Organic Matter in Temperate Agroecosystems: Long Term Experiments in North America,
eds. Eldor A. Paul et al. (CRC Press, 1996).
[2] Gensuo Jia et al. “Land–climate interactions,” in Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems, eds. Valérie Masson-Delmotte et al. (Intergovernmental Panel on Climate Change, 2019), 133, https://www.ipcc.ch/site/assets/uploads/sites/4/2019/11/05_Chapter-2.pdf.

The tests included in the guide can be performed in the field. The Earthworm Count, Infiltration, and Slake tests can be done with tools found at home or at a hardware store. The Soil Color, Soil Hardness, Microbial Biomass, and Soil Respiration tests require specialized equipment that can be found online from specialty dealers or from a lab.

The guide also presents management practices that are known to build and maintain soil health and store more organic carbon. Take what interests you and will work for your farm and available resources.