Total Carbon

What is Total Carbon?

graphic of carbon cycle from the NOAA website

The Carbon Cycle. Photo Credit:

Total organic C is the portion of soil organic matter made up of organic C. Measurement is usually via high-temperature soil combustion. This property is of widespread interest due to the potential of the soil to sequester C that would otherwise contribute to climate change as CO2 in the atmosphere, as well as the importance of soil organic matter to local soil fertility. See soil organic matter and Active Carbon for more details.

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Regional Educator ResourcesOther Educator ResourcesTechnical Resources
Title Source Resource type and Date Short Summary / Preview
Soil Carbon Loss Proportional to Tillage Intensity No-Till Farmer News Article

Aug 2019


This article, featuring research from a retired USDA-ARS soil scientist, describes the soil carbon losses after varying tillage intensity in Minnesota, showing that increasing disturbance caused greater soil carbon losses.

Understanding and Perfecting Conservation Agriculture and Carbon Management in Your No-Till Operation No-Till Farmer Video

Feb 2019


Don Reicosky, retired soil scientist for the USDA-ARS in Morris, Minn., outlines the connection between conservation agriculture and soil health principles that are elevating the importance of carbon management.

Total Organic Carbon – NRCS & others Webpage

Sep 2011


Soil organic carbon is made up of a number of different pools that vary in their chemical composition and stage of decomposition.

Soil Quality Indicators: Total organic carbon USDA NRCS Fact Sheet

Oct 2009


Total organic carbon (TOC) is the carbon (C) stored in soil organic matter (SOM). Organic carbon (OC) enters the soil through the decomposition of plant and animal residues, root exudates, living and dead microorganisms, and soil biota.

Soil Organic Carbon Cycle Michigan State University Extension Fact Sheet

Aug 2018

Fact sheet about soil organic carbon and a handout for use with the video: CSCAP 0121 2012 VIDEO.
Title Source Resource type and date Short Summary
Organic Carbon Pools – Queensland Fact Sheet

Not Dated


Soil organic carbon is made up of a number of different pools that vary in their chemical composition and stage of decomposition.

Title Source Resource type and Date Short Summary
Understanding changes in soil organic carbon Purdue University Research Report

May 2019


Describes research from a watershed study site within the NSF-funded Intensively Managed Landscapes Critical Zone Observatory. The results show that in this setting, physical transport rather than biogeochemical transformation is the dominant driver affecting both the below-ground profile as well as the stocks of SOC.

The Sanborn Field Experiment: Implications for Long-Term Soil Organic Carbon Levels American Society of Agronomy Peer-Reviewed Publication

Jan 2011


It appears that an equilibrium level of SOC for some cropping systems takes about 30 to 40 yr to develop. Initial active carbon (AC) content assessment as a proxy for soil quality shows greater AC with manure and higher input management systems. The AC had a wide seasonal flux within a growing season as a function of temperature and moisture fluxes on microbial activity.

Soil carbon 4 per mille Geoderma Peer-Reviewed Publication

Apr 2017



A paper suggesting an aspirational global goal of increasing soil organic C at 4 per mille per year, and describing how different regions of the world might adjust agricultural management to attain this goal.

MCSE: Soil C and N Michigan State University Research / Extension Protocol



Protocol to measure soil C and N.

Total Carbonates in Soil Michigan State University Research / Extension Protocol

Not Dated


Protocol to measure soil carbon. The total carbon content of soils can include inorganic carbonates as well as organic carbon, and inorganic carbonates can interfere in the measurement of organic carbon using elemental analyzers.

This page reviewed by Liz Schultheis, Joe Rorick, and Anna Cates.

Last reviewed October 22, 2019