Note: This metric replaced the previous Soil Health metric for all customers on 27 July, 2023.
What is the updated Soil Health metric?
The Soil Health metric measures the impact that a product’s ingredients have on the organic carbon content of the soil in which they were grown. It takes into account the change in soil organic carbon as a result of growing an ingredient, along with its expected yield and ingredient concentration based on its origin location. An increase in soil organic carbon is an indicator of soil health improving, whereas a decrease in soil organic carbon indicates that soil health is degrading.
How does soil health relate to agriculture, product development, and the food system?
Soil is an essential building block in all agricultural ecosystems, as the home to incredible macro and micro biodiversity. Healthy soil will grow nutrient-dense plants, protect against erosion, and capture carbon from the atmosphere.
Carbon is also an essential building block of life and a component of all plants and animals on Earth. Carbon that is not held in rock or deep in the oceans is constantly changing and moving throughout the carbon cycle. Soil holds the largest portion of active carbon on earth. Plants absorb carbon from the atmosphere and convert it to plant tissue, some of which returns to the soil as plant residue. This is how carbon is captured and stored in the soil, in the form of soil organic carbon.
Soil organic carbon is the measurable, carbon component of soil organic matter. It is a widely recognized indicator of overall soil health, because it promotes soil structure, aeration, water retention capacity, nutrient retention and degradation of pollutants. Agricultural overproduction results in soil organic carbon being released into the atmosphere, degrading the structure and biodiversity of the soil. The root systems which hold soil in place can disintegrate, which leads to erosion, water scarcity and desertification.
Healthy soil is dependent on the variety of organisms it contains — a network of microorganisms, root systems, and decomposing matter. Plants and their root systems are also one of the most effective natural carbon sinks, a critical tool in fighting climate change.
What are the biggest contributors to negative soil impact?
Annual monocropping, the practice of planting the same crop season after season, degrades the soil significantly and therefore requires higher and higher amounts of fertilizer to continue to produce.
Tilling—the practice of overturning soil in order to plant seeds and distribute fertilizer—destroys the network of organic matter in the soil, exposing it to heat and wind causing it to dry out.
Overgrazing of livestock on the same pasture without giving the land a break leads to compacted, parched, soil that is baked out in the sun without any natural protection from grasses and other vegetation.
How do we measure Soil Health impact?
The Soil Health metric calculates the change in soil organic carbon as a result of growing an ingredient, taking three factors into account:
Change in soil organic carbon as a result of growing an ingredient
The amount of soil organic carbon, measured during soil samples taken at a depth of 30cm over the course of one year before and after a crop has been grown. These measurements are consistent with the dichromate oxidation method (commonly referred to as Walkley-Black) and the loss on ignition method (commonly referred to as the combustion method) used to quantify soil organic carbon.
Where customers can provide company-specific soil measurements via our agricultural practices survey, we can integrate this data into our measurements to provide a more specific Soil Health assessment. For customers who don’t have access to this information, we will assign a default value based on peer-reviewed scientific research, and the provided or most likely sourcing location for the crop.
Expected yield of the ingredient
The expected yield, depending on the location and agricultural practices associated with growing the ingredient. Specific agricultural practices can be integrated via our agricultural practices survey, if known.
Ingredient concentration
The volume of raw material that is needed to be grown to produce one unit of finished ingredient.
The metric is measured in megagrammes / tons of organic carbon per kilogram of ingredient over a one-year period:
Soil Health = Mg C kg -1 y -1
How can I improve impact as a product developer?
For animal-based ingredients, assess the feed mix provided to the animals that were grown or raised to produce the ingredient. Feed production is an important contributor to environmental impact, and selecting ingredients that have received a feed mix that has a greater proportion of high quality pasture/grassland-based feed, compared to lower quality monocrop feed (such as conventional corn) will improve soil health impact.
For animal-based ingredients, consider the animal husbandry practices associated with raising the ingredient. Animals that are raised on pastured systems with minimal to no soil tillage will have a better soil health impact than those raised in industrial systems.
For plant-based ingredients, consider the production practices associated with growing the ingredient. Crops that are grown using minimal tillage, especially those that incorporate other soil-friendly agricultural practices such as cover cropping, will have a better soil health impact than those grown using conventional monocropping.
Key Data Sources
Nijdam et al., The price of protein: Review of land use and carbon footprints from life cycle assessments of animal food products and their substitutes. Food Policy, Volume 37, Issue 6, 2012, Pages 760-770.