SNAPP: Developing targets to manage soil organic matter for environment and people

The Sustainable Development Goals (SDGs), adopted in 2015, establish a clear mandate to manage the planet for both human and environmental wellbeing. Any viable approach to achieving the SDGs requires addressing soil, which is the foundation of both healthy natural and agricultural ecosystems. Soil organic matter (SOM) is an especially important soil property because it is the principle arbiter of soil health and is one of the most responsive soil properties to land management. Management of SOM can increase agricultural productivity (SDGs 1, 2), remove carbon (C) from the atmosphere (SDG 13), and ensure water systems that are safe for human consumption and that support thriving aquatic biodiversity (SDGs 6, 14). Some forms of land management can degrade SOM, causing release of large quantities of C to the atmosphere, lower soil productivity, contaminate drinking water with excess farm nutrients, and cause eutrophication of aquatic ecosystems, which leads to biodiversity declines. Successfully managing soils for environmental and human wellbeing requires reliable estimates of how much SOM can be built up at any given site and how much SOM is needed to achieve target outcomes for nature and people. In this project, we will synthesize existing data to develop global estimates of how much SOM can be built up under ideal conditions. We will use these broad-level targets as a starting point to develop site-specific targets for SOM build up, and then quantify the relationship between SOM management and human and environmental outcomes for two projects within The Nature Conservancy—1) carbon sequestration and sustainable livestock production in California rangelands and 2) crop yield and nutrient and sediment retention through the Soil Health Partnership in the U.S. Midwest. We will then develop specific strategies for each program to integrate soil-based targets into their activities.