Associated Particle Imaging for Soil Carbon
Plants capture atmospheric carbon dioxide (CO2) using photosynthesis, and transfer the carbon to the soil through their roots. Soil organic matter, which is primarily composed of carbon, is a key determinant of soil’s overall quality. Even though crop productivity has increased significantly over the past century, soil quality and levels of topsoil have declined during this period. Low levels of soil organic matter affect a plant’s productivity, leading to increased fertilizer and water use. Automated tools and methods to accelerate the process of measuring root and soil characteristics and soil properties, as well as the creation of advanced algorithms for analyzing data can accelerate the development of field crops with deeper and more extensive root systems. Crops with these root systems could increase the amount of carbon stored in soils, leading to improved soil structure, fertilizer use efficiency, water productivity, and crop yield, as well as reduced topsoil erosion. If deployed at scale, these improved crops could passively sequester significant quantities of CO2 from the atmosphere that otherwise cannot be economically captured.
Project Innovation + Advantages:
Lawrence Berkeley National Laboratory (LBNL) will develop a field-deployable instrument that can measure the distribution of carbon in soil using neutron scattering techniques. The system will use the Associated Particle Imaging (API) technique to determine the three-dimensional carbon distribution with a spatial resolution on the order of several centimeters. A compact, portable neutron generator emits neutrons that excite carbon and other nuclei. The excited carbon isotopes emit gamma rays that can be detected above the ground with spectroscopic detectors and used as a proxy to estimate the amount of carbon in the soil. Neutron exposure at the applied rates from the instrument will not damage plants or affect their growth rates, and protocols for safe operation of the system will be developed in consultation with radiation health personnel. The advantage of API is that it can spatially map the carbon distribution in soil more accurately than other imaging methods that heavily favor the top layers of soil. The spatial resolution of API will allow the measurement of changes in carbon fraction related to depth and changes associated with plant root architecture and soil porosity. Since repeated measurements are possible over the growing season, the API system will provide a bridge to understanding soil carbon sequestration. If successful, API data will enable the optimization of soil management practices as well as the opportunity to optimize plants for specific traits, such as larger root mass, and deeper roots.
If successful, developments made under the ROOTS program will produce crops that will greatly increase carbon uptake in soil, helping to remove CO2 from the atmosphere, decrease nitrous oxide (N2O) emissions, and improve agricultural productivity.
America’s soils are a strategic asset critical to national food and energy security. Improving the quality of soil in America’s cropland will enable increased and more efficient production of feedstocks for food, feed, and fuel.
Increased organic matter in soil will help reduce fertilizer use, increase water productivity, reduce emissions of nitrous oxide, and passively sequester carbon dioxide from the atmosphere.
Healthy soil is foundational to the American economy and global trade. Increasing crop productivity will make American farmers more competitive and contribute to U.S. leadership in an emerging bio-economy.