Winter cover crops, which can include cereal grains, legumes, or brassicas, are planted in the autumn following harvest of summer row crops such as corn and soybeans, and are terminated in the spring, prior to planting of the subsequent summer crop. By providing living vegetated cover on agricultural fields that would otherwise be fallow over the winter season they can scavenge soil nitrogen and prevent its loss to groundwater. Additional environmental benefits can include reduced soil erosion, improved soil structure and infiltration, increased soil health and carbon storage, and reduced runoff. However, careful planning and management is required to successfully integrate cover crops into productive farming systems.

In the Chesapeake Bay region of the Eastern United States, the Maryland Department of Agriculture (MDA) provides farmers with incentive funding to support cover crop adoption, with payment rates structured to promote effective agronomic management. In practice, the on-farm environmental performance of cover crops is variable. Our research out of the Lower Mississippi-Gulf Water Science Center has developed satellite-based analyses to measure cover crop performance on working farms. Living green vegetation reflects brightly in the near-infrared wavelengths, and absorbs light in the red wavelengths, with additional absorption features associated with nitrogen and cellulose content. We use these spectral characteristics to measure aboveground biomass and nitrogen content as well as the fraction of the soil covered by living vegetation. 

Each year we support Maryland cover crop conservation program management with an operational analysis that uses Harmonized Landsat and Sentinel (HLS) time-series satellite imagery to identify cover crop emergence and termination dates and to derive wintertime and springtime performance estimates for more than 25,000 enrolled fields per year. The resulting data have informed adaptive management of the MDA incentive payment structure to promote effective environmental outcomes and have greatly reduced the workload associated with time-intensive field visits by county agents to confirm springtime termination of cover crop fields. 

This project is the result of a decade-long collaboration between the USGS, the United States Department of Agriculture - Agricultural Research Service (USDA-ARS), and MDA to develop operational tools to inform cover crop cost-share program management. The project is supported by the USGS Land Change Science Program within the Core Science Systems Mission Area, by the USDA Conservation Effects Assessment Project (CEAP), and by the MDA. We are also working in partnership with conservation programs in Missouri, Pennsylvania, and Delaware to supply satellite remote sensing tools supporting implementation and monitoring of cover crop incentive programs including cover crop species mixes and grazing systems.

Satellite remote sensing data products, when applied in collaboration with conservation program managers, can provide valuable input to support adaptive management of conservation incentive programs, increase environmental benefits and understanding of management practices, and assist in agricultural conservation management. In short, we are keeping it green!

W. Dean Hively is a research physical scientist at the Lower Mississippi-Gulf Water Science Center and is stationed at the U.S. Department of Agriculture – Agricultural Research Service in Beltsville, MD, where he leads a research team focusing on Understanding Agricultural Conservation Practices. His work focuses on remote sensing techniques for measuring winter cover crop performance and crop residue cover, the use of perennial grass field borders for poultry bedding production, and landscape processes linking agricultural conservation implementation to water quality outcomes.

Brian T. Lamb is also a research physical scientist at the Lower Mississippi-Gulf Water Science Center and is stationed at New York Water Science Center in Coram, NY. His work focuses on the use of short-wave infrared satellite imagery to measure crop residue cover through lignocellul