List of databases recommended for finding published research about soil science and cover crops.

"The Crop Explorer Web Site features near-real-time global crop condition information based on satellite imagery and weather data. Thematic maps of major crop growing regions depict vegetative vigor, precipitation, temperature, and soil moisture. Time-series charts depict growing season data for specific agro-meteorological zones. Regional crop calendars and crop area maps are also available for selected regions."

Collection of guidelines, tools, and reports related to the use of cover crops from the NRCS Soil Health Division and Plant Materials Program.

One-page factsheets for official U.S. state soils.

"The Official Soil Series Descriptions (OSD) is a national collection of more than 20,000 detailed soil series descriptions, covering the United States, Territories, Commonwealths, and Island Nations served by USDA-NRCS. The descriptions, in a text format, serve as a national standard."

Click on any of the classes listed at this link (aquic, aridic, etc.) for a full description.

Click on any of the temperature regimes listed at this link (pergelic, cyric, etc.) for a full description.

While the Web Soil Survey is the main source of "current, official soil survey information," this resource links to many "historical and supplemental documents."