County-level annual precipitation data were obtained from NOAA The climate at a glance tool. From this tool, EWG downloaded annual rainfall amounts in inches for all 738 counties in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio and Wisconsin. Annual precipitation values were for the calendar year, January through December, for each year from 2001 to 2020. Since precipitation (and soil moisture) can vary widely throughout the year, we chose to look at annual rainfall.
To determine whether annual precipitation for each county increased between 2001 and 2020, we calculated a correlation coefficient, or r value, to see whether precipitation was positively or negatively correlated with year. Correlation coefficients describe the relationship between the two variables: Positive r values close to 1 indicate a strong relationship between year and increasing precipitation, and negative r values close to -1 indicate a strong relationship between year and decreasing precipitation. We found that 683 of the 738 total counties in the Midwest had a positive r value indicating that annual precipitation was positively correlated with year.
Reimbursement, premium subsidy, and indemnified acres and policies data in this analysis are from USDA's Risk Management Service Cause of Loss Historical Data Files and data are also contained in the EWG Crop Insurance Database. To estimate the percentage of total crop premium subsidies that resulted in excess moisture subsidies, EWG also used data from the USDA's Risk Management Service Business Summary data files.
EWG analyzed crop insurance claims, premium subsidies, indemnified acres and indemnified policies between crop years 2001 and 2020 for the 725 counties in the Midwest that received any excess moisture compensation during the 20-year period. We then overlapped these counties with the counties that had increasing precipitation over time from the NOAA data. Although 683 counties had increasing precipitation, only 661 of them also had excess moisture compensation at some point between 2001 and 2020.
From there we calculated whether excess moisture allowances, premium subsidies, acres, or policies increased over time for the 661 counties using the same statistical methods as above. We determined a correlation coefficient, or r-value, to see if these traits were positively or negatively correlated with year. Positive correlation coefficients showed increasing characteristics over time, while negative correlation coefficients showed decreasing characteristics over time.
To calculate the percentage of total crop insurance claims, subsidies, indemnified acres, and indemnified premiums that resulted from excess moisture, we divided excess moisture payments, subsidies, acres, and contracts by the totals in the entire federal crop insurance program. We then used the same correlation coefficient analysis to see which counties had increasing excess moisture payments, subsidies, acres, and policies as a percentage of total payments, subsidies, acres, and policies.
We pulled data from the EWG Conservation database to assess how much cover crop funding each county received from the USDA's Environmental Quality Incentive Program. The data was only for fiscal years 2017 to 2020 because that is the range of data included in our database. We obtained the payment data in response to a public records request we submitted to the USDA.
We added the payments for covered crops by county over the four years to get the total spending for that practice, and then ranked each county from most to least covering crop EQIP spending. For more information on EQIP data, see program description in the EWG database.
