Supplemental information for "Effectiveness of Cover Crops on Water Pollutant Reduction from Agricultural Areas"

The Supplemental Material provides
additional information that may not have explicitly been referenced in the associated article. These additional data add substance to the discussion and are intended
to add transparency. The dataset is in spreadsheet form and includes U.S.-specific studies reporting total nitrogen, nitrate, total phosphorus, phosphate, and sediment or erosion concentrations or losses from control and cover crop field plot
studies. Where pertinent data were not reported in tabular format, DataThief software
was used. Some aggregation was done on these data to
appropriately bin them into grass, legume, brassica, and mixed categories,
based on the type of cover crop evaluated. Further loss reduction calculations
were done based on reported concentrations or losses from the literature
reviewed in a site-year approach, where possible. Because of this, the resulting
percent loss reductions reported here may be slightly different from those
reported in the original source.

Further, each study was aggregated to a study component
average (e.g., legume treatment, which may have included more than one type of
legume) in an attempt to represent the study findings while reducing the variability
associated with the site-year approach. These data were used to develop a
series of correlations to evaluate trends associated with cover crop use in the
U.S. to support Conservation Practice Standard 340. Data not reported by a
given study were left blank, and calculations based on missing data were
represented with #N/A.