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| This new report may be of interest:
https://static.ewg.org/reports/2017/mapping_cover_crops/EWG_CoverCro...
Multi-spectral satellite data was used over several periods during the fall of 2015 and the spring of 2016 to detect cover crops in IA, IL and IN. The Normalized Difference Vegetation Index, or NDVI, derived from Landsat 8 satellite imagery, was used to measure the emergence of vegetation on acres classified as corn and soybean fields in the 2015 U.S. Department of Agriculture Cropland Data Layer. EWG modeled multiple cover crop emergence scenarios in fall 2015 and spring 2016, when data were available to account for different cover crop species and planting windows across the three states. Fall imagery was available and analyzed between late September and early December, and spring imagery between late February and the middle of May. NDVI thresholds used to identify cover crop fields were checked against fields in Iowa visited through windshield surveys. Fields of 10 acres or more were included and counted as cover crop fields for the purposes of this report. Fields smaller than 10 acres were excluded. Results in Iowa were also validated using known locations of 2015 cover crop contracts received through the Iowa Department of Land Stewardship, or IDALS, cost-share program. Fields detected on satellite images were compared to these known cover crop locations from the IDALS data at the Public Land Survey System Section level. If a cover crop field was detected on satellite imagery within a section that received cost share in 2015, it was deemed a match. In all, EWG results matched the cost-share data 72 percent of the time (see Figure 1 below).
Edited by jbgruver 3/15/2017 09:45
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Mapping Cover Crops in IA, IL and IN
