Assessing the Impact of Satellite Imagery Resolution on Biomass Estimation Accuracy of Cover Crop Mixtures.

Cover crops can provide benefits such as decreased nutrient loss to leaching and runoff, cycling and fixation of nutrients for a subsequent cash crop, and increased soil organic matter percentage. Programs developed by state and government agencies offer cost-share programs to farmers who plant cover crops because of these ecological benefits. Due to the intensive time and monetary costs associated with in-field cover crop biomass measurement for every field, payment programs are largely based on measures of participation rather than performance. However, cover crops only provide significant environmental sustainability benefits when adequate biomass is established. Research has shown that monoculture grass cover crop biomass can be estimated with 30m pixel-size satellite imagery. The present study aims to determine whether satellite imagery can effectively estimate cover crop biomass in fields with diverse species composition, and whether increased resolution and satellite imaging frequency will increase biomass estimation accuracy. This study will compare multiple 1m² biomass samples collected in each of 12 unique cover crop “cocktails” to Greenseeker®, CropCircle®, and satellite (3.5, 10, and 30-m resolution) normalized difference vegetation index (NDVI) measurements. Sites will be selected from actively growing cover crop stands in farmers’ fields throughout Virginia. Soil samples (30-cm) and plant tissue samples will be analyzed for inorganic nitrogen and total carbon and nitrogen, respectively. Multiple linear regression will be used to estimate the relationship between NDVI values and cover crop biomass. First year results are still being analyzed, and will be presented this fall as preliminary findings.