Submitted to: Soil and Water Conservation Society
Publication Type: Abstract only
Publication Acceptance Date: 3/15/2007
Publication Date: 3/21/2007
Citation: Hively, W.D., Lang, M.W., McCarty, G.W., Sadeghi, A.M., Keppler, J. 2007. Remote sensing of cover crop nutrient uptake on Maryland's Eastern Shore [abstract]. 2007 Soil and Water Conservation Society Annual Conference. p. 36. Interpretive Summary:
Technical Abstract: The use of winter cover crops is being promoted throughout Maryland as an effective agricultural best management practice with great promise for reducing nutrient inputs to the Chesapeake Bay. Remote sensing provides a tool for real-time estimation of cover crop productivity and nutrient uptake efficiency under real-world management and landscape conditions. This project used a combination of remote sensing and field sampling to evaluate cover crop performance on farms within the Choptank River watershed, a CEAP Special Emphasis research location on Maryland's Eastern Shore. The Maryland Department of Agriculture provided information on farmer enrollment in cover crop cost share programs, including field location, planting date, species, and planting method. ArcMap was used to digitize field boundaries and sampling locations. Satellite images (SPOT, 10-m resolution) were subsequently analyzed using ENVI, providing estimates of aboveground cover crop biomass on 136 fields. On-farm sampling provided data for calibration of image interpretation and estimation of cover crop nutrient concentrations. Results showed excellent correlation (R2=0.98) between the satellite-derived vegetation index and observed biomass. Planting date, planting method (aerial, drilled, broadcast), cover crop species (wheat, rye, barley), and previous crop (maize, soy) were all significantly correlated with cover crop biomass, which ranged from 0 to 60 lb/acre. Early planted cover crops produced greater biomass, and rye outperformed barley and wheat. Within species the effect of planting method was apparent (drilled outperformed broadcast, and aerial seeded wheat did not perform as well as expected, likely due to dry conditions following seeding). Additional sampling years are necessary to account for effects of climate. The combination of remote sensing, field sampling, and access to farm program documents used by this project proved to be a successful and powerful method for real-time evaluation of cover crop performance on fields subsidized by the cover crop conservation cost share programs, serving to improve understanding of management effects on cover crop performance and to promote the most effective cover cropping techniques.