Daughtry, Craig (USDA-ARS, Beltsville, MDUSDA-ARS, Hydrology and Remote Sensing Lab, Beltsville, MD, 20705; Phone: 301-504-501; Fax: 5301-504-8931; Email: firstname.lastname@example.org)
C.S.T.Daughtry *, P.C.Doraiswamy, E.R.Hunt, J.E.McMurtrey, J.H.Prueger
Management of crop residues in agricultural fields is an important consideration for reducing soil erosion and increasing soil organic carbon. Current methods of quantifying crop residue cover are inadequate for characterizing residue cover within fields or across large regions. Our objectives were to evaluate several spectral indices for measuring crop residue cover using satellite multispectral and hyperspectral data and to categorize soil tillage intensity in agricultural fields. Landsat Thematic Mapper and EO-1 Hyperion Imaging Spectrometer data were acquired over agricultural fields in central Iowa in May and June 2004. Crop residue cover was measured in corn and soybean fields using line-point transects. Spectral residue indices using Landsat TM bands were weakly related to crop residue cover. With the Hyperion data, crop residue cover was linearly related to the Cellulose Absorption Index (CAI), which is relative depth of cellulose and lignin absorption features near 2100 nm. Three tillage intensity classes, corresponding to intensive, reduced, and conservation tillage, were correctly identified in 66-68% of fields and two classes, corresponding to conventional (intensive + reduced) and conservation tillage, were correctly identified in 80-82% of the fields. Regional surveys of soil management practices that affect soil conservation and soil carbon dynamics are possible using advanced multispectral or hyperspectral imaging systems.