Monday, November 13, 2006

Remote Sensing Soil Tillage Intensity.

C. S. T. Daughtry1, P. C. Doraiswamy1, J. H. Prueger2, T. J. Vyn3, and C. J. Bernacchi4. (1) USDA-ARS-Hydrology & Remote Sensing Lab, Bldg. 007, Room 104, 10300 Baltimore Ave, Beltsville, MD 20705, (2) USDA-ARS-National Soil Tilth Lab, Ames, IA 20705, (3) Purdue Univ, 1150 Lilly Hall, 915 W State St, West Lafayette, IN 47907-1150, (4) Illinois State Water Survey, 2204 Griffith Drive, Champaign, IL 61820

Current methods of quantifying crop residue cover are inadequate for characterizing the spatial variability of residue cover and soil tillage intensity across many fields.  Our objectives were to estimate crop residue cover and soil tillage intensity using satellite hyperspectral data.  Hyperion imaging spectrometer data were acquired over agricultural fields in central Iowa in May 2004 and 2005.  Crop residue cover was measured in corn and soybean fields using line-point transects.  Crop residue cover was linearly related to the cellulose absorption index (CAI) with coefficients of determination (r2) of 0.85 in 2004 and 0.69 in 2005.  Three tillage intensity classes, corresponding to intensive (<15% residue cover), reduced (15-30% cover), and conservation (>30% cover) tillage, were correctly identified in 63-68% of fields.  Classification accuracy increased to 68-82% for two classes, corresponding to conventional (intensive + reduced) and conservation tillage.  Inventories of soil tillage intensity by previous crop type were generated for the whole Hyperion scene in each year.  Regional surveys of soil management practices that affect soil conservation and soil C dynamics are possible using advanced multispectral or hyperspectral imaging systems.