Author
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Daughtry, Craig |
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Doraiswamy, Paul |
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Hunt Jr, Earle |
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Stern, Alan |
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McMurtrey Iii, James |
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Prueger, John |
Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/16/2005 Publication Date: 11/15/2006 Citation: Daughtry, C.S.T., Doraiswamy, P.C., Hunt, E.R., Stern, A.J., McMurtrey, J.E., Prueger, J.H. 2006. Remote sensing crop residue cover and soil tillage intensity. International Journal of Soil and Tillage Research. 91:101-108. Interpretive Summary: Soils can function as either sources or sinks for atmospheric CO2 depending on land use and management. The depletion of soil carbon is accentuated by soil degradation and intensified by soil mismanagement. Adoption of appropriate conservation and restoration practices can build up soil organic carbon by increasing the input of carbon through crop residue and by decreasing carbon loss through soil erosion. 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 the spatial variability of residue cover within fields or across large regions. We measured crop residue cover in corn and soybean fields in central Iowa and evaluated several remote sensing techniques for predicting crop residue cover using satellite data. Spectral residue indices using Landsat TM bands were weakly related to crop residue cover. A hyperspectral index, Cellulose Absorption Index (CAI), was linearly related to crop residue cover. 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 remote sensing systems. Technical Abstract: Management of plant litter or 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 the spatial variability of 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 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. 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. |