Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2004
Publication Date: 7/27/2005
Citation: Sullivan, D.G., Shaw, I.N., Mask, P.L., Rickman, D., Guertal, E.A., Luvall, I., Wersinger, I.M. 2005. Evaluation of multispectral data for rapid assessment of in situ wheat straw residue cover. Soil Science Society of America Journal. 69:2007-2013.
Interpretive Summary: Increasing interest in conservation tillage practices demands a more efficient method of monitoring crop residue cover. Maintaining crop residues under reduced tillage operations has been shown to improve soil organic matter content, which influences soil water holding capacity, soil carbon, as well as sedimentation and infiltration. Moreover, federal cost-share programs provide incentives for farmers to adopt practices that lead to increases in soil organic matter over time. Current methods of measuring crop residue are time consuming and expensive. Remote sensing could be used to rapidly measure differences in crop residues over large areas. The objective of this study was to determine whether aircraft and handheld remotely sensed data could be used to quantify wheat residue. In March of 2000 and 2001, residue plots (15 m x 15 m) were established in the Coastal Plain and Appalachian Plateau physiographic regions of Alabama. Wheat (Triticum aestivum L.) straw was hand applied at 0, 10, 20, 50, or 80% cover. Remotely sensed data were acquired using the ATLAS airborne multispectral scanner and a handheld GER 1500 hyperspectral radiometer. Results showed that infrared remotely sensed data could detect differences between in wheat straw treatments at both study sites. ATLAS data were most sensitive to differences in cover treatments showing field scale thermal infrared remote sensing may be used to streamline current methods of measuring changes in residue cover with time.
Technical Abstract: Crop residues influence near surface soil organic carbon content (SOC), impact our ability to remotely assess soil properties, and play a role in global carbon budgets. Methods that measure crop residues are laborious, and largely inappropriate for field-scale to regional estimates. The objective of this study was to evaluate high spectral resolution remote sensing (RS) data for rapid quantification of residue cover. In March 2000 and April 2001, residue plots (15 m x 15 m) were established in the Coastal Plain and Appalachian Plateau physiographic regions of Alabama. Treatments consisted of five wheat (Triticum aestivum L.) straw cover rates (0, 10, 20, 50, and 80%) replicated 3 times. Spectral measurements were acquired monthly via a handheld spectroradiometer (350 ' 1050 nm) and per availability via the Airborne Terrestrial Applications Sensor (ATLAS) (400 ' 12,500 nm). Overall, treatment separation was influenced by soil water content and percent total organic carbon of the residue (degree of decomposition). Results showed that atmospherically corrected visible and near-infrared ATLAS data can differentiate between residue coverages. Similar results were obtained with the handheld spectroradiometer, although treatment differentiation was less consistent. Thermal infrared ATLAS imagery best discriminated among residue treatments due to differing heat capacities between soil and residue. Our results from our study suggest airborne thermal infrared imagery can be used for crop residue variability assessment within the Southeastern United States.