|Reeves Iii, James|
Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2005
Publication Date: February 1, 2006
Citation: McCarty, G.W., Reeves, J.B. 2006. Comparison of near infrared and mid infrared diffuse reflectance spectroscopy for field scale measurement of soil fertility parameters. Soil Science. 171:94-102. Interpretive Summary: The increasing interest on the quality of crops has increased the need to assess and monitor soils within croplands. Detailed monitoring of trace metals contents is needed in regions under present or former influence of industrial activities as these activities result in a risk of elevated metal in feed and food. Rapid and nondestructive methods such as infrared spectroscopy provide potentially useful alternatives to time-consuming chemical methods. To assess utility of infrared spectroscopy, we compared results obtained using two different regions of the infrared spectrum (near infrared and mid infrared). The soils used were from a diverse collection obtained throughout metal mining region of Tarnowskie Gory (Upper Silesia/Poland). This region contains soils with elevated contents of zinc, lead and cadmium due to both natural soil forming processes and industrial activities. Results obtained using the mid infrared were much better than those using near infrared; they indicate that mid infrared spectroscopy may be useful for accurate measurement of metals in soil. However, careful development of calibrations will be required for these measurements to ensure accurate results.
Technical Abstract: Use of percision agriculture (site specific management) in agricultural landscapes requires data intensive information on the spatial distribution of soil properties across toposequences found in landscapes. The chemical/physical analysis of the large numbers of soil samples needed for accurate spatial information can be so expensive and time consuming as to place limits on what can be done. For example, traditional methods for determining C in soil require either chemical oxidation which generates wastes which need to be disposed of, or combustion units which are relatively expensive to operate and analyses are time intensive. Where there is a need for the rapid analysis of large numbers of samples, near-infrared diffuse reflectance spectroscopy (NIRS) has come to be used. We compared the ability of near infrared (NIR) and mid infrared (MIR) spectroscopy for field-scale acquisition of soil fertility parameters. We found that both NIR and MIR formed good calibrations for organic carbon, total N and soil texture. These studies demonstrate the utility of infrared spectral approaches for generating the spatial data needed to implement precision agriculture technology.