Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 25, 2001
Publication Date: October 25, 2001
Citation: KASPAR, T.C., PARKIN, T.B., CAMBARDELLA, C.A., KARLEN, D.L., TOMER, M.D. SPATIAL AND TEMPORAL VARIABILITY OF SOIL CARBON. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2001. CD-ROM. MADISON, WI. Technical Abstract: Measurements of soil carbon in 0-5 cm layer were made over three years in two fields at one location in both phases of a no-till corn-soybean rotation. Georeferenced soil samples were taken in a 7.62 m grid pattern in the last year and in selected sampling locations in the first two years. A digital elevation model of the two sites was also prepared from elevation data collected with a global positioning system receiver. Elevation, slope, and curvature of the sampling positions were derived from the elevation model. Soil carbon at the grid sampling positions showed a weak spatial correlation up to lags of 40 m. Beyond 40 m spatial correlation was not detectable. The spatial variation of soil carbon at these sites is quite large and seems to be related to landscape position. Soil carbon at the sampling positions was negatively correlated to slope and elevation. Differences in carbon content were detected between years and tended to be higher following the soybean crop in the rotation. We speculate that some of the spatial variation in soil carbon at this location has been caused by the effect of erosion and sedimentation on crop productivity, organic matter translocation, and organic matter decomposition.