Quantifying Erosion and Deposition In Long-Term Tillage Plots Using Ground-Based Laser Scanning.

Erosion resulting from agricultural tillage has been extensively studied, but long-term erosional soil loss and deposition remain difficult to quantify directly. Ground-based lidar can provide extremely detailed digital elevation data which may be useful for quantifying erosional soil loss and deposition. The objective of this study was to apply lidar for comparison of relative differences in surface elevation in adjacent systems under different tillage practices. To examine the effects of tillage on soil erosion and deposition, lidar scans were performed on two long-term (25 yr) tillage tests in the piedmont region of North Carolina. Tillage ranged in intensity from none (no-till) to extreme (moldboard plow plus disk). Tillage treatments were arranged in a randomized complete block design on sandy clay loams typical of the Piedmont. Pre-trial elevation data do not exist for these studies, so determination of erosion and deposition is problematic, as it must be based on estimation of the unknowable pre-trial surface.  Thus, our initial approach was to measure the average elevation of each experimental unit and compare elevations across treatments. An ANOVA was performed to determine significant differences in elevation. Preliminary results indicate that elevation differences due to treatments were detected by lidar.  On-going analyses aim to estimate the relative erosional soil loss and deposition associated with treatments. Ground-based lidar appears to have great potential in quantifying the effects of various tillage practices on soil erosion and deposition.