|Schumacher, J - SOUTH DAKOTA STATE UNIV.|
|Schumacher, T - SOUTH DAKOTA STATE UNIV.|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 1998
Publication Date: N/A
Technical Abstract: Soil movement by tillage has been identified as an erosion producing agent that results in soil erosion rates that can exceed the soil loss tolerance level from convex slope positions. Software (VISUAL BASIC) has been developed to model the change in surface elevation due to annual tillage sequences on rolling topography. The model is based on a diffusive constant (k) which is the negative product of tillage depth, bulk density, and a regression constant that describes soil movement based on slope gradients. The constant k effectively describes downslope movement of soil on an annual basis for tillage conducted in alternating or random directions. Units for k are mass per unit width (kg m**-1) which can be converted to depth or mass per unit area by assigning a value for bulk density. Inputs for the model require: elevation or slope gradient for discrete distance segments, k values for individual tillage operations, bulk density at tillage, and simulation time period. Assumptions within the model to describe changes in elevation for individual soil segments include: a constant slope gradient, elevation of the midpoint, and a uniform rate of soil loss or deposition. The model will be demonstrated over a field transect incremented into 1 m by 1 m soil segments for varying number of years, showing changes in surface elevation and landscape configuration plus annual soil erosion or deposition rates at specific landscape positions.