SIMULATION OF TILLAGE AND OTHER MANAGEMENT OPERATIONS IN WEPS

Authors: Wagner, Larry; Fox, Jr, Fred

Submitted to: Soil Erosion for 21st Century Symposium
Publication Type: Proceedings
Publication Acceptance Date: 1/3/2001
Publication Date: 1/3/2001
Citation: In: J.C. Ascough II and D.C. Flanagan, Proc. Int. Symp. Soil Erosion Research for the 21st Century, 3-5 January 2001, Honolulu, HI. St. Joseph, MI: pp 625-628.

Interpretive Summary: The WEPS Management submodel attempts to simulate the major processes related to the most prevalent cultural practices used by producers and land managers that influence a site's susceptibility to wind erosion. The range of practices includes primary and secondary tilling, cultivating, planting/ seeding, harvesting, and fertilizing operations, as well as irrigating, burning, and grazing. The processes are simulated via a physical basis if possible, incorporating conservation of mass and energy concepts. Because use of a minimum number of parameters with readily available and/or attainable values was a goal of the submodel design, simplifications were made in representing some processes. Simulation of other processes was constrained simply by a lack of knowledge. However, because of its design, the WEPS Management submodel can be expanded and improved as new knowledge is gained relating to the physical processes affecting the soil surface and dmass, and biomass.

Technical Abstract: The Wind Erosion Prediction System (WEPS) is a process-based, daily time-step, computer model that predicts soil erosion via simulation of the physical processes controlling wind erosion. To do so, WEPS must also adequately describe changes to the soil state and surface conditions on a daily basis. The WEPS Management submodel component attempts to simulate the major effects related to the most prevalent cultural practices used by producers and land managers that influence a site's susceptibility to wind erosion. The range of practices includes primary and secondary tilling, cultivating, planting/seeding, harvesting, and fertilizing operations, as well as irrigating, burning, and grazing. The Management submodel simulates the variety of land management operations by identifying the primary physical processes involved and representing each individual operation as a sequenced set of those processes. They include: 1) mass manipulation (changes in aggreagate size distribution and soil porosity, mixing of soil and residue among soil layers, and soil layer inversion); 2) surface modification (creation or destruction of ridges and/or furrow dikes that form oriented surface roughness, resurfacing residue, clipping standing residue, flattening standing residue, killing live crop biomass, and removing biomass); and 4)soil amendment (fertilizing, planting, and irrigating). Keywords: Soil erosion, Wind erosion, Air quality, Erosion models, WEPS.