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United States Department of Agriculture

Agricultural Research Service

APEX
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Agricultural Policy/Environmental eXtender

CONTACTS

Jimmy Williams Hydraulic Engineer TAES (254) 774-6124
Avery Meinardus Computer Assistant TAES (254) 774-6110

MODEL OBJECTIVE

To provide a tool for managing whole farms or small watersheds to obtain maximum production efficiency and maintain environmental quality.

MODEL COMPONENTS

  • Subarea--Epic
    • Hydrology
    • Weather
    • Erosion(water and wind)
    • N and P cycling
    • Pesticide fate
    • Soil temperature,
    • Plant growth
    • Tillage
    • Plant environmental control
    • Economics.
  • Routing
    • Overland flow
    • Channels
    • Flood plains
    • Water
    • Sediment
    • Nutrients
    • Pesticides

MODEL OPERATION

  • Farm or watershed may be divided into several (<100)subareas or fields
  • Daily time step - long term simulations (1-4000 yrs)
  • Soil, weather, tillage and crop parameter data supplied with model
  • Soil profile can be divided into thirty layers
  • Homogeneous subareas
  • Weather generation is optional

    MANAGEMENT CAPABILITIES

    Whole farm - - routing allows evaluation of interactions between fields (surface run-on, sediment deposition and degradation, nutrient and pesticide transport, and subsurface flow).

    Examples: terrace systems, grass waterways, strip cropping, buffer strips, crop rotations, fertilizer, irrigation, liming, furrow diking, drainage, waste management (feed yards, dairies with or without lagoons)


  • Last Modified: 5/19/2006