EPIC – A Crop & Soil Productivity Simulation Model

The Environmental Policy Integrated Climate (EPIC) model is a cropping systems model that was developed to estimate soil productivity as affected by erosion and simulates approximately eighty crops with one crop growth model using unique parameter values for each crop. It can be configured for a wide range of crop rotations and other vegetative systems, tillage systems, and other management strategies. It predicts effects of management decisions on soil, water, nutrient and pesticide movements, and their combined impact on soil loss, water quality, and crop yields for areas with homogeneous soils and management. EPIC model interfaces include: WinEPIC, iEPIC.

APEX – A Watershed & Land Management Simulation Model

The Agricultural Policy / Environmental eXtender (APEX) model was developed to extend EPIC’s capabilities of simulating land management impacts for small-medium watersheds and heterogeneous farms. It can be configured for land management strategies such as irrigation, drainage, furrow diking, buffer strips, terraces, waterways, fertilization, manure management, lagoons, reservoirs, crop rotation and selection, pesticide application, grazing, and tillage. The routing of water, sediment, nutrient, and pesticide capabilities are some of the most comprehensive available in current landscape-scale models and can be simulated between subareas and channel systems within the model. APEX model interfaces: WinAPEX, ArcAPEX

SWAT – A River Basin Simulation Model

Soil and Water Assessment Tool (SWAT) is a river basin, or watershed, scale model developed to quantify and predict the impacts of land management practices on water, sediment, and agricultural chemical yields in large complex watersheds with varying soils, land use, and management conditions over long periods of time. Basins of several thousand square miles can be studied, but must be divided to account for difference in soils, land use, crops, topography, weather, etc. SWAT accepts outputs from APEX as well as measured data and point sources. Watersheds with no monitoring data can be modeled and impacts of changes in management and climate can be generated.

PHYGROW – A Grazing & Range Land Assessment Model

PHYGROW (Phytomass Growth Model) models above-ground herb and shrub growth, forage consumption, and hydrologic processes. It is capable of modeling growth dynamics of many plant species competing for limited resources while modeling grazing by herbivores in competition for forage resources. It is a tool to determine how variations in landscapes, animal populations (composition, demand, and timing), and weather impact carrying capacity, hydrology, and stability of forage production. It is used to analyze variation in stocking decisions across representative landscapes in a region to determine impact of weather variation on stocking rates of mixed animal populations.

FARMSIM – A Farm Income & Nutrition Simulator for Families

FARMSIM is a simulation model used for projecting the probable economic and nutritional impacts of alternative technologies, farming systems, livestock management programs, marketing arrangements, crop mixes, risk management schemes, and environmental remediation programs on a representative crop/livestock farm. This is a complimentary model hosted and supported by the Agricultural and Food Policy Center @ Texas A&M University

The pioneering team of soil, water, plant, and environmental researchers @ Blackland Research & Extension Center and USDA Grassland, Soil, and Water Laboratory in Temple, Texas have been building and applying computer simulation models for over 40 years. They have created a set of comprehensive water hydrology, soil and land management models used world-wide to examine the impacts of changes in technologies and climate on the resilience and sustainability of agriculture and natural resources.

The core team spans three agencies: Texas A&M AgriLife Research, USDA Agricultural Research Service, and USDA Natural Resources Conservation Service. These fundamental models continue to serve as the foundation of the more complex, continuous models operating on spatial scales, ranging from individual fields to river basins. Four state-of-the-art models (EPIC, APEX, SWAT, and PHYGROW) are currently supported at Temple. Although these models are operational and being used worldwide, researchers continue developing and expanding their capabilities.