APEX(Agricultural Policy/Environmental eXtender) Model: An Emerging Tool for Agricultural Environmental Analyses

Abstract

The agricultural policy/Environmental eXtender (APEX) model was developed by the Blackland Research and Extension Center in Temple, Texas. APEX is a flexible and dynamic tool that is capable of simulating a wide array of management practices, cropping systems, and other land uses across a broad range of agricultural landscapes, including whole farms and small watersheds. The model can be configured for novel land management strategies, such as filter strip impacts on pollutant losses from upslope crop fields, vegetated grassed waterways in combination with filter strip impacts, and land application of manure removed from livestock feedlots or waste storage ponds. The APEX model has continually evolved since its inception, and the process of adaptation and modification will likely continue as use of the model expands for an ever-increasing range of environmental problems and conditions. Several improvements to specific model subroutines have already been initiated, while other potential improvements have been identified that will require future research and code modification efforts.

Development of Novel QAPEX Analysis System Using Open-Source GIS

“…The APEX model was developed to apply the functions of the EPIC model to an entire farm or a small-scale watershed. This model is also equipped with the function of tracking water, sediments, nutrients, and pesticides that exist in various areas, such as complex terrains, watercourse systems, and watershed exits [10,12]. Using this tracking mechanism, the interactions among the surface runoff, return flow, sedimentation and decomposition of deposits, transfer of nutrients, and groundwater flow can be monitored.…”

“…The results of the APEX model are generated through the variable set in PRNT****.DAT files. Furthermore, simulation results can be generated from a subwatershed or an entire watershed according to the day, month, and year; a summary file of a watershed can be obtained [10]. However, the simulation results from the existing APEX model are displayed in the text form, requiring users to perform additional study to visualize the results.…”

“…In the Conservation Effects Assessment Project, a national project run by the Agricultural Research Service of the United States Department of Agriculture, Natural Resources Conservation Service, and Texas A&M AgriLife Research, the Agricultural Policy/Environmental eXtender (APEX) model and SWAT model were used to assess the effect of agricultural NPSs, and the Best Management Practices (BMPs) were applied to analyze conservation effects. Consequently, the findings have been used as national policy data for the United States [10].…”

Analysis of components and applications of major crop models for nutrient management in agricultural land

“…국내의 작물 모형 연구는 주로 기후변화와 같은 환경변화에 따른 작물 수확량 예측 (Shim et al, 2010;Kim et al, 2013;Lim et al, 2015)이나 농업 비점오염원 평가 모델 (Kim et al, 2014 (Baldwin et al, 1973;Barber and Cushman, 1981). 모형은 모의하고자 하는 시스템이 무엇이냐에 따라 구분된다.…”