The diffuse nature of nonpoint source (NPS) pollution as well as that of the effectiveness of best management practices (BMP) to control NPS pollution necessitates BMP evaluation at the field scale. In this study, a web interface was developed for application of the Agricultural Policy Environmental eXtender (APEX) model at the field scale. The interface contains background databases for field location, soil, agricultural management and climate across the contiguous United States. Users can specify properties to run the model for an individual field and compare the results under various land management and conservation practice choices. A case study was conducted to demonstrate the capability of the web interface for simulating various land management scenarios. This tool can help provide on-site information for NPS pollution management related policies and serve as a communication tool among scientists, engineers, and stakeholders.

非点源（NPS）污染的扩散性质以及控制NPS污染的最佳管理方法（BMP）的有效性，需要在现场进行BMP评估。在这项研究中，开发了一个Web界面，以在实地规模上应用农业政策环境扩展程序（APEX）。该界面包含有关美国各地的田间位置，土壤，农业管理和气候的背景数据库。用户可以指定属性以针对单个字段运行模型，并比较各种土地管理和保护实践选择下的结果。进行了案例研究，以演示Web界面模拟各种土地管理方案的功能。