Development of Management Systems for the Water Erosion Prediction Project (WEPP) Model to Support Hemp Production in the United States

Abstract

WEPP was developed by the USDA Agricultural Research Service (ARS) as a next-generation, process-based, water erosion prediction tool. This model uses seven subprocesses for soil, climate, management, hydrology, plant growth, residue decomposition, and erosion. In working with ARS and software engineers, NRCS developed a custom web-based interface that automatically accesses many of the subprocess inputs into WEPP. The most time-consuming, site-specific, variables input into WEPP are associated crop management systems and equipment operation (tillage, harvest, sprayer, etc.) parameters. The NRCS custom web-based interface accesses crop files and operational files from a cloud-based crop and management operations database, for use by conservation planners, to build management systems for ease of use, and improve assessment speed. These two file types must be created and parameterized for the NRCS WEPP platform. In addition, the Agricultural Act of 2014 (2014 Farm Bill) and Agricultural Improvement Act of 2018 (2018 Farm Bill) created a path for the legal production of Industrial Hemp (Cannabis sativa). <fig><graphic xlink:href=23006_files/23006-07.jpg id=EDC46587-8F1A-4984-8BFB-6A249F892DC7></graphic></fig> A few states began growing this crop immediately under Section 7606 of the 2014 Farm Bill in support of university research. With the passage of the 2018 Farm Bill, and the removal of several key roadblocks for commercial production, industrial hemp cropping has been rapidly expanding across the US. This expansion created the need to model these management systems for conservation planning. Crop files were developed to provide inputs for the most common industrial hemp production systems: grain, fiber, and essential (CBX) oil. Associated harvest operation files, specifically for fiber harvest and manual harvesting, were developed to complete the management inputs. Agronomists, field-level conservationists, scientists, and programmers effectively collaborated through the process with the use of the tools built into an intuitive web-based interface. This paper provides a description of the industrial hemp crop(s) and operatorial inputs used in WEPP, the tools and methods used for initial crop and operation file construction, how industrial hemp management systems were tested prior to publishing, and their performance in key locations across the US.