list_available_years

Show available years for each data type

A comprehensive framework for analyzing agricultural nutrient
balances across multiple spatial scales (county, 'HUC8', 'HUC2') with
integration of wastewater treatment plant ('WWTP') effluent loads for both
nitrogen and phosphorus. Supports classification of spatial units as
nutrient sources, sinks, or balanced areas based on agricultural surplus
and deficit calculations. Includes visualization tools, spatial transition
probability analysis, and nutrient flow network mapping. Built-in datasets
include agricultural nutrient balance data from the Nutrient Use Geographic
Information System ('NuGIS'; The Fertilizer Institute and Plant Nutrition
Canada, 1987-2016) <https://nugis.tfi.org/tabular_data/> and U.S. Environmental
Protection Agency ('EPA') wastewater discharge data from the 'ECHO' Discharge
Monitoring Report ('DMR') Loading Tool (2007-2016)
<https://echo.epa.gov/trends/loading-tool/water-pollution-search>. Data
are downloaded on demand from the Open Science Framework ('OSF') repository to
minimize package size while maintaining full functionality. The integrated
'manureshed' framework methodology is described in Akanbi et al. (2025)
<doi:10.1016/j.resconrec.2025.108697>. Designed for
nutrient management planning, environmental analysis, and circular
economy research at watershed/administrative to national scales.
This material is based upon financial support by the National Science Foundation,
EEC Division of Engineering Education and Centers,
NSF Engineering Research Center for Advancing Sustainable and Distributed
Fertilizer Production (CASFER), NSF 20-553 Gen-4 Engineering Research Centers
award 2133576. We thank Dr. Robert D. Sabo (U.S. Environmental Protection Agency)
for his valuable contributions to the conceptual development and review of this work.

Olatunde Akanbi

manureshed

Spatiotemporal Nutrient Balance Analysis Across Agricultural and
Municipal Systems

list_available_years function

<dl><dt>scale</dt>
<dd>Character. Spatial scale (optional)</dd></dl>

Arguments

List Available Built-in Years — list_available_years

<dl>

<dt>scale</dt>
<dd>Character. Spatial scale (optional)</dd>

</dl>

list_available_years: List Available Built-in Years

Description

Usage

Value

Arguments