AE                      Calculate Agronomic Efficiency (AE)
IE                      Calculate Internal Efficiency (IE)
NBI                     Calculate N Balance Intensity (NBI)
NHI                     Calculate N Harvest Index (NHI)
NP                      Calculate Nitrogen Productivity (NP)
NRE                     Calculate Fertilizer N Recovery Efficiency
                        (NRE)
NRE15                   Calculate Isotope-Based Recovery Efficiency
                        (NRE15)
NUEFC                   Calculate NUE of a Food Chain (NUEFC)
NUETON-package          NUETON: Nitrogen Use Efficiency Toolkit on
                        Numerics
NUEbal                  Calculate NUE Balance
NUEcrop                 Calculate NUE Crop
NUEsoil                 Calculate NUE Soil
NUEyield                Calculate NUE Yield
NUpE                    Calculate N Uptake Efficiency (NUpE)
NUtE                    Calculate N Utilization Efficiency (NUtE)
NdfF                    Calculate N derived from Fertilizer (NdfF)
PE                      Calculate Physiological Efficiency (PE)
PFP                     Calculate Partial Factor Productivity (PFP)
PNB                     Calculate Partial N Balance (PNB)
TNdfF                   Calculate Total N derived from Fertilizer
                        (TNdfF)
VNF                     Calculate Virtual N Factor (VNF)
calculate_nue_batch     Calculate All NUE Indicators (Batch Processing)
ecoNUE                  Calculate Ecological NUE (ecoNUE)
plot_nue_compare        Plot NUE Comparison
sNBI                    Calculate N Balance Index of a System (sNBI)
sNUE                    Calculate NUE of a System (sNUE)
