Parameters for calculating biological nitrogen fixation (BNF) by crop
or system type. Contains 17 rows covering pure legumes (grain and
fodder), non-symbiotic fixation crops (rice, sugarcane), and partial
legume systems (mixed swards, meadows, fallow, weeds). Used by
calc_crop_bnf, calc_nonsymbiotic_bnf,
and calc_bnf.
Format
A data frame with 17 rows and 7 columns:
- Name_BNF
Crop or system name (join key from
Names_BNF).- Ndfa
Proportion of nitrogen derived from atmosphere (0-1). NA for non-symbiotic crops (rice, sugarcane).
- NHI
Nitrogen harvest index: fraction of above-ground N in harvested product. NA for fallow/weeds (Anglade method not applicable). Values from Anglade et al. (2015).
- BGN
Below-ground N factor: ratio of total plant N to above-ground N. NA for fallow/weeds.
- kgNha
Non-symbiotic BNF base rate (kg N/ha/yr). Only set for rice (33) and sugarcane (25); NA for other crops (default 5 used by
calc_nonsymbiotic_bnf).- Leguminous_share
Fraction of leguminous species in the crop or system (0-1). Pure legumes = 1, rice/sugarcane = 0, mixed swards = 0.33, weeds = 0.20, etc.
- Source
Literature reference for the parameter values.