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Nitrogen Balance Calculation

Source: R/N_balance.R
N_balance.Rd

Calculates the nitrogen balance of a crop considering various soil and environmental factors.

Usage

N_balance(
  expected_yield_tons_ha = 15,
  crop = "Grano tenero FF (granella)",
  ccp = "Spring-summer crop 100-130 days",
  sand = 50,
  clay = 35,
  Ntot = 1.2,
  SOM = 1.2,
  CN = 9.5,
  oxygen_availability = "Normal",
  winter_rain = 160,
  start_spring_rain = 40,
  prev_crop = "Winter cereals straw removal",
  source = "Cattle slurry",
  fertorg_frequency = "every year",
  location = "Plain adjacent to urbanized areas",
  forg_quantity = 100,
  organic_previous_year_N = 0,
  soil_group = NULL,
  distribution_efficiency = NULL,
  soil_seeding = c("traditional", "no-till"),
  greenhouse = FALSE,
  E_to_D = TRUE
)

Arguments

expected_yield_tons_ha

Expected crop yield in tons per hectare.

crop

Name of the crop.

ccp

Crop calendar period (e.g., "Spring-summer crop 100-130 days").

sand

Percentage of sand in the soil.

clay

Percentage of clay in the soil.

Ntot

Total nitrogen content in the soil (%).

SOM

Soil organic matter content (%).

CN

Carbon to nitrogen ratio of the soil.

oxygen_availability

Oxygen availability level in the soil (e.g., "Normal").

winter_rain

Total winter rainfall (mm).

start_spring_rain

Rainfall at the start of spring (mm).

prev_crop

Previous crop grown in the field.

source

Source of organic fertilizer (e.g., "Cattle slurry").

fertorg_frequency

Frequency of organic fertilizer application (e.g., "every year").

location

Location of the field relative to urban areas.

forg_quantity

Quantity of organic fertilizer applied (m3/ha or t/ha, depending on source). Use 0 for no organic application: Forg is set to 0 without calling organic_fertilization().

organic_previous_year_N

Optional. Total N (kg/ha) from organic fertilization applied in the previous year (same source/frequency). If provided, term F (residual N from previous years' organic, DPI section 3.1.6) is included. Default 0.

soil_group

Optional. Soil group (e.g. from calc_soil_group_and_id_rag()) to use DPI efficiency for current-year organic. If set, distribution_efficiency should also be set.

distribution_efficiency

Optional. "efficient", "medium", or "low" (DPI distribution). Used with soil_group for DPI organic N efficiency.

soil_seeding

One of "traditional" (default) or "no-till". If "no-till", DPI 2026 applies a 3 kg/ha reduction to b1 (readily available N).

greenhouse

Logical. If TRUE, 2 kg/ha are added to D (DPI 2026 greenhouse factor). Default FALSE.

E_to_D

Logical. If TRUE (default), negative E (e.g. buried stalks = -40) is added to D as in Fert_Office v1.26 sheet C&D, and E in the output is set to 0. If FALSE, E stays negative and the balance uses calculate_N_fertilization().

Value

A data frame containing the calculated nitrogen balance components (all in kg/ha):

  • A: Total nitrogen demand of the crop (kg/ha).

  • B: Total soil nitrogen supply (sum of b1 and b2) (kg/ha).

  • b1: Readily available mineral nitrogen (DPI B2) (kg/ha).

  • b2: Mineralizable N from soil organic matter (DPI B1) (kg/ha).

  • C1: Nitrogen leaching loss in winter (kg/ha).

  • C2: Nitrogen leaching loss in spring (kg/ha).

  • D: Nitrogen immobilization loss (kg/ha). Includes the abs(E) contribution if E_to_D = TRUE and E < 0, and +2 if greenhouse = TRUE.

  • E: Nitrogen from previous crop residues (kg/ha). If E_to_D = TRUE and the raw value is negative, this column reports 0 (moved to D).

  • F: Nitrogen from previous years' organic fertilization (kg/ha).

  • Forg: Nitrogen from organic fertilizer (current year, efficient N) (kg/ha).

  • G: Natural nitrogen contribution (e.g., from rainfall) (kg/ha).

  • surplus_pluviometrico: Logical flag (DPI 2026 standard sheet, surplus rain).

Details

The nitrogen fertilization requirement (DPI formula) is: N_fert = A - B + C1 + C2 + D - E - F - Forg - G

Examples

N_balance(expected_yield_tons_ha = 15, crop = "Mais trinciato (classe 700)",
          ccp = "Spring-summer crop 100-130 days", sand = 50, clay = 35,
          Ntot = 1.2, SOM = 1.2, CN = 9.5, oxygen_availability = "Normal",
          winter_rain = 160, start_spring_rain = 40,
          prev_crop = "Winter cereals straw removal", source = "Cattle slurry",
          fertorg_frequency = "every year", location = "Plain adjacent to urbanized areas",
          forg_quantity = 100)
#>      A      B    b1    b2 C1    C2       D E F Forg    G surplus_pluviometrico
#> 1 58.5 38.808 29.16 9.648 20 2.916 21.6424 0 0  0.3 13.4                 FALSE