C_input_crops: Estimate C inputs by crops

In SoilManageR: Calculate Soil Management Indicators for Agricultural Practice Assessment

Estimate C inputs by crops

Description

Calculates the estimated carbon (C) input into the soil system by harvested main crops.

Usage

C_input_crops(
  crop,
  crop_product = NA,
  crop_residue = NA,
  harvest_index = NA,
  variable_harvest_index = NA,
  HI_intercept = NA,
  HI_slope = NA,
  shoot_root_ratio = NA,
  root_exudation_factor = NA,
  Cc_product = 450,
  Cc_residue = 450,
  Cc_root = 450,
  straw.removal = NA,
  fixed_belowground_input = NA,
  fixed_C_input_root = NA,
  return.comment = FALSE
)

Arguments

crop	Crop type. Must match predefined list (see C_input_crops_LUT)
crop_product	(optional) Dry weight of the exported product, i.e. yield. Default value is taken from table (tDM/ha)
crop_residue	(optional) Dry weight of the residues of the main crop (e.g., straw, sugar beet leaves) (tDM/ha)
harvest_index	(optional) Ratio of the product to the total above ground biomass
variable_harvest_index	(optional) Logical value that is TRUE if the variable harvest index assumptions of Fan et al. (2017) are to be applied (TRUE / FALSE)
HI_intercept	(optional) Intercept of the variable harvest index. Values provided by Fan et al. (2017)
HI_slope	(optional) Slope of the variable harvest index. Values provided by Fan et al. (2017) (ha/tDM)
shoot_root_ratio	(optional) Ratio of the total above ground biomass to the root biomass
root_exudation_factor	(optional) Ratio of the root exudated C to the C in the root biomass
Cc_product	(optional) C concentration in the exported product. Default value is 450 (gC/kgDM)
Cc_residue	(optional) C concentration in the residues of the main crop. Default value is 450 (gC/kgDM)
Cc_root	(optional) C concentration in the roots. Default value is 450 (gC/kgDM)
straw.removal	(optional) Logical value that is TRUE if straw is removed at harvest. When NA then SR value from table is take When TRUE SS is 1 When FALSE SS is 0. Default value is NA
fixed_belowground_input	(optional) Logical value that is TRUE if fixed below ground Carbon inputs are to be assumed (e.g. for temporary leys) (TRUE / FALSE)
fixed_C_input_root	(optional) amount of root C that is assumed if fixed_belowground_input is TRUE (kgC/ha)
return.comment	(optional) logical value if comment are returned or not. Default = FALSE (TRUE/FALSE)

Details

The annual C input by crops were estimated based on crop type and crop yield with the allometric functions of \insertCitebolinder2007;textualSoilManageR:

C_{Product} = Product * CC_{Product}

C_{Straw} = {Product}* \frac{1 - HI}{HI} * CC_{Straw}

C_{Root} = \frac{Product}{SRR*HI} * CC_{Root}

C_{Exudates} = C_{Root} * REF

Where C is the C per fraction (in kgC/ha) and CC is the C content of given fraction (kgC/tDM). Prodcuct is the dry matter yield of a crop in tDM/ha, HI is the harvest index (ratio of product total of product and straw), SRR is the ratio of the shoot biomass (product and straw) to the root biomass, and REF is the root exudation factor (i.e., the ratio of the C exudated by the roots to the C in the root biomass). All fractions are multiplied with a crop and fraction specific S-factor that determines the share of the fraction that is returned to the soil.

If not mentioned otherwise parameters were taken from the publications of \insertCitebolinder2007;textualSoilManageR, \insertCitekeel2017;textualSoilManageR or \insertCitewuest2020;textualSoilManageR. Parameters for potatoes and sugar beets were derived from \insertCitebolinder2015;textualSoilManageR For temporary leys we assumed yield-independent annual C_{Root} of 1.5 MgC/ha and a REF of 0.5 \insertCitetaghizadeh-toosi2020SoilManageR. Furthermore, like \insertCitewuest2020;textualSoilManageR, the belowground C input (C_{Root} + C_{Exudates}) of corn maize, silage maize and cereals were fixed to 0.46 MgC/ha, 1.1 MgC/ha and 0.6 MgC/ha respectively, based on the values from \insertCitehirte2018;textualSoilManageR. Additionally, we applied the yield dependent harvest index (HI = Intercept + Product * Slope) proposed by \insertCitefan2017;textualSoilManageR for cereals, faba beans, peas, corn, rapeseed, and soybeans.

Reference yields were derived from the Swiss fertilizer recommendations \insertCiteGRUD2017_ch8;textualSoilManageR.

All default values can be found in the look-up-table C_input_crops_LUT.

Value

a tibble with the following parameters:

• C_input_product: Estimated soil carbon input from product (e.g. damaged patatos) (kgC/ha),

• C_input_straw: Estimated soil carbon input by straw or other residues (kgC/ha),

• C_input_root: Estimated soil carbon input by roots (kgC/ha),

• C_input_exudate: Estimated soil carbon input by roots (kgC/ha),

• C_input_total: Total estimated Soil carbon input, sum of C_input_straw, C_input_root, C_input_exudate (kgC/ha),

• comment (optional): comment on the derived values

References

\insertAllCited

See Also

• C_input() to calculate C inputs for a management_df

• C_input_cover_crops() to calculate C input for cover crops

• CN_input_amendments() to calculate C (and N) inputs for organic amendments

• C_input_crops_LUT() for the look-up-table for crop reference values

Examples

#example without yield information, default yield is assumed
C_input_crops("wheat, winter")

#example with yield information and straw retention
C_input_crops("barley, spring", crop_product = 4.5, straw.removal = FALSE)

#example with more information
C_input_crops("barley, spring", crop_product = 4.5, harvest_index = 0.4,
              shoot_root_ratio = 2.4, root_exudation_factor = 0.5)

#example with variable harvest index
C_input_crops("barley, spring", crop_product = 4.5, variable_harvest_index = TRUE,
              HI_intercept = 0.35, HI_slope = 0.015, shoot_root_ratio = 2.4,
              root_exudation_factor = 0.5)

#example with fixed below ground input
C_input_crops("maize, silage", crop_product = 18.5, 
              fixed_belowground_input = TRUE, fixed_C_input_root = 1500,
              root_exudation_factor = 0.3) 

SoilManageR documentation built on June 8, 2025, 9:36 p.m.