R/G.R

In mbask/fertplan: Compute Components Of NPK Fertilization Plans

# G -----------------------------------------------------------------------
# Azoto da apporti naturali

# Supply of nitrogen from atmosphere or from nitrogen-fixing bacteria
#
# Yearly availability is estimated to be 20 kg/ha in levelled crops close
# to urban settlements. This figure has to be appropriately adapted
# to each crop through a [0,1] coefficient. Page 25 of 2020 Guidelines.
# Note that the N estimate is given in negative sign (ie a flow into the soil).
#
#
# @param coeff a simple ratio [0,1] to linearly correct the
# estimate, 1 to estimate 20 kg/ha nitrogen, 0 to estimate 0 kg/ha.
#
# @return Estimate of N from atmosphere of from bacteria in kg/ha
# @export
# @importFrom ensurer ensure
# @examples
# # Returns -10 kg/ha
# G_N_from_atmosphere(0.5)
G_N_from_atmosphere <- function(coeff) `: numeric` ({
  ensurer::ensure(coeff, +is_numeric, +is_vector_rates)
  natural_n(coeff)
})



# Potassium (K) --------------------------------------------------------------
# Immobilizzazione

# Loss of Potassium due to immobilization from Limestone content
#
# Supply of Potassium (K2O) in kg per hactare to counteract immobilization due to Clay
#
# @param clay_pc     Clay content in soil in \%
#
# @return Potassium (K2O) to be supplied (positive sign) to soil in kg/ha. This is a
# correction factor that takes into account the unavailable K quantity due to clay content
# @export
# @importFrom ensurer ensure
# @examples
# # Returns 1.72 kg/ha
# G_K_immob_by_clay(40)
G_K_immob_by_clay <- function(clay_pc) `: numeric` ({
  ensurer::ensure(clay_pc, +is_numeric, +is_vector_pc)
  k_immobilization(clay_pc)
})