Water use efficiency

Source: R/waterUseEfficiency.R

Calculates plant water use efficiency (WUE), at different temporal scales, from simulation results.

waterUseEfficiency(
  x,
  type = "Plant Ag/E",
  leaves = "average",
  freq = "days",
  draw = TRUE,
  ylim = NULL
)

Arguments

x

An object of class spwb, pwb, growth or fordyn.

type

A string to indicate the scale of WUE calculation. Either:

  • "Leaf iWUE": Leaf intrinsic WUE, i.e. instantaneous ratio between photosynthesis and stomatal conductance (only for simulations with transpirationMode = "Sperry" or transpirationMode = "Sureau" and subdailyResults = TRUE).

  • "Leaf Ci": Leaf intercellular CO2 concentration (only for simulations with transpirationMode = "Sperry" or transpirationMode = "Sureau" and subdailyResults = TRUE).

  • "Plant An/E": Plant (cohort) net photosynthesis over plant transpiration (only for simulations with transpirationMode = "Sperry" or transpirationMode = "Sureau")

  • "Stand An/E": Stand net photosynthesis over stand transpiration (only for simulations with transpirationMode = "Sperry" or transpirationMode = "Sureau")

  • "Plant Ag/E": Plant (cohort) gross photosynthesis over plant transpiration

  • "Stand Ag/E": Stand gross photosynthesis over stand transpiration

leaves

Either "sunlit", "shade" or "average". Refers to the WUE of different leaf types or the average (with weights according to the LAI of sunlit and shade leaves). Only relevant for type = "iWUE".

freq

Frequency of summary statistics (see cut.Date).

draw

A boolean flag to indicate that a plot should be returned.

ylim

Range of values for y.

Value

If draw=TRUE a plot is returned. Otherwise, the function returns a matrix with WUE values, where rows are dates (at the desired temporal scale), and columns are plant cohorts. In the case of type = "Plant Ag/E", type = "Stand Ag/E", type = "Plant An/E" and type = "Stand An/E" values are in gC/L. In the case of type = "Leaf iWUE" values are in micromol of carbon per mmol of water.

Details

Temporal aggregation of WUE values is done differently depending on the value of type. For type = "Plant Ag/E", type = "Stand Ag/E", type = "Plant An/E" and type = "Stand An/E" sums or daily photosynthesis and transpiration are first calculated at the desired temporal scale and the ratio is calculated afterwards. For type = "Leaf iWUE" intrinsic WUE values are first calculated at the daily scale (as averages of instantaneous An/gs ratios weighted by An) and then they are aggregated to the desired scale by calculating weighted averages, where weights are given by daily photosynthesis.

See also

droughtStress

Author

Miquel De Cáceres Ainsa, CREAF