c3CanA: Simulates canopy assimilation for C3 canopies
In serbinsh/biocro: Simulation of Energycane and Sugarcane

Description Usage Arguments Details Value Author(s) References Examples

It represents an integration of the photosynthesis function c3photo, canopy evapo/transpiration and the multilayer canopy model sunML.

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  c3CanA(lai, doy, hr, solar, temp, rh, windspeed,
    lat = 40, nlayers = 8, kd = 0.1, heightFactor = 3,
    c3photoControl = list(), lnControl = list())

`lai`	leaf area index.
`doy`	day of the year, (1–365).
`hr`	hour of the day, (0–23).
`solar`	solar radiation (micro mol m-2 s-1).
`temp`	temperature (Celsius).
`rh`	relative humidity (0–1).
`windspeed`	wind speed (m s-1).
`lat`	latitude.
`nlayers`	number of layers in the simulation of the canopy (max allowed is 50).
`kd`	Ligth extinction coefficient for diffuse light.
`heightFactor`	Height Factor. Divide LAI by this number to get the height of a crop.
`c3photoControl`	list that sets the photosynthesis parameters for c3 plants through the c3photoParms function
`lnControl`	list that sets the leaf nitrogen parameters. LeafN: Initial value of leaf nitrogen (g m-2). kpLN: coefficient of decrease in leaf nitrogen during the growing season. The equation is LN = iLeafN * exp(-kLN * TTc). lnFun: controls whether there is a decline in leaf nitrogen with the depth of the canopy. 'none' means no decline, 'linear' means a linear decline controlled by the following two parameters. lnb0: Intercept of the linear decline of leaf nitrogen in the depth of the canopy. lnb1: Slope of the linear decline of leaf nitrogen in the depth of the canopy. The equation is 'vmax = leafN_lay * lnb1 + lnb0'.

The photosynthesis function is modeled after the version in WIMOVAC. This is based on the well known Farquar model.

list

returns a list with several elements

CanopyAssim: hourly canopy assimilation (Mg/ha per hour)

CanopyTrans: hourly canopy transpiration (Mg/ha per hour)

CanopyCond: hourly canopy conductance (units ?)

TranEpen: hourly canopy transpiration according to Penman (Mg ha^{-1} per hour)

TranEpen: hourly canopy transpiration according to Priestly (Mg/ha per hour)

LayMat: hourly by Layer matrix containing details of the calculations by layer (each layer is a row). col1: Direct Irradiance col2: Diffuse Irradiance col3: Leaf area in the sun col4: Leaf area in the shade col5: Transpiration of leaf area in the sun col6: Transpiration of leaf area in the shade col7: Assimilation of leaf area in the sun col8: Assimilation of leaf area in the shade col9: Difference in temperature between the leaf and the air (i.e. TLeaf - TAir) for leaves in sun. col10: Difference in temperature between the leaf and the air (i.e. TLeaf - TAir) for leaves in shade. col11: Stomatal conductance for leaves in the sun col12: Stomatal conductance for leaves in the shade col13: Nitrogen concentration in the leaf (g m^-2) col14: Vmax value as depending on leaf nitrogen

Fernando E. Miguez

Farquhar model site here ~

data(doy124)
tmp <- numeric(24)

for(i in 1:24){
   lai <- doy124[i,1]
   doy <- doy124[i,3]
   hr  <- doy124[i,4]
 solar <- doy124[i,5]
  temp <- doy124[i,6]
    rh <- doy124[i,7]
    ws <- doy124[i,8]

  tmp[i] <- c3CanA(lai,doy,hr,solar,temp,rh,ws)$CanopyAssim

}

plot(c(0:23),tmp,
            type='l',lwd=2,
            xlab='Hour',
            ylab=expression(paste('Canopy assimilation (Mg  ',
            ha^-2,' ',h^-1,')')))