Description Usage Arguments Details Value See Also Examples
This is a very simple function which implements the 'bucket' model for soil water content and it calculates a coefficient of plant water stress.
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precipt |
Precipitation (mm). |
evapo |
Evaporation (Mg H2O ha-1 hr-1). |
cws |
current water content (fraction). |
soildepth |
Soil depth, typically 1m. |
fieldc |
Field capacity of the soil (fraction). |
wiltp |
Wilting point of the soil (fraction). |
phi1 |
coefficient which controls the spread of the logistic function. |
phi2 |
coefficient which controls the effect on leaf area expansion. |
wsFun |
option to control which method is used for the water stress function. |
This is a very simple function and the details can be seen in the code.
A list with components:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | ## Looking at the three possible models for the effect of soil moisture on water
## stress
aws <- seq(0,0.4,0.001)
wats.L <- numeric(length(aws)) # linear
wats.Log <- numeric(length(aws)) # logistic
wats.exp <- numeric(length(aws)) # exp
wats.none <- numeric(length(aws)) # none
for(i in 1:length(aws)){
wats.L[i] <- wtrstr(1,1,aws[i],0.5,0.37,0.2,2e-2,4)$wsPhoto
wats.Log[i] <- wtrstr(1,1,aws[i],0.5,0.37,0.2,2e-2,4,wsFun='logistic')$wsPhoto
wats.exp[i] <- wtrstr(1,1,aws[i],0.5,0.37,0.2,2e-2,4, wsFun='exp')$wsPhoto
wats.none[i] <- wtrstr(1,1,aws[i],0.5,0.37,0.2,2e-2,4, wsFun='none')$wsPhoto
}
xyplot(wats.L + wats.Log + wats.exp + wats.none~ aws,
col=c('blue','green','purple','red'),
type = 'l',
xlab='Soil Water',
ylab='Stress Coefficient',
key = list(text=list(c('linear','logistic','exp', 'none')),
col=c('blue','green','purple','red'), lines = TRUE) )
## This function is sensitive to the soil depth parameter
SDepth <- seq(0.05,2,0.05)
wats <- numeric(length(SDepth))
for(i in 1:length(SDepth)){
wats[i] <- wtrstr(1,1,0.3,SDepth[i],0.37,0.2,2e-2,3)$wsPhoto
}
xyplot(wats ~ SDepth, ylab='Water Stress Coef',
xlab='Soil depth')
## Difference between the effect on assimilation and leaf expansion rate
aws <- seq(0,0.4,0.001)
wats.P <- numeric(length(aws))
wats.L <- numeric(length(aws))
for(i in 1:length(aws)){
wats.P[i] <- wtrstr(1,1,aws[i],0.5,0.37,0.2,2e-2,4)$wsPhoto
wats.L[i] <- wtrstr(1,1,aws[i],0.5,0.37,0.2,2e-2,4)$wsSpleaf
}
xyplot(wats.P + wats.L ~ aws,
xlab='Soil Water',
ylab='Stress Coefficient')
## An example for wsRcoef
## The scale parameter makes a big difference
aws <- seq(0.2,0.4,0.001)
wats.1 <- wsRcoef(aw=aws,fieldc=0.37,wiltp=0.2,phi1=1e-2,phi2=1, wsFun='logistic')$wsPhoto
wats.2 <- wsRcoef(aw=aws,fieldc=0.37,wiltp=0.2,phi1=2e-2,phi2=1, wsFun='logistic')$wsPhoto
wats.3 <- wsRcoef(aw=aws,fieldc=0.37,wiltp=0.2,phi1=3e-2,phi2=1, wsFun='logistic')$wsPhoto
xyplot(wats.1 + wats.2 + wats.3 ~ aws,type='l',
col=c('blue','red','green'),
ylab='Water Stress Coef',
xlab='SoilWater Content',
key=list(text=list(c('phi1 = 1e-2','phi1 = 2e-2','phi1 = 3e-2')),
lines=TRUE,col=c('blue','red','green')))
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