R/fW.Daycent2.R

In SoilR: Models of Soil Organic Matter Decomposition

#' Effects of moisture on decomposition rates according to the DAYCENT model
#' 
#' Calculates the effects of volumetric water content on decomposition rates
#' according to the Daycent/Century models.
#' 
#' 
#' @param W A scalar or vector of volumetric water content in percentage.
#' @param WP A scalar representing the wilting point in percentage.
#' @param FC A scalar representing the field capacity in percentage.
#' @return A data frame with values of relative water content (RWC) and the
#' effects of RWC on decomposition rates (fRWC).
#' @references Del Grosso, S. J., W. J. Parton, A. R. Mosier, E. A. Holland, E.
#' Pendall, D. S. Schimel, and D. S. Ojima (2005), Modeling soil CO2 emissions
#' from ecosystems, Biogeochemistry, 73(1), 71-91.
fW.Daycent2<-structure(
  function 
    (W,      
     WP=0,   
     FC=100  
     )
   {
     RWC=(W-WP)*100/(FC-WP)
     fRWC=5*(0.287+(atan(pi*0.009*(RWC-17.47)))/pi)
     return(data.frame(RWC,fRWC))
    }
   ,
  ex=function(){
     W=10:90
     fW=fW.Daycent2(W,WP=10,FC=90)
     plot(fW,type="l",ylim=c(0,6)) 
     }
)