#' Biomass Allocation in Two Grass Species Under Different Nitrate Supply
#'
#' @description
#' This dataset examines biomass allocation patterns in plants, specifically
#' the proportional distribution of biomass to different plant organs (stems,
#' leaves, and roots). The data come from an experiment manipulating nitrate
#' supply in fast-growing and slow-growing grass species.
#'
#' The response variables (stem, leaves, roots) are proportions bounded in the
#' (0,1) interval, making them suitable for simplex regression analysis.
#'
#' @docType data
#' @usage data(Biomass)
#'
#' @format A data frame with 500 observations and 13 variables:
#' \describe{
#'   \item{species_name}{Species code (DfH, DfL, HlH, HlL) where:
#'     \itemize{
#'       \item DfH = D. flexuosa (slow-growing), high nitrate
#'       \item DfL = D. flexuosa (slow-growing), low nitrate
#'       \item HlH = H. lanatus (fast-growing), high nitrate
#'       \item HlL = H. lanatus (fast-growing), low nitrate
#'     }
#'   }
#'   \item{species}{Species scientific name (D. flexuosa or H. lanatus)}
#'   \item{trt}{Nitrate treatment level (high or low)}
#'   \item{day}{Experimental day (0 to 49)}
#'   \item{pl_num}{Plant number (individual plant identifier, 6-8 replicates per treatment)}
#'   \item{ldm_mg}{Leaf dry mass (mg)}
#'   \item{sdm_mg}{Stem dry mass (mg)}
#'   \item{rdm_mg}{Root dry mass (mg)}
#'   \item{tdm_mg}{Total dry mass (mg)}
#'   \item{lmf}{Leaf mass fraction - proportion of biomass allocated to leaves (0-1)}
#'   \item{smf}{Stem mass fraction - proportion of biomass allocated to stems (0-1)}
#'   \item{rmf}{Root mass fraction - proportion of biomass allocated to roots (0-1)}
#'   \item{ln_tdm}{Natural log of total dry mass (log-transformed for allometric analysis)}
#' }
#'
#' @source
#' Data originally made available by bobdouma (2019) at
#' \doi{10.5281/zenodo.3234670}, derived from the
#' experiment described in:
#'
#' Poorter, H., van de Vijver, C.A.D.M., Boot, R.G.A. & Lambers, H. (1995)
#' Growth and carbon economy of a fast-growing and a slow-growing grass species
#' as dependent on nitrate supply. \emph{Plant and Soil}, 171, 217-227.
#'
#' Poorter, H. & Sack, L. (2012) Pitfalls and possibilities in the analysis of
#' biomass allocation patterns in plants. \emph{Frontiers in Plant Science},
#' 3, 259.
#'
#' @references
#' When using this data, please cite:
#'
#' bobdouma (2019) \emph{bobdouma/proportions_beta_Dirichlet: v.01}.
#' \doi{10.5281/zenodo.3234670}.
#'
#' Poorter, H. & Sack, L. (2012) Pitfalls and possibilities in the analysis of
#' biomass allocation patterns in plants. \emph{Frontiers in Plant Science},
#' 3, 259. \doi{10.3389/fpls.2012.00259}
#'
#' @keywords datasets
#'
#' @examples
#' # Load the data
#' data(Biomass)
#'
#' # Quick overview
#' head(Biomass)
#' str(Biomass)
#'
#' # Check that proportions sum to 1 (within rounding error)
#' summary(rowSums(Biomass[, c("lmf", "smf", "rmf")]))
#'
#' # Simple plot of root mass fraction by treatment
#' boxplot(rmf ~ trt * species, data = Biomass,
#'         main = "Root Mass Fraction by Species and Nitrate Treatment",
#'         las = 2)
"Biomass"
