Read gridded soil hydraulic properties from HWSD onto WHEP's grid.

Reads the HWSD (Harmonized World Soil Database) soil map unit attribute table and raster, resolves each map unit's dominant USDA texture class, looks up that class's volumetric field capacity, wilting point and porosity from soil_hydraulic_by_texture (via the hwsd_texture_usda code crosswalk), and aggregates each property to WHEP's 0.5-degree grid by averaging the native HWSD cells inside each 0.5-degree block. These are the per-cell soil hydraulic drivers the ICBM soil-carbon moisture modifier consumes. Soil texture is a static HWSD property: the result has no year column. Cropping to data$cell_polity follows the same regional-crop path as read_soil_ph(); missing cells are gap-filled from the nearest available neighbour when a target grid is supplied.

Usage

read_soil_hydraulic(hwsd_dir = NULL, data = list(), example = FALSE)

Arguments

hwsd_dir: Path to the directory holding hwsd_data.csv and hwsd.bil. Defaults to Sys.getenv("WHEP_HWSD_DIR").
data: Optional named list of pre-loaded inputs: cell_polity (lon, lat, at minimum), used both to crop the HWSD raster and as the gap-filling target grid.
example: If TRUE, return a small fixture instead of reading data. Defaults to FALSE.

Value

A tibble with lon, lat, t_field (volumetric field capacity), t_wilt (volumetric wilting point) and porosity, each a fraction.

Examples

read_soil_hydraulic(example = TRUE)
#> # A tibble: 1 × 5
#>     lon   lat t_field t_wilt porosity
#>   <dbl> <dbl>   <dbl>  <dbl>    <dbl>
#> 1 -0.25 -0.25    0.29   0.14     0.43