A tidy long-format tibble of tabulated Van Genuchten parameters and the derived A values for the Minidisk Infiltrometer (disc radius 2.25 cm), covering 12 USDA texture classes at eight applied suction levels.
Format
A tibble with 96 rows and 5 columns:
- texture
USDA texture class (character, lowercase). One of:
"sand","loamy sand","sandy loam","loam","silt","silt loam","sandy clay loam","clay loam","silty clay loam","sandy clay","silty clay","clay".- suction_cm
Applied suction level (numeric, cm). One of: 0.5, 1, 2, 3, 4, 5, 6, 7.
- n
Van Genuchten shape parameter n (dimensionless, > 1). Constant across suction levels for a given texture class.
- alpha
Van Genuchten scale parameter α (1/cm). Constant across suction levels for a given texture class.
- A
Tabulated A value for a disc radius of 2.25 cm (cm). Used in the Zhang (1997) relationship K(h) = C₁ / A.
Source
Decagon Devices, Inc. (2005). Mini Disk Infiltrometer User's Manual. Data accessed via the infiltrodiscR package.
See also
infiltration_vg_params() to look up parameters by texture and
suction, parameter_A_zhang() to compute A analytically.
Examples
minidisk_vg_params
#> # A tibble: 96 × 5
#> texture suction_cm n alpha A
#> <chr> <dbl> <dbl> <dbl> <dbl>
#> 1 sand 0.5 2.68 0.145 2.84
#> 2 sand 1 2.68 0.145 2.40
#> 3 sand 2 2.68 0.145 1.73
#> 4 sand 3 2.68 0.145 1.24
#> 5 sand 4 2.68 0.145 0.893
#> 6 sand 5 2.68 0.145 0.642
#> 7 sand 6 2.68 0.145 0.461
#> 8 sand 7 2.68 0.145 0.331
#> 9 loamy sand 0.5 2.28 0.124 2.99
#> 10 loamy sand 1 2.28 0.124 2.79
#> # ℹ 86 more rows
# Subset to a single texture class
subset(minidisk_vg_params, texture == "sandy loam")
#> # A tibble: 8 × 5
#> texture suction_cm n alpha A
#> <chr> <dbl> <dbl> <dbl> <dbl>
#> 1 sandy loam 0.5 1.89 0.075 3.88
#> 2 sandy loam 1 1.89 0.075 3.89
#> 3 sandy loam 2 1.89 0.075 3.91
#> 4 sandy loam 3 1.89 0.075 3.93
#> 5 sandy loam 4 1.89 0.075 3.95
#> 6 sandy loam 5 1.89 0.075 3.98
#> 7 sandy loam 6 1.89 0.075 4.00
#> 8 sandy loam 7 1.89 0.075 4.02