<ptfkit/vereecken1989.h>¶
#include <ptfkit/vereecken1989.h>
Vereecken et al. soil-moisture retention regressions for Belgian soils.
Source¶
Vereecken, H., Maes, J., Feyen, J., & Darius, P. (1989). Estimating the soil moisture retention characteristic from texture, bulk density, and carbon content. Soil Science, 148(6), 389-403.
DOI: 10.1097/00010694-198912000-00001
Scope¶
Territory: Belgian territory north of the river axis Samber and Meuse
Dataset: 182 horizons from 40 important Belgian soil series, with textures ranging from sand to heavy clay.
vereecken1989_ptf_result¶
typedef struct {
double theta_r;
double theta_s;
double alpha;
double n;
} vereecken1989_ptf_result;
| Field | Description |
|---|---|
theta_r | Residual volumetric soil water content. (cm^3/cm^3) |
theta_s | Saturated volumetric soil water content. (cm^3/cm^3) |
alpha | Shape parameter of the van Genuchten moisture-retention model. (cm^-1) |
n | Shape parameter of the van Genuchten moisture-retention model. (dimensionless) |
vereecken1989_detailed_ptf_result¶
typedef struct {
double theta_r;
double theta_s;
double alpha;
double n;
} vereecken1989_detailed_ptf_result;
| Field | Description |
|---|---|
theta_r | Residual volumetric soil water content. (cm^3/cm^3) |
theta_s | Saturated volumetric soil water content. (cm^3/cm^3) |
alpha | Shape parameter of the van Genuchten moisture-retention model. (cm^-1) |
n | Shape parameter of the van Genuchten moisture-retention model. (dimensionless) |
Functions¶
calc_ptf_vereecken1989¶
Estimate four parameters of the reduced van Genuchten moisture-retention model from broad texture fractions, bulk density, and carbon content.
static inline vereecken1989_ptf_result calc_ptf_vereecken1989(double sand, double clay, double carbon, double bulk_density);
Parameters¶
| Name | Direction | Description |
|---|---|---|
sand | in | Sand content in the 50-2000 micrometre particle-size fraction. (%) |
clay | in | Clay content in the less-than-2-micrometre particle-size fraction. (%) |
carbon | in | Carbon content determined by the Walkley-Black method. (%) |
bulk_density | in | Dry bulk density measured after drying undisturbed 100-cm^3 cores for 24 hours at 105 degrees Celsius. (g/cm^3) |
Returns¶
A vereecken1989_ptf_result value.
Note
Table 7 reports regressions for theta_s, theta_r, log(alpha), and log(n) using broad particle-size fractions, carbon content, and bulk density.
Note
The paper accepts fitted n values below 1 because constraining n above 1 gave poorer descriptions for many of the measured curves.
Warning
The bulk-density maximum is reviewed as 1.730 g/cm^3 because the supplied transcription's 1.230 value is inconsistent with the reported mean.
calc_ptf_vereecken1989_detailed¶
Estimate van Genuchten parameters from nine particle-size fractions and particle-size distribution descriptors.
static inline vereecken1989_detailed_ptf_result calc_ptf_vereecken1989_detailed(double particle_2000_1000, double particle_1000_500, double particle_500_200, double particle_200_100, double particle_100_50, double particle_50_20, double particle_20_10, double particle_10_2, double clay, double geometric_mean_particle_size, double geometric_standard_deviation, double carbon, double bulk_density);
Parameters¶
| Name | Direction | Description |
|---|---|---|
particle_2000_1000 | in | Particle content from 2000 to 1000 micrometres. (%) |
particle_1000_500 | in | Particle content from 1000 to 500 micrometres. (%) |
particle_500_200 | in | Particle content from 500 to 200 micrometres. (%) |
particle_200_100 | in | Particle content from 200 to 100 micrometres. (%) |
particle_100_50 | in | Particle content from 100 to 50 micrometres. (%) |
particle_50_20 | in | Particle content from 50 to 20 micrometres. (%) |
particle_20_10 | in | Particle content from 20 to 10 micrometres. (%) |
particle_10_2 | in | Particle content from 10 to 2 micrometres. (%) |
clay | in | Particle content below 2 micrometres. (%) |
geometric_mean_particle_size | in | Geometrical mean particle size calculated using the method cited by the paper. (cm) |
geometric_standard_deviation | in | Geometrical standard deviation of particle size calculated using the method cited by the paper. (dimensionless) |
carbon | in | Carbon content determined by the Walkley-Black method. (%) |
bulk_density | in | Dry bulk density measured after drying undisturbed 100-cm^3 cores for 24 hours at 105 degrees Celsius. (g/cm^3) |
Returns¶
A vereecken1989_detailed_ptf_result value.
Note
Table 8 reports transformed regressions in original particle-size variables for theta_r, log(alpha), and log(n).
Note
Detailed particle-size information did not substantially improve theta_s; this function therefore retains the broad-texture theta_s regression.
Warning
The detailed log(alpha) formula restores the carbon and bulk-density terms shown in Table 7 but omitted from the supplied Table 8 transcription.
Warning
The bulk-density maximum is reviewed as 1.730 g/cm^3 because the supplied transcription's 1.230 value is inconsistent with the reported mean.