soilStrength4 {soilphysics}

Estimation of precompression stress by Lebert and Horn (1991)

Description

It calculates the soil strength through precompression stress using the pedo-transfer function from Lebert and Horn (1991)

Usage

 
soilStrength4(BD=1.55,AC=10,AWC=15,PWP=26,Ks=0.29,
              OM=1.5,C=30,phi=36,texture="Clay>35", pF=1.8)

Arguments

BD

a numeric vector containing the values of soil bulk density, Mg m^{-3}

AC

a numeric vector containing the values of volumetric air capacity at the specified pF, \%

AWC

a numeric vector containing the values of volumetric available water at the specified pF, \%

PWP

a numeric vector containing the values of volumetric non available water capacity (pF > 4.2), \%

Ks

a numeric vector containing the values of saturated hydraulic conductivity, 10^3 cm s^{-1}

OM

a numeric vector containing the values of organic matter, \%

C

a numeric vector containing the values of cohesion at the specified pF, kPa

phi

a numeric vector containing the values of angle of internal friction at the specified pF, degree

texture

the soil texture classification. See details

pF

the '1.8' or '2.5' value pF

Details

The function returns '0' for soil properties values beyond the range for which the function was built. The default for this function is the values given in the application example by Horn and Fleige (2003). In the 'texture' argument, the user must pass the textural classification 'Sand','SandLoam', 'Silt', 'Clay<35' or 'Clay>35'. See examples.

Value

PC

the precompression stress

Author(s)

Renato Paiva de Lima <[e-mail]> Anderson Rodrigo da Silva <[e-mail]>

References

Lebert, M., Horn, R. (1991) A method to predict the mechanical strength of agricultural soils. Soil and Tillage Research, 19: 275-256.

Horn, R., Fleige, H. (2003) A method for assessing the impact of load on mechanical stability and on physical properties of soils. Soil and Tillage Research, 73: 89-99.

See Also

stressTraffic

Examples

soilStrength4(BD=1.55,AC=10,AWC=15,PWP=26,Ks=0.29,OM=1.5,
              C=30,phi=36,texture="Clay>35", pF=1.8) # Exemple from Horn and Fleige (2003), Table 7

# End (not run)