17. Utility Functions

17.1. Pedotransfer Functions (PTFs)

Soil bulk density may be derived using one of the two PTFs below, depending on the availability of other data.

Equation 17.1

where:

is the Euler’s number, approximately 2.71828.

is the percentage of soil organic carbon (%).

is the percentage of sand in the soil (%).

is the percentage of clay in the soil (%).
Equation 17.2

where:

is the percentage of soil organic carbon (%).

17.2. pH conversion

Equation 17.3

where:

is the pH determined in KCl solution (unitless).

is the pH determined in water (unitless).

is the pH determined in CaCl2 solution (unitless).

is the pH of the soil solution (unitless).

is the concentration of H+ in the soil solution (mol L–1).