The APSIM slurp module provides a user-defined sink for soil water that can be used to fill the role of a crop within a simulated system.

Inputs for the slurp module consist of plant root (root length profile and extraction potential) and canopy (live LAI, dead LAI, extinction coefficients and canopy height) information. There is also a switch to state whether slurp is to calculate its own soil water uptake or receive this information from another APSIM module.

The slurp module can operate in two modes. The first and simplest mode is where the uptake_source is set to ‘APSIM’. In this type of operation slurp is simply a provider of information to other modules in the APSIM system that perform extraction of water and solutes (eg APSwim). In the second mode of operation the uptake_source is set to ‘calc’ and the soil water demand is taken from the soil by SLURP (if adequate reserves exist) and root length is used to partition uptake between layers.