We test APSIM-SWIM's ability to simulate infiltration and interactions
between the soil water balance and grain crop growth using soil hydraulic
properties derived from independent, point measurements. APSIMSWIM is a
continuous soil-crop model that simulates infiltration, surface crusting, and
soil condition in more detail than most other soil-crop models. Runoff, soil
water, and crop growth information measured at sites in southern Queensland
was used to test the model. Parameter values were derived directly from soil
hydraulic properties measured using rainfall simulators, disc permeameters and
ponded rings, and pressure plate apparatus. In general, APSIM-SWIM simulated
infiltration, runoff, soil water and the water balance, and yield as
accurately and reliably as other soil crop models, indicating the model is
suitable for evaluating effects of infiltration and soil-water relations on
crop growth. Increased model detail did not hinder application, instead
improving parameter transferability and utility, but improved methods of
characterising crusting, soil hydraulic conductivity, and macroporosity under
field conditions would improve ease of application, prediction accuracy, and
reliability of the model. Model utility and accuracy would benefit from
improved representation of temporal variation in soil condition, including
effects of tillage and consolidation on soil condition and bypass flow in
cracks.
infiltration, crop models, APSIM, water balance, soil structure.