Wind Erosion in Western Queensland Australia

Chapter 4 –Modelling Soil Erodibility Dynamicsframework. To achieve this, quantifying temperature effects on soil erodibility at hightemporal resolutions (e.g. daily sampling) is required to build on data presented in existingstudies (e.g. Bisal and Ferguson, 1968; Anderson and Bisal, 1969; Bullock et al., 2001).Limitation 5. The model does not consider (quantify) the availability of loose erodiblesediment on the soil surface. This means that any crusted soil surface will be assigned aminimum erodibility and the model will not predict that crusted surfaces can erode undersaltation bombardment processes. While saltation bombardment does not affect theimmediate erodibility of a soil, it does affect the dust production potential. This hasimplications for modelling dust emissions in rangeland environments where crusted playasurfaces that are devoid of vegetation can be significant dust emitters.The model limitations can be addressed by pursuing research to quantify climate andmanagement effects on soil crusting, aggregation and erodibility to wind. Modelling soilerodibility in terms of u *t , and integrating soil moisture effects into the soil erodibility modelrequires that we can first predict temporal changes in the soil aggregate size distributions.This would alleviate the issue of soil erodibility predictions being relative to a reference windvelocity, and would mean that the effects of freeze-thaw processes could be considered froma process-driven perspective. The first step required to address the model limitations is toexamine application of the model and determine the effects of the limitations on the modelperformance.4.5 Model ParameterisationEvidence to support the model framework and parameterise the model components is scarce.Simulating temporal changes in the model growth rate parameter is required if the model is toaccurately simulate soil erodibility dynamics. This is not possible with our current level ofunderstanding of soil aggregation and crust dynamics, and would require making broadassumptions about the response of soils to climate variability and land managementpressures. In particular, parameterisation of the model is dependent on a knowledge of howcrust cover, thickness and strength and aggregate size and stability respond to rainfall, solarradiation, evaporation, trampling, and soil properties like texture, organic matter and saltcontent.121