Wind Erosion in Western Queensland Australia

Chapter 4 –Modelling Soil Erodibility Dynamicsmeasures to physical conditions that can be modelled (Table 4.1c) restrict our ability to linkconditions of climate, soil types and disturbance regimes to soil aggregation, crust conditionsand erodibility. This means that few models have been developed to predict temporalvariations in soil erodibility (Hagen, 2004). Furthermore, there is insufficient evidence tosupport or parameterise the temporal model framework presented in this chapter, whichrequires data to define rates of change in erodibility in response to drought, disturbance, andrainfall. To address these deficiencies, research is required in three generalised areas:1) In obtaining evidence to better define and support the physical boundaries of the soilerodibility continuum (Q min to Q max ).2) In quantifying rates of increases in soil erodibility (growth rates) in response todrought and disturbance (of different types and intensities).3) In quantifying precipitation effects on soil surface conditions under a range of surfacepre-treatments (antecedent climate and disturbance regimes), soil types and climate(e.g. solar radiation intensity and evaporation rates).Figure 4.7 illustrates environmental factors and measurement parameters that should beconsidered when designing experimental studies to quantify soil erodibility relationships withenvironmental dynamics. In addressing the research requirements, effort must be placed inconducting research at high temporal resolutions, across a range of soil types, and usingmethods that allow for results to be compared between studies and related to parameters thatcan be incorporated into spatially explicit models. Future research should extend fromcultivated settings to include rangeland environments, which have received significantly lesssoil erodibility research attention over the last decade.Merrill et al. (1997) described three approaches for building our understanding of soilerodibility dynamics. The first involves drawing information from the extensive existingdatabases on soil aggregation dynamics that have been collected in the United States.Secondly, research should continue to make use of passive monitoring of field conditions.This approach has particular application in describing soil erodibility dynamics under‘natural’ field conditions, i.e. independently managed grazing lands. Thirdly, methodsinvolving active manipulation of field conditions should be used to simulate changes in soilsurface conditions. This approach may involve manipulating precipitation (amounts andfrequency), vegetation cover, soil organic matter and disturbance types and intensities and125