*3.1.7 Fundamental issues with erosion modeling*

The inherent complexity of landscape systems, regional variation, and a lack of data makes distributed erosion models difficult [14]. A novel investigation is imperative for soil erosion prediction due to the fact that, despite the extensive efforts devoted to soil erosion assessment at the plot or catchment level, the quantitative estimation of soil erosion, which is regionally distributed, has not been comprehensively tackled [110]. The basic difficulty with erosion risk models is validation due to a lack of data to compare model projections with actual soil loss [111]. The data sources from which empirical models were constructed limit their application to locales and ecological circumstances [14]. Smith [112] claims that empirical models are particularly useful in a number of situations since they are the only ones that can be utilized when there is little available data. They have the following restrictions, among others; They have several drawbacks, including the following: (1) they are based on statistical analysis of significant factors in the soil erosion process and

produce only approximate and probable results; (2) they are not practical for eventbased prediction of soil loss; (3) they estimate soil erosion on a single slope rather than within catchments; (4) they do not represent the sedimentation process; (5) they are limited to sheet and/or rill erosion; and (6) they merely take changes in soil over time into account.

Physically-based models are typically the most scientifically valid and applicable to a wide range of soils, climatic circumstances, and land use scenarios because they are based on an understanding of the physical processes that produce erosion and are flexible in both input and output [113]. Ganasri and Ramesh [81] expressed agreement on the notion that models based on physical principles necessitate a significant amount of data, much of which is not easily accessible. They further posited that this implies a typical challenge in parameterizing such models.

Conceptual models can depict the qualitative and quantitative effects of changes in land use without needing a significant amount of input data dispersed across a wide variety of locations and times [14]. Conceptual models, such as the agricultural nonpoint source (AGNPS), occupy an intermediate position between empirical and physically-based models. These models serve as a substitute for the mechanical components of the system in question [56].

#### *3.1.8 Soil erosion: risk management*

When surface vegetation is removed or physically disturbed, the soil is more susceptible to erosion. Seasonally extremely dry circumstances raise the danger of erosion, where there is less vegetation due to inadequate crop and pasture growth [34]. Important management techniques that have an impact on the risk of soil erosion:


The greatest risks related to feeding happen in late summer and autumn if the supply of feed and the amount of cover of each year's crop and grass leftovers is decreasing. The majority of the erosion risk is caused by showing practices such as cultivation and burning of stubble. Grazing management is additionally a significant factor, in particular during dry years, especially if there are more than two subsequent dry seasons [115]. The safeguarding of soil from erosion has significantly increased with the implementation of more environmentally friendly land management techniques such as no-till sowing and stubble retention. In order to avoid soil disturbance and maximize residue protection on the soil surface, no-till sowing entails placing the seed in a small opening in the soil [116]. Water-repellent soils increase the danger of soil erosion by causing poor plant germination and limited development of plants. A key tool for preventing soil erosion is the spreading, digging, and spading of clay to cultivate water-repellent soil [117]. These methods of soil alteration are commonly employed in the Southern Mallee, Upper South East, and portions of the Eyre Peninsula, where there are vast expanses of naturally water-repellent soils [118]. The utilization of these methodologies engenders an escalation in the clay concentration of the topsoil, thereby fortifying and safeguarding the soil from erosion [119]. Livestock can be withdrawn from fields using confined feed before the ground covering deteriorates too far. It is a crucial method for stopping erosion during dry seasons, as well as in the late summer and early fall when vegetation is dwindling [120].
