Package net.simplace.sim.components.experimental.erosion

Class ErosionFreebairnAPSIM

java.lang.Object

net.simplace.sim.model.FWSimComponent

net.simplace.sim.components.experimental.erosion.ErosionFreebairnAPSIM

All Implemented Interfaces:

net.simplace.sim.util.FWSimFieldContainer

public class ErosionFreebairnAPSIM
extends net.simplace.sim.model.FWSimComponent

This SimComponent uses a modified Universal Soil Loss Equation proposed by Freebairn and Wockner (Freebairn & Wockner, 1986) to predict soil erosion considering runoff volume and soil cover fraction. The algorithm follows the same formulations used in the APSIM (Agricultural Production Systems sIMulator) platform, which was adapted from the PERFECT model (Littleboy et al., 1992). The model has the following form:

\[ \begin{eqnarray} SedConc & = & 16.52 - 0.46 \cdot COV + 0.0031 \cdot COV^2 & \text{(COV } \lt 50 \text{%)} \\ SedConc & = & 2.54 - 0.0254 \cdot COV & \text{(COV } \ge 50 \text{%)} \\ A & = & \frac{SedConc \cdot LS \cdot K \cdot P \cdot Q}{10} \end{eqnarray} \]

Where SedConc is the sediment concentration (g/L); A (SoilLoss) is the event soil loss (t/ha); COV is the soil cover (%) (iCoverFrac * 100), LS is the slope length and steepness factor (dimensionless); K (cKfac) is the soil erodibility factor (dimensionless), P (cPfac) is the supporting practice factor (dimensionless), and Q (iRunoff) is the event runoff (mm). The 1/10 in Eq. 3 resolves the unit’s conversion to obtain A in t/ha. The soil cover fraction (iCoverFrac) (0-1) can be calculated by the SimComponent RunoffSurfaceCover, whereas iRunoff (mm) can be obtained by one of the SimComponents which calculates runoff (e.g., RunoffCurveNumberAPSIM). LS is a slope and length factor in USLE approach, which is calculated with the below equations (Presbitero et al., 1995):

\[ \begin{eqnarray} LS & = & (65.41 \cdot S^2 + 4.56 \cdot S + 0.065) \cdot (L/22.1)^m \\ m & = & 0.6 \cdot [1-e^{(-35.835 \cdot S)}] \end{eqnarray} \]

Where S (cSlopePercent) is the slope angle (%), and L (cSlopeLength) is the length of the catchment (m). The soil bulk density (cSoilBD) in g/cm3 of the top layer is used to convert A from Eq. 3 from t/ha to mm (mmSoilLoss):

\[ \begin{eqnarray} mmSoilLoss & = & \frac{[A \cdot (1e^6/1e^8)]}{cSoilBD[0]} \end{eqnarray} \]

References

Freebairn, D.M., Wockner, G.H., 1986. A study of soil erosion on vertisols of the eastern darling downs, Queensland. I effects of surface conditions on soil movement within contour bay catchments. Aust. J. Soil Res. 24, 135–158. https://doi.org/10.1071/SR9860135

APSIM v7.1 source code. Last time accessed: Dec-14-2022. URL: https://github.com/APSIMInitiative/APSIMClassic/blob/83039e54200481899b4566761f47fd61d53b4fdf/Model/SoilErosion/SoilErosion.cs

Littleboy, M., D.M. Silburn, D.M. Freebairn, D.R. Woodruff, G.L. Hammer, and J.K. Leslie. 1992. Impact of soil erosion on production in cropping systems. I. Development and validation of a simulation model. Aust. J. Soil Res. 30, 757-774.

Presbitero, A.L., Escalante, M.C., Rose, C.W., Coughlan, K.J., Ciesiolka, C.A., 1995. Erodibility evaluation and the effect of land management practices on soil erosion from steep slopes in Leyte, the Philippines. Soil Technol. 8, 205–213. https://doi.org/10.1016/0933-3630(95)00020-8

Holzworth, Dean P., Neil I. Huth, Peter G. deVoil, Eric J. Zurcher, Neville I. Herrmann, Greg McLean, Karine Chenu, et al. “APSIM – Evolution towards a New Generation of Agricultural Systems Simulation.” Environmental Modelling & Software 62 (December 2014): 327–350. https://doi.org/10.1016/j.envsoft.2014.07.009