Package net.simplace.sim.components.soil.erosion

Class ErosionFreebairnAPSIM

java.lang.Object

net.simplace.sim.model.FWSimComponent

net.simplace.sim.components.soil.erosion.ErosionFreebairnAPSIM

All Implemented Interfaces:

net.simplace.sim.util.FWSimFieldContainer

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

Predicts soil erosion considering runoff volume and soil cover fraction.

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.
• APSIM v7.1 source code. Last time accessed: Mar-27-2026
• 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.
• 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.

Author:

Murilo Vianna, Gunther Krauss, gk@uni-bonn.de

Component Variables

Content Type	Name	Description	Data Type	Unit	Min Value	Max Value	Default Value
constant	cKfac	Soil erodibility factor	DOUBLE	1	-	-	0.4
constant	cPfac	Supporting practise factor	DOUBLE	1	-	-	1.0
constant	cSlopeLength	Length of plot	DOUBLE	m	0.0	-	-
constant	cSlopePercent	Slope in percent	DOUBLE	%	0.0	100.0	3.0
constant	cSoilBD	Soil bulk density per layer	DOUBLEARRAY	g/cm3	0.0	-	-
input	iCoverFrac	Fraction of surface cover (crop and residue)	DOUBLE	1	0.0	1.0	-
input	iRunoff	Runoff	DOUBLE	mm/d	0.0	200.0	0.0
out	SedmentConc	Sedment concentration [g/L]	DOUBLE	g/l	0.0	-	-
out	SedmentConcBed	Sedment concentration from bed load [g/L]	DOUBLE	g/l	0.0	-	-
out	SedmentConcSusp	Sedment concentration from suspended load [g/L]	DOUBLE	g/l	0.0	-	-
out	SoilLoss	Soil loss [ton/ha/day]	DOUBLE	t/ha	0.0	-	-
out	mmSoilLoss	Soil loss [mm/day]	DOUBLE	mm	0.0	-	-

Nested Class Summary

Nested classes/interfaces inherited from class net.simplace.sim.model.FWSimComponent

net.simplace.sim.model.FWSimComponent.TEST_STATE

Field Summary

Fields inherited from class net.simplace.sim.model.FWSimComponent

iFieldMap, iFrequence, iInputMap, iJexlRule, iMasterComponentGroup, iName, iOrderNumber, isComponentGroup, iSimComponentElement, iSimModel, iVarMap

Constructor Summary

Constructors

Constructor	Description
ErosionFreebairnAPSIM()
ErosionFreebairnAPSIM(String aName, HashMap<String,net.simplace.sim.util.FWSimVariable<?>> aFieldMap, HashMap<String,String> aInputMap, org.jdom2.Element aSimComponentElement, net.simplace.sim.util.FWSimVarMap aVarMap, int aOrderNumber)

Method Summary

Modifier and Type	Method	Description
protected net.simplace.sim.model.FWSimComponent	clone(net.simplace.sim.util.FWSimVarMap aVarMap)
HashMap<String,net.simplace.sim.util.FWSimVariable<?>>	createVariables()
HashMap<String,net.simplace.sim.util.FWSimVariable<?>>	fillTestVariables(int aParamIndex, net.simplace.sim.model.FWSimComponent.TEST_STATE aDefineOrCheck)	called for single component test to check the components algorithm.
protected void	init()
protected void	process()

Methods inherited from class net.simplace.sim.model.FWSimComponent

addVariable, bind, checkCondition, createSimComponent, createSimComponent, createSimComponent, createSimComponent, doProcess, getConstantVariables, getContentType, getCreateFormXML, getDescription, getEditFormXML, getFieldMap, getFrequence, getFrequenceRuleScript, getInputs, getInputVariables, getMasterComponentGroup, getName, getOrderNumber, getOutputVariables, getVariable, getVariableField, getVarMap, initialize, isConditionCheck, isVariableAvailable, performLinks, performLinks, readInputs, removeVariable, reset, runComponentTest, setVariablesDefault, toComponentLinkingXML, toDocXML, toGroupXML, toOutputDefinitionXML, toResourcesDataXML, toResourcesDefinitionXML, toString, toXML, writeVarInfos

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

ErosionFreebairnAPSIM

public ErosionFreebairnAPSIM()

ErosionFreebairnAPSIM

public ErosionFreebairnAPSIM(String aName,
 HashMap<String,net.simplace.sim.util.FWSimVariable<?>> aFieldMap,
 HashMap<String,String> aInputMap,
 org.jdom2.Element aSimComponentElement,
 net.simplace.sim.util.FWSimVarMap aVarMap,
 int aOrderNumber)

Parameters:

aName -

aFieldMap -

aInputMap -

aSimComponentElement -

aVarMap -

aOrderNumber -

Method Details

createVariables

public HashMap<String,net.simplace.sim.util.FWSimVariable<?>> createVariables()

Specified by:

createVariables in interface net.simplace.sim.util.FWSimFieldContainer

Specified by:

createVariables in class net.simplace.sim.model.FWSimComponent

init

protected void init()

Specified by:

init in class net.simplace.sim.model.FWSimComponent

process

protected void process()

Specified by:

process in class net.simplace.sim.model.FWSimComponent

fillTestVariables

public HashMap<String,net.simplace.sim.util.FWSimVariable<?>> fillTestVariables(int aParamIndex,
 net.simplace.sim.model.FWSimComponent.TEST_STATE aDefineOrCheck)

called for single component test to check the components algorithm.

Specified by:

fillTestVariables in class net.simplace.sim.model.FWSimComponent

clone

protected net.simplace.sim.model.FWSimComponent clone(net.simplace.sim.util.FWSimVarMap aVarMap)

Specified by:

clone in class net.simplace.sim.model.FWSimComponent