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Phosphorus Export Risk Matrix

The Two-dimensional Phosphorus Export Risk Matrix (PERM) can be used when it is assumed that soil type does not change.

Left to right on the horizontal axis represents an increase in flow connectivity and upwards on the vertical axis is increased fertilizer application and changes in soil management factors.

Five examples are given to show how the risk of phosphorus changes within the matrix. A pilot version of the PERM is available to download.




medium risk medium risk medium-high risk high risk high risk high risk high risk very high risk very high risk very high risk
medium risk medium risk medium risk medium-high risk high risk high risk high risk high risk very high risk very high risk
medium risk medium risk medium risk medium risk medium-high risk high risk high risk high risk high risk very high risk
medium risk medium risk medium risk medium risk medium risk medium-high risk high risk high risk high risk high risk
medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk high risk high risk high risk
low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk high risk high risk
low-medium risk low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk high risk
low risk low risk low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk
very low risk low risk low risk low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk
very low risk very low risk low risk low-medium risk low-medium risk medium risk medium risk medium risk medium risk medium risk


Click on the coloured squares for examples:

High flow-connectivity, high risk due to fertiliser application.

High flow-connectivity, high risk due to fertiliser application.

Low flow-connectivity, low risk due to fertiliser application.

Low flow-connectivity, low risk due to fertiliser application.

Groundwater dominated system with high risk of phosphorus reaching receiving channels.

Groundwater dominated system with high risk of phosphorus reaching receiving channels.

Groundwater dominated system with low-medium risk of phosphorus reaching receiving channels.

Groundwater dominated system with low-medium risk of phosphorus reaching receiving channels.




2D PERM

Click here to download pilot version of the PERM in Excel.

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© C J M Hewett, 2004 © University of Sheffield, University of Newcastle upon Tyne & Lancaster University 2001, 2004 and 2005
Last updated March 2005