Figure A4.2 Relationship between sodium adsorption ratio (SAR) and electrical conductivity (EC) of soils and likelihood of soil structure breakdown 22.0 26.0 2.0 14.0 16.5 19.5 1.5 10.5 11.0 13.0 1.0 7.0 5.5 6.5 0.5 3.5 of dispersive soils C 0.0 0.0 0 3 6 9 12 15 1:5 L 0.0 c SAR r t 0.0 ESP 0 5 10 15 20 25 30 Soil SAR1:5 or ESP Note: This figure can also be used as a guide to sodicity risk from irrigation with recycled water, assuming an irrigation leaching fraction of 0.25 and an EC of the irrigation water equivalent to the ECe of the surface soil (not EC1:5). Source: adapted from Rengasamy et al (1984), Cass et al (1995), Peverill et al (1999), Stevens et al (2003) The SAR of recycled water in Australia is in the range 2.6–20, averaging 6, with salinity averaging 1.2 dS/m. Applying these data to Figure A4.3 shows that irrigating with recycled water has associated sodium problems, which need to be managed.
Figure A4.2 Relationship between sodium adsorption ratio (SAR) and electrical conductivity (EC) of soils and likelihood of soil structure breakdown 14.0 22.0 26.0 2.0 10.5 16.5 19.5 1.5 7.0 11.0 13.0 1.0 3.5 5.5 6.5 0.5 0.0 0.0 0.0 0.0 of dispersive soils 0 3 6 9 12 15 SAR 1:5 0 5 10 15 20 25 30 Soil SAR1:5 or ESP ESP Note: This figure can also be used as a guide to sodicity risk from irrigation with recycled water, assuming an irrigation leaching fraction of 0.25 and an EC of the irrigation water equivalent to the ECe of the surface soil (not EC1:5). Source: adapted from Rengasamy et al (1984), Cass et al (1995), Peverill et al (1999), Stevens et al (2003) The SAR of recycled water in Australia is in the range 2.6–20, averaging 6, with salinity averaging 1.2 dS/m. Applying these data to Figure A4.3 shows that irrigating with recycled water has associated sodium problems, which need to be managed. C c t r L
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