Campbell Scientific Sentek TriSCAN® Manual v 1.2a - Manual (Page 49)

TriSCAN Manual Version 1.2a
Copyright © 1991 – 2004 Sentek Pty Ltd All rights reserved Page 42
Appendix 2: Guidelines for Interpretation of Water
Salinity for Irrigation
Table 7. Gui delines for Interpretations of Water Salinity for Irrigation (from Ayars & Westcott)
1 Salinity measure Units Degree of Restriction on Use
None Slight to
Moderate
Severe
EC
w
dSm
-1
< 0.7 0.7 – 3.0 > 3.0
TDS mg L
-1
< 450 450 -2000 > 2000
1
EC
w
means electrical conductivity of the water salinity, reported in deciSiemens per meter at 25°C (dSm
-1
)
or in units millimhos per centimetre (mmho/cm). Both are equivalent. TDS means total dissolved solids,
reported in milligrams per litre (mgL
-1
).
All plants do not respond to salinity in a similar manner; some crops can produce acceptable yields at much
greater soil salinity than others. This is because some are better able to make the needed osmotic
adjustments enabling them to extract more water from a saline soil.