Hanna Instruments HI 38078 User Manual

Page 2

The chemicals contained in this kit may be hazardous if
improperly handled. Read the relevant Health and Safety
Data Sheet before performing this test.

HEALTH AND SAFETY

REFERENCES

Adaptation of the Standard Methods for the Examination
of water and wastewater

, 18

Ed. 1992, APA AWWA

WEF.
P. Sequi, Chimica del suolo, Patron Editore, Ed. 1991

• Calculate the meq/L of Calcium and Magnesium in your

sample as follows:

where mL of sample is equal to:

a) 2.5 mL if the conductivity is < 2.00 mS/cm;
b) 1.0 mL if the conductivity is > 2.00 mS/cm.

• Rinse all labware with demineralized water after each

analysis and shake dry.

SODIUM ESTIMATION
To estimate the sodium content in your irrigation water,

subtract from the conductivity value (in meq/L) the value of
Calcium and Magnesium (in meq/L):

Sodium Estimation (meq/L) =

= Conductivity (meq/L) - [Ca+Mg] (meq/L)

SODIUM ADSORPTION RATIO CALCULATION

SAR is a parameter that evaluates the Sodium Hazard in
relation to Calcium and Magnesium concentration.
The Sodium Adsorption Ratio (SAR) is calculated as:

PERMEABILITY HAZARD TABLE

It is possible to draw general indications about the perme-
ability hazards in relation to EC

and SAR of the irrigation

water tested [from Ayers and Westcot, FAO#29, Rev.1,
Rome, 1985].

Note: EC

is the electrical conductivity of the irrigation water

and can be expressed as mS/cm (or dS/m) @25°C.