Resources Menu

Irrigation Water Analysis

DO YOU KNOW THE QUALITY OF YOUR IRRIGATION WATER

Water quality guidelines recommended for irrigation and general on-farm and domestic use have been developed by the Primary Industries and Natural Resource Management Ministerial Counicils.

The guidelines cover several water parameters that should be analysed to ensure your water is suitable for its intended use. At Vintessential, we have packaged the major parameters into a convienient and cost effective Irrigation Water Test Suite. This suite of tests will give you an overview of the qualitiy of your water and identify any issues that may be affecting water quality.

The Irrigation Water Test Suite is only $99 (+GST) and includes analysis of the following parameters:


pH

The acidity or alkalinity of water should be monitored to ensure it is within a certain range to limit corrosion
and fouling of pumping, irrigation and stock watering systems.


Salinity & Electrical Conductivity

High levels of soluble salts in water can result in reduced plant productivity or the elimination of crops and
native vegetation.


Sodium Adsorption Ratio (SAR)

SAR is an assessment of sodicity, which is the presence of a high proportion of sodium ions relative to
other cations. High SAR values in water can affect soil properties by making the soil more dispersible and
erodible, restricting water entry and reducing the ability of the soil to conduct water. These factors limit
leaching so that salt accumulates over long periods of time, giving rise to saline subsoils.


Sodium

As well as the effect of sodium on sodicity, excessive amounts in irrigation water can cause foliar injury,
particularly following sprinkler application.


Calcium, Magnesium & Hardness

The hardness or softness of water is based on the level of dissolved calcium and magnesium salts. Soft
water has a tendency to be corrosive, while hard water can result in clogging, encrustation and scaling of
pumping equipment, pipes and sprinklers. It is therefore recommended that waters be maintained at a
certain hardness level to minimise corrosion and scaling.

 

Iron

Iron is an essential micro-nutrient in soils, however iron dissolved in irrigation water can cause problems
when it precipitates on plant leaves (light-brown spotting) or in irrigation equipment (clogging of drip
systems). As such, there are recommended limits to the concentration of iron in irrigation waters.


Copper

Although copper is essential for healthy plant growth and is an important component of several plant
enzymes, elevated levels of copper in irrigation water may have a direct phytotoxic effect on plants.


Potassium & Potassium Adsorption Ratio (PAR)

Winery wastewaters used for irrigation can have high levels of exchangeable potassium. While potassium
is involved in the translocation of sucrose to the grapes and is important in balancing berry pH, excessive
potassium in berries can lead to higher than desired pH and the formation of potassium bitartrate.
The potassium adsorption ratio (PAR) describes the ratio of K+ to Ca+ and Mg2+. High PAR values in water
with low EC values can affect soil properties by making the soil more dispersible.


WATER QUALITY GUIDELINE VALUES

PARAMETER VALUE COMMENTS
pH

<5

5-6

6-8.5

>8.5

High corrosion potential

Likelihood of corrosion

Recommended range

Increased fouling potential

Electrical Conductivity & Salinity

<65mS/m

65 -130mS/m

130 - 290mS/m

290 - 520mS/m

520 - 810mS/m

>810 mS/m

Very low salinity

Low salinity

Medium salinity

High salinity

Very high salinity

Extreme salinity

Sodium Adsorption Ration (SAR)

2 - 8

 

8 - 18

18 - 46

46 - 102

Limit for extremely sensitive crops

Limit for sensitive crops

Limit for medium sensitive crops

Limit for high sensitive crops

Sodium

<115 mg/L

115 - 230 mg/L

 

230 - 460 mg/L

 

>460 mg/L

Limit for sensitive crops

Limit for moderately sensitive crops

Limit for moderately tolerant crops

Limit for tolerant crops

Hardness

<60 mg/L CaCO3

>350 mg/L CaCO3

Increased corrosion potential

 

Increased fouling potential

Iron

>0.2 mg/L

<5.0 mg/L

Long-term trigger value

Short-term trigger value

Copper

<0.2 mg/L

<5.0 mg/L

Long-term trigger value

Short-term trigger value

Potassium Adsorption Ratio (PAR)

(Risk values are for waters low in EC, typically <65mS/m)

1 - 5

 

5 - 10

10 - 20

20 - 40

Low to medium risk of soil dispersion

Low to high risk

Medium to high risk

High to very high risk


NOTE: The values in the above table are taken from the Australian and New Zealand Guidelines for Fresh and Marine Water
Quality, developed by the Natural Resource Management Ministerial Council (NRMMC) and the Primary Industries Ministerial
Council (PIMC). Values for PAR were obtained from CRC Care.
They should not be used as a sole determination of the suitability of irrigation water. Other factors such as soil characteristics, climate, plant species and irrigation management must also be considered.

Download the Water Irrigation Factsheet as a PDF

Copyright © 2013 Vintessential Laboratories. No part of this publication may be reproduced in any form or by any means without the permission in writing from the copyright owner