SIW Salinity Appraisal Lab and Sodicity Analysis...

SIW Salinity Appraisal LabandSodicity Analysis Package

27162-88ad/dk 10/04 2ed

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Cat. No. 27162-88

SIW Salinity Appraisal Laband

Sodicity Analysis Package

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AluVer®

AmVer™

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AquaChek™

AquaTrend®

BariVer®

BODTrak™

BoroTrace™

BoroVer®

C. Moore Green™

CA 610™

CalVer®

ChromaVer®

ColorQuik®

CoolTrak®

CuVer®

CyaniVer®

Digesdahl®

DithiVer®

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Dr. H. Tueau™

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EC 310™

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Just Add Water™

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ManVer®

MolyVer®

Mug-O-Meter®

NetSketcher™

NitraVer®

NitriVer®

NTrak®

OASIS™

On Site Analysis.Results You Can Trust

OptiQuant™

OriFlow™

OxyVer™

PathoScreen™

PbEx®

PermaChem®

PhosVer®

Pocket Colorimeter™

Pocket Pal™

Pocket Turbidimeter™

Pond In Pillow™

PourRite®

PrepTab™

ProNetic™

Pump Colorimeter™

QuanTab®

Rapid Liquid™

RapidSilver™

Ratio™

RoVer®

™

Simply Accurate

SINGLET™

SofChek™

SoilSYS™

SP 510™

Spec ™

StablCal®

StannaVer®

SteriChek™

StillVer®

SulfaVer®

Surface Scatter®

TanniVer®

TenSette®

Test ‘N Tube™

TestYES!

TitraStir®

TitraVer®

ToxTrak™

UniVer®

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2

3

Table of Contents

SPECIFICATIONS.....................................................................................................................5

OPERATION ..........................................................................................................................7

SECTION 1 SALINITY AND SODICITY APPRAISAL ...........................................91.1 Introduction to Salt-Affected Soils ................................................................................9

PROCEDURES ....................................................................................................................13

SECTION 2 SOIL SAMPLING.......................................................................................152.1 Sampling Procedure.....................................................................................................152.2 Obtaining Soil Samples ...............................................................................................152.3 Preparing the Soil for Testing ......................................................................................162.4 Making a Saturated Soil Paste .....................................................................................172.5 Summary of Method....................................................................................................18

SECTION 3 PREPARING AND CALIBRATING ELECTRODES .......................193.1 Conductivity Cup Calibration for Soil and Water .......................................................193.2 Cleaning the Conductivity Cup ...................................................................................203.3 Two Point pH Electrode Calibration ..........................................................................213.4 Care of the Hach Platinum Series pH Electrode..........................................................233.5 Cleaning the Electrode.................................................................................................243.6 Sodium Electrode Calibration General Information....................................................253.7 Calibrating the Sodium Electrode for Saturated Paste and Irrigation Water ...............25

SECTION 4 SALINITY AND SAR OF SOIL AND IRRIGATION WATER .....294.1 Estimating Salinity in Soil ...........................................................................................294.2 Estimating SAR in Soil................................................................................................324.3 Obtaining Irrigation Water Samples ............................................................................334.4 Measuring Salinity in Irrigation Water ........................................................................344.5 Measuring SAR in Irrigation Water. ............................................................................36

APPENDIX A THEORY ...................................................................................................37Description of Salt-Affected Soils.....................................................................................37Causes and Effects of Salt-Affected Soils .........................................................................37Analytical Problems...........................................................................................................38Conductivity Measurement Theory ...................................................................................39Definition of Sodium Adsorption Ratio (SAR) .................................................................41pH Theory..........................................................................................................................41Platinum Series pH Electrode Operation Principal ...........................................................42Sodium Electrode Description...........................................................................................43Sodium Electrode Theory ..................................................................................................44

Table of Contents, continued

Response Time .................................................................................................................. 44Interferences ...................................................................................................................... 45Effect of Ionic Strength ..................................................................................................... 45

APPENDIX B DATA ENTRY TABLES ........................................................................ 47Conductivity Cup Calibration Information ....................................................................... 47Sodium Calibration Information ....................................................................................... 48

GENERAL INFORMATION........................................................................................... 49REPLACEMENT PARTS........................................................................................................ 51HOW TO ORDER ................................................................................................................... 53REPAIR SERVICE .................................................................................................................. 54WARRANTY........................................................................................................................... 55

4

SPECIFICATIONS

Specifications subject to change without notice.

The SIW Salinity Appraisal Laboratory is equipped to facilitate the following sample measurements:

Please refer to the manual supplied with the meter or electrode for more specific performance or technical specifications.

This system is intended to be used for estimating Salinity and/or Sodium Adsorption Ratio (SAR) in saturated soil paste or irrigation water. An integral part of the system is the SoilSYS™ Software and a user-supplied computer meeting the specifications stated in the SoilSYS™* Software User’s Guide.

Factors which can be calculated:

• Saturation Percentage

• Salinity of Saturated Extract

• Salinity of Irrigation Water

• Sodium Concentration Estimation of Saturated Extract (Nase meq/L)

• Sodium Adsorption Ratio

Parameter Measurement System Range (Accuracy)

Conductivity sension™5 Meter; Conductivity Cup Measurement System

0.01–50 mS/cm (5.0% of reading)

pH sension™1 meter; Platinum Series pH Electrode

0–14 pH units (0.02 pH)*

* The SoilSYS™ Software calculates an estimated pH of the saturation extract from the paste data. The Salinity and Sodicity method is only valid for alkaline soils with a pH >7.0.

Temperature 5–45 °C (1 °C)

Sodium sension™1 meter; Platinum Series Sodium Electrode

0.02 mg/L to 10 g/L

Sample Mass AccuLab Pocket Pro Balance

150 g (0.1 g)

* SoilSYS is a trademark of Hach Company.

5

SPECIFICATIONS, continued

• Estimated Calcium and Magnesium Content of Saturated Extract ((Ca + Mg)se meq/L)

Additional Software Capabilities:

• Record time

• Record date

• Record sample location

• Record GPS coordinates

• Add information to the report in the form of notes

• Download data to other programs

Computer Requirements (minimum):

• IBM* PC/AT or compatible with a 386SX processor, 16 mHz, or better

• 4 megabytes of RAM

• Hard disk drive with 2 megabytes or more of free space

• 3½ in., 1.44 megabyte floppy disk drive

• VGA graphics with 640 x 480 or higher resolution, 16 or more colors

• Mouse or other pointing device

• Windows** 3.1 or later, Windows 95/NT

* IBM is a registered trademark of International Business Machines Corporation. ** Microsoft and Windows are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries.

6

OPERATION

7

DANGERHandling chemical samples, standards, and reagents can be dangerous. Review the necessary Material Safety Data Sheets and become familiar with all safety procedures before handling any chemicals.

DANGERLa manipulation des échantillons chimiques, étalons et réactifs peut être dangereuse. Lire les Fiches de Données de Sécurité des Produits (FDSP) et se familiariser avec toutes les procédures de sécurité avant de manipuler tous les produits chimiques.

PELIGROLa manipulación de muestras químicas, estándares y reactivos puede ser peligrosa. Revise las fichas de seguridad de materiales y familiarícese con los procedimientos de seguridad antes de manipular productos químicos.

GEFAHRDas Arbeiten mit chemischen Proben, Standards und Reagenzien ist mit Gefahren verbunden. Es wird dem Benutzer dieser Produkte empfohlen, sich vor der Arbeit mit sicheren Verfahrensweisen und dem richtigen Gebrauch der Chemikalien vertraut zu machen und alle entsprechenden Materialsicherheitsdatenblätter aufmerksam zu lesen.

PERIGOA manipulação de amostras, padrões e reagentes químicos pode ser perigosa. Reveja a folha dos dados de segurança do material e familiarize-se com todos os procedimentos de segurança antes de manipular quaisquer produtos químicos.

SECTION 1 SALINITY AND SODICITY APPRAISAL

1.1 Introduction to Salt-Affected SoilsThree types of salt-affected soils are generally recognized. They are: (1) saline, (2) sodic, and (3) saline/sodic. These three soil types are classified (defined) in terms of electrical conductivity (EC), sodium adsorption ratio (SAR), and soil reaction (pH). These chemical properties have historically been determined on an extract obtained by the vacuum filtration of a saturated soil paste prepared with purified water. The water content of the paste expressed as a weight percentage is termed the saturation percentage (SP). The extract is termed the saturation extract (SE).

Dr. James Rhoades of the U.S. Salinity Laboratory, has developed a method to obtain electrical conductivity (ECe), sodium adsorption ratio (SARe), and soil reaction (pHe) without the time, equipment, and work involved in obtaining a saturated paste extract. The procedure involves preparing the saturated paste, then determining the chemical properties using simple electrochemical testing procedures made directly on the saturated paste.

Table 1 lists the components of the basic SIW Salinity Appraisal Lab and Table 2 lists the components of the SIW Sodicity Analysis Package which may be added for sodicity testing. Refer to Figure 1 for an illustration of the complete kit.

Table 1 SIW Salinity Appraisal Lab (shown in Figure 1)

Item NumberItem Description

Catalog Number

1 SoilSYS™ Software Program 49625-00

2 Stainless steel spatula for mixing saturated paste 56164-00

3 Cleaning Brush 690-00

4 Platinum Series Combination pH Electrode with Electrolyte Gel Cartridges and Instruction Manual

51910-00

5 sension™ 1 pH Meter with 4 AA batteries and Instruction Manual

51700-00

6 sension™ 5 Conductivity Meter with 4 AA batteries and Instruction Manual

51800-00

7 Sodium Standard Solution, 1000 mg/L (43.5 mmol) 14749-49

8 Sodium Standard Solution, 100 mg/L (4.35 mmol) 23181-49

9 Sodium Chloride Standard Solution, 175 mmol 23074-49

9

SECTION 1, continued

The components of the two kits enable the user to obtain all necessary values for the final calculation of salinity, sodicity or both parameters in soil (saturated extract basis) or water. The values may then be entered into the SoilSYS™ Software program for final calculations and report generation.

Specific location in kit not shown

Cups for mixing saturated soil paste 22631-74


Lids for Cat. No. 22631-74 cups 22632-47

10 Deionized Water, 500 mL 272-49


SIW Interpretation Manual 24959-89

11 SIW Salinity Appraisal Lab and Sodicity Analysis Package Instruction Manual

27162-88

12 SoilSYS™ Software User’s Guide 49625-88

13 Snap-top Beakers, 4/pkg 25522-00

14 Soil Sieve 46159-00

15 Balance, Acculab, Pocket Pro with 100 g weight

25568-00

16 Conductivity Cup Base 45723-00

17 Conductivity Cups, 2/pkg 45720-00

18 Wash Bottle 620-14

19 pH 7 Buffer Powder Pillows 22270-66

10 pH 10 Powder Pillows 22271-66

21 Clippers for opening Powder Pillows 968-00


Emery Cloth for cleaning Conductivity Cup electrode surfaces 44511-00

Table 2 SIW Sodicity Analysis Package (shown in Figure 1)

Kit Location DescriptionCatalog Number

* Position available for the optional sodium electrode

Sodium Electrode Package with Ammonium Chloride Gel Cartridges and Instruction Manual

51925-00

Table 1 SIW Salinity Appraisal Lab (shown in Figure 1) (continued)

Item NumberItem Description

Catalog Number

10


Figure 1 SIW Salinity and Sodicity Appraisal Lab Packaging Guide

exit

pH mV

READREADenter

setup

cal

review

exitREADREADenter

sal5

setupCEreview

print1

time3

2

TDS6

erase9

recall7 store

8

cal0

cond4

.

5 64321

11

PROCEDURES

13

SECTION 2 SOIL SAMPLING

2.1 Sampling ProcedureRefer to Figure 2 for the necessary steps for your chosen analysis.

Figure 2

2.2 Obtaining Soil SamplesFor meaningful results, it is very important to obtain soil samples that are representative of the area being tested. Obtain the soil sample with a coring tube, soil auger, or shovel. Avoid sampling unrepresentative areas such as old manure piles, lime piles, fence lines, etc. REMEMBER: The test results represent the testing area only as well as the soil sample that is obtained from that area. The most valid information regarding sampling can be obtained from the local extension office, or university or government agricultural department.

SensION 1

To analyze soil samples To analyze irrigation water

Calibrate Meters and Electrodes

SensION 5pH electrode (see Section 3.3)

Sodium electrode (see Section 3.7)

Obtain samples (see Section 2.2) Obtain samples (see Section 4.3)

Prepare soil for testing (see Section 2.3)

Estimate Salinity (see Section 4.1) Estimate Salinity (see Section 4.4)

(optional) (optional)

Estimate SAR (see Section 4.2) Estimate SAR (see Section 4.5)

Note: Electrodes must be conditioned 24 hours before use. (see Section 3.5)

CleanCalibrate

(see Section 3.2)(see Section 3.1)

ConductivityCups

Make saturated soil paste (see Section 2.4)

15


Sample preparation for field measurement consists of removing rocks and debris and homogenizing by crushing, mixing, and sieving. These steps assure that a correct, representative sample is analyzed.

The following method is commonly used to prepare soil samples for subsequent testing. It applies to all classes of soils. The procedure is adapted from the Recommended Chemical Soil Test Procedures for the North Central Region, Bulletin No. 499 (Revised), October, 1980, published by The North Dakota Agricultural Experiment Station, North Dakota State University.

2.3 Preparing the Soil for Testing

1. Break up the large chunks of soil. Avoid contamination from fertilizer dusts or other sources.

Note: The soil sample is normally air-dried when the analysis is performed in a laboratory. When testing in the field, the sample must only be dry enough to be screened through the soil sieve or otherwise thoroughly mixed and free of rocks and other debris.

Note: Prepare the sample carefully to ensure proper volumetric measurement of the sample. See Section 2.2 on page 15.

2. Use a short board or similar device to crush the air-dried soil.

Note: A mortar and pestle may also be used. Take care to avoid grinding rocks.

3. Pass the crushed soil through a 10-mesh (2 mm) soil sieve assembly (Cat. No. 46159-00).

4. Store the soil in a cool, dry place until the analysis is complete. Rinse the spatula with deionized water before stirring each sample.

Note: Store sample for retesting if necessary.

16


2.4 Making a Saturated Soil Paste For Estimating Salinity and Sodicity

1. Half-fill a clean, dry, 120-mL, snap-top container with soil.

Note: A clean disposable cup can be used instead of the snap-top container provided.

Note: A minimum of 50 mL of saturated soil paste is required for testing in the conductivity cup.

Note: Use consistent technique in making the saturated soil paste for reliable results.

2. While stirring with the spatula, add deionized water until the saturation point is reached.

Note: At saturation, the soil will:

a. glisten and reflect light,

b. flow slightly when the container is tipped and jarred,

c. slide freely and cleanly from the spatula (does not apply to soils with high clay content),

d. not collect free water in surface depressions upon standing for 15 minutes. Slight puddling of water may be seen in sandy soil.

3. Test the soil without delay.

17


2.5 Summary of MethodThe endpoint for mixing a saturated soil paste is sufficiently definite for appraisal purposes. Technique variations, such as adding almost all the water to the soil sample before stirring or adding the air-dried soil to a predetermined amount of water, may be used to speed the preparation time. However, soils with very fine or very coarse textures require special handling. In some clay soils, the amount of water that must be added can vary by 10% or more, depending on the rate of water addition and the amount of stirring. The more rapidly water is added in relation to stirring, the lower the saturation percentage may be.

Researchers have discovered the conductivity of the saturation extract may also be used to measure the salinity of peat soils. With air-dried peats, an overnight wetting period is necessary to obtain a definite endpoint for the saturated paste. If the pH of the peat is ≤ 7.0, the SoilSYS™ software will not accurately predict the pH of the extract. Longer wetting periods are also required for very sodic, highly swelling soils.

18

SECTION 3 PREPARING AND CALIBRATING ELECTRODES

3.1 Conductivity Cup Calibration for Soil and WaterNote: Clean the conductivity cup using the procedure in Section 3.2 on

page 20 before proceeding.

Note: Always fill the conductivity cup to the top with the standard, paste, or water sample.

1. Connect the cable of the conductivity cup base to the sension™ 5 meter.

2. Turn the meter on and press the setup key to enter Setup Mode.

Press the up arrow until the Setup number is 6.

3. In Setup #3, set or verify that Automatic Temperature Correction (ATC) is off by pressing the enter key.

4. Press the exit key to exit the setup mode.

5. Press cond 4 to ensure that the meter is in conductivity mode.

6. With the meter in Conductivity Mode, press the cal key once.

7. Press the down arrow key until the current cell constant is displayed in l/cm. Use the numeric key pad and change the value to 1.000. Press enter to accept it.

8. Fill a Conductivity Cup to the top (with a slight positive meniscus) with 100 mg/L Sodium Standard and place the cup into the base. The reading should be in the range of 1–2 mS.

exitREADREADenter

sal5

setupCEreview

print1

time3

2

TDS6

erase9

recall7 store

8

cal0

cond4

.

READenter

enterexit7 8 94 5 61 2 3

(Off)

cond4

cal0

print1

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cal0

cal0

cal0

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19


3.2 Cleaning the Conductivity Cup

1. Use an Emery Cloth (Cat. No. 44511-00) to gently clean the inside surfaces of the electrodes.

2. Wash the cup thoroughly using a laboratory detergent.

3. Rinse the cup well with deionized water.

4. Swab the surfaces of the electrode with isopropyl alcohol.

The cup is now ready to be calibrated before use.

9. Read and record the conductance value.

Note: Because the cell constant has been set to 1.00, the displayed reading is conductance.

Note: Record the conductance value in the table provided in Appendix B.

10. Read the temperature of the standard using a thermometer accurate to 0.5 °C or the pH electrode and sension™1 meter. Record the temperature.

Note: Record the temperature in the table provided in Appendix B.

11. Repeat steps 8 through 10 using a 43.5 mmol Sodium Standard and a 175 mmol Sodium Standard.

The 43.5 mmol standard should read between 8 and 9 mS and the 175 mmol standard should read between 13.5 and 14.5 mS.

12. Enter the following conductivity values into the conductivity cup calibration menu (first column of the edit list) of theSoilSYS™ Software.

Enter 0.526 mS/cm for the 4.35 mmol standard

Enter 4.87 mS/cm for the 43.5 mmol standard

Enter 18.0 mS/cm for the 175 mmol Standard

Note: Units must be changed from mS/cm to mS when taking readings.

or RepeatSteps 8—10

20


3.3 Two Point pH Electrode Calibration

1. Install the Potassium Chloride Electrolyte Gel Cartridge in the Platinum Series pH Electrode. (See Section 1.3.1 in the Platinum Series pH Electrode Manual for assembly instructions.)

2. Prime the electrode by pushing the dispenser button until gel comes out of the reference junction. Use deionized water to rinse the excess gel from the tip and the outlet.

Note: Dispense gel until no air bubbles are emerging and gel is present at the tubing end.

3. Connect the electrode to the sension1 pH/ISE meter.

Note: Ensure that the electrode has been conditioned according to instructions in Section 1.3.2 in the Platinum Series pH Electrode Manual.)

4. Turn on the meter by pressing I/O. Press pH mV until the display shows pH.

5. Press setup. Press the up arrow three times to reach Setup #4. The slope should be 59 ± 3 mV/decade. Press enter to toggle to the number of desired decimal places, then exit to leave setup.

6. In two 50-mL beakers or cups, prepare buffers of 7.00 and 10.0 pH.

7. Press cal. The display will show:

Standard 1?

8. Rinse the electrode in deionized water and blot dry.

exit

pH mV

READREADenter

setup

cal

review

pH meter

sension1

setup cal

FILL LINE

21


9. Place the electrode in pH 7.0 buffer. Press enter. The display shows:

Stabilizing...

Note: Temperature variation causes changes in buffer pH. Hach sension meters correct for these changes during calibration when using buffers of pH 4, 6.86, 7, and 10.

10. When the pH reading stabilizes, the display will show:

Standard 2?

Remove the electrode from the cup. Rinse with deionized water and blot dry.

Note: The meter will select a stable reading using default meter parameters and the specified resolution. To override the default meter parameters, see the meter manual.

11. Place the electrode in the 10.0 pH buffer. Press enter.

12. After the last calibration point has stabilized and the display reads:

Standard 3?

press exit.

Note: For a three-point calibration, repeat steps 10–11 with an additional buffer.

13. The display will show Store? and the slope of the calibration (which should be 59±3 mV/decade). Press enter to store the calibration, or exit to leave the calibration mode without storing the values.

14. Remove electrode from the buffer. Rinse with deionized water, followed by a small amount of sample, and blot dry.

15. Place the electrode in the sample. The meter will measure the sample pH.

Note: For other calibrations or more complete operating instructions, refer to the manual for the sension1 or Platinum Series pH Electrode.

16. Record the pH and temperature readings when they stabilize.

READenter

FILL LINE

READenter

READenter

OR

FILL LINE

22


3.4 Care of the Hach Platinum Series pH Electrode

3.4.1 Storing the ElectrodeProper electrode storage depends upon how long the electrode will be stored, how quickly the electrode needs to be used, and the type of sample being measured. Storage affects the reference electrolyte gel, the Ag/AgCl reference element, and the pH-sensing glass bulb.

Intermittent storage: Between uses, store the electrode in solutions of similar ionic strength and pH to the samples of interest. Before measuring a new sample, refresh the reference electrolyte gel by clicking the dispenser until fresh gel emerges. Carefully rinse the electrode to prevent sample contamination.

Overnight storage: Store the electrode in Hach pH Electrode Storage Solution to keep the electrode hydrated. The potassium chloride present in the electrolyte gel will not leach out excessively overnight. Prior to use, click the electrolyte gel dispenser. A dilute gel/storage solution will initially be ejected from the reference junction tube. The reference gel of thicker viscosity will follow. Eliminating the dilute gel/storage solution will guarantee continuity of the reference junction with the sample. Blot the reference junction with a tissue to clearly see that the electrolyte gel, undiluted by the storage solution, is emerging.

Longer-term storage: To store electrodes for longer periods, soak the electrode in storage solution (see Overnight storage, above) and re-establish the gel at the reference junction on a daily basis to keep the electrode ready for use. If the electrode soaks for longer periods without purging the diluted electrolyte, the entire reference electrolyte gel cartridge can become diluted through diffusion. Typically this will not harm the AG/AgCl reference element, but the electrolyte cartridge itself will be ruined. This storage method keeps the electrode ready to use, but requires purging the gel every day.

Shelf storage: For very long term storage, store the electrode dry. To empty the reference half-cell of electrolyte gel, remove and discard the electrolyte cartridge. Use a syringe with a male Luer fitting, but no needle, to inject deionized water through the

23


reference cell to flush out the reference electrolyte gel. Expel the water injected into the reference cell with an air-filled syringe. Wet the cotton-wool ball, located in the vinyl storage cap, with storage solution. Place the cap over the electrode. This will help keep the pH glass membrane hydrated. This procedure allows for the longest storage, but takes more time to store and set up.

3.5 Cleaning the ElectrodeNote: To avoid shortening the life of the bulb, don’t clean the bulb more

frequently than necessary.

A contaminated glass bulb or fouled electrode may cause slow response times. Clean the electrode only after troubleshooting as described in Section 5, Troubleshooting, in the electrode manual, or when the electrode is known to be dirty. Follow the instructions below to clean the electrode according to the type of contaminant present:

General contamination: Immerse the electrode tip in 0.1 N hydrochloric acid followed by immersion in 0.1 N sodium hydroxide and again in 0.1 N hydrochloric acid, each time for two minutes. Rinse with deionized water and soak in deionized water for at least 15 minutes.

Oils and fats: Immerse the electrode tip in Alconox™ or other detergent solution. Use a soft brush or ultrasonic bath if necessary. Avoid scratching the glass bulb.

Organic films: Use an appropriate solvent, such as methanol or acetone.

Note: Keep the cable and connector away from dirt, abrasives, and harsh solvents.

After cleaning, refresh reference half-cells by pumping fresh electrolyte through them. If the electrode has been sitting in a sample for several weeks, the reference gel will become contaminated. In this case, discard the cartridge and replace it with a fresh one.

If these steps fail to improve electrode response, complete the ELECTRODE SERVICE REQUEST QUESTIONNAIRE in the back of the Platinum Series pH electrode manual and contact Technical Support.

24


3.6 Sodium Electrode Calibration General InformationA Hach Platinum Series Sodium Electrode must be used for this procedure. Those calculations in the software that estimate sodium concentration are based on the specific formulation of the Hach Platinum Series Sodium Glass.

At least 24 hours in advance, clean, condition, and set up the sodium electrode as instructed in Using the Electrode in the Sodium Electrode Manual, (Cat. No. 48670-88).

Important Note: Sodium Ionic Strength Adjustor (ISA) must not be used for soil paste measurements. Adding ISA will disrupt the ionic equilibrium in the soil solution, causing inaccurate results.

3.7 Calibrating the Sodium Electrode for Saturated Paste and Irrigation Water

While both the pH and sodium electrodes can be connected to the meter simultaneously, only one can be in a solution at any given time.

Inaccurate readings will result if both electrodes are immersed in the same solution at the same time.

1. Dispense the electrolyte gel until it is visibly oozing from the port in the tip of the electrode (close to the sensing bulb). Refer to the Sodium Electrode Manual for additional electrode priming information.

2. Rinse the electrode with deionized water and blot to dry.

Check the tip of the electrode to ensure no gel is visible on the tip. If gel is still visible, rinse and dry the tip of the electrode again.

3. Connect the probe to the BNC connection on the back of the sension1 meter.

4. Place the clean, dry sodium electrode into a flip-top beaker containing 4.35 mmol Sodium Standard. Do not dispense electrolyte into the standard.

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5. To select the sodium electrode (BNC connector) on the sension™1, press setup.

When the numeral 1 is flashing, press enter until BNC appears.

Press exit to return to the reading mode.

Press pH mV until mV appears.

6. Allow five minutes for the reading to stabilize.

Note: If the reading does not stabilize, repeat steps 1 through 4.

Record the reading (in mV) in the table provided in Appendix B.

7. To select the pH electrode (5-pin connector) on the sension™1, press setup.

When the numeral 1 is flashing, press enter until 5-pin appears.


Press pH mV until pH appears.

8. Place a well-rinsed, calibrated pH electrode in the standard to measure the pH and temperature. Do not dispense electrolyte into the standard.

Note: Make sure that the electrode is connected to the 5-pin connector.

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9. Record the pH value in the table provided in Appendix B.

10. Pour 50 mL of the 4.35 mmol sodium standard into the conductivity cup. Make sure the base connector is connected to the sension™ 5 then set ATC to off (Setup option 6) and the cell constant to 1.000 cm-1 (using the cal key). Record the conductance reading in mS.

Note: Record the conductance reading in the table provided in Appendix B.

11. Repeat steps 4–10 for the 43.5 mmol Na+ Standard Solution (Cat. No. 14749-49). Record the results.


Note: While both the pH and sodium electrodes can be connected to the meter simultaneously, only one can be in a solution at any given time.

12. Repeat steps 4–10 for the 175 mmol Na+ Standard Solution (Cat. No. 23074-49). Record the results.


13. Open the SoilSYS™ software program and enter the sodium calibration. (The sodium calibration is entered from the CAL pull-down menu.)

Note: A result calculated by the SIW Salinity and Sodicity Appraisal software below 0.02 mmol Na+ is in the nonlinear area of the response range. Report these results as less than 0.02 mmol.

RepeatSteps 4—10

RepeatSteps 4—10

27

SECTION 4 SALINITY AND SAR OF SOIL AND IRRIGATION WATER

Method 101124.1 Estimating Salinity in Soil

0–20 dS/m For Measurement in Saturated Soil Paste

While both the pH and sodium electrodes can be connected to the meter simultaneously, only one can be in a solution at any given time.

Inaccurate readings will result if both electrodes are immersed in the same solution at once.

1. Connect the cable of the conductivity cup base to the sension™ 5 meter and turn the meter on.

2. Tare the balance with the previously calibrated conductivity cup.

3. Fill the clean and calibrated conductivity cup with prepared saturated soil paste.

Reserve any remaining paste for pH and temperature testing.

4. Tap the bottom of the conductivity cup on a hard surface to dislodge any bubbles in the paste.

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5. Strike off the excess paste with a spatula.

6. Weigh the conductivity cup containing the soil paste.

7. Record the sample weight in the table provided in Appendix B.

8. Place the conductivity cup in the base.

Note: Make sure ATC (Setup option 6) is set to off and the cell constant is set to 1.000 cm -1 (using the CAL key.)

9. Allow the reading to stabilize. Record the reading in mS.

Record the conductivity or store the reading in the meter’s memory using the data logging feature on the sension5 . Refer to the sension™5 Meter Manual for more information.

10. Remove the conductivity cup from the base.

Note: Some sample may be displaced when the pH reading is taken in step 12. Minimize cleanup by removing the cup from the base and from the kit before performing the pH measurement.

11. Rinse the tip of the pH electrode with deionized water to remove excess electrolyte gel from the reference outlet. Blot dry.

12. To select the 5-pin connector (pH electrode) on the sension™1, press setup.



Note: Press pH mV until pH appears.

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13. Record the pH and temperature of the sample in the table provided in Appendix B.

Note: The pH output of the software only applies to alkaline soils with a pH >7.0.

14. Enter the appropriate values into the SoilSYS™ software for an estimation of salinity in the sample.

15. Retain the sample and continue with Section 4.2 on page 32 if an estimation for SAR is also needed.

Stop here if only Salinity estimation is

needed. Continue for

SAR.

31


Method 101134.2 Estimating SAR in Soil

16. To select the BNC connector (sodium electrode) on the sension™1, press setup.



17. Rinse any excess gel from the reference outlet of the calibrated sodium electrode.

Note: See Section 3.7 on page 25 for Sodium Calibration information.

18. Press pH mV until mV appears.

19. Place the calibrated sodium electrode into the sample.

Note: Do not dispense electrolyte into the sample.

Note: Minimize cleanup by removing the cup from the base and the kit before performing the sodium measurement.

20. Allow 2–5 minutes for the reading to stabilize. Record the stable mV reading in the table provided in Appendix B.

Note: If the reading is unstable or erratic, remove the electrode from the sample, dispense more gel and repeat steps 17–19.

21. Enter all appropriate values into the SoilSYS software for an estimation of SAR in soil.

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4.3 Obtaining Irrigation Water SamplesThe minimum volume of water recommended for analysis is approximately 1 liter. Take care to obtain a representative sample. Satisfactory samples of some waters can be obtained only by mixing several portions collected at different times. Collection and mixing techniques depend on local conditions. Refer to the following hints to obtain representative water samples:

• Collect samples from wells only after allowing the pump to run for 10 minutes.

• Take stream samples from moving water.

• Obtain the most valid information regarding sampling from the local government agency which controls water sampling and testing.

• In general, the shorter the elapsed time between collection and analysis of a sample, the more reliable the analytical data. Changes resulting from chemical and biological activity may alter the composition of the sample.

Use the following procedure to obtain an irrigation or drainage water sample:

1. Rinse the sample container a minimum of three times with the water to be analyzed.

2. Fill the container completely full with the water to be analyzed and cap tightly. Do not trap air in the container.

3. Analyze the sample as soon as possible.

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Method 101144.4 Measuring Salinity in Irrigation Water

1. Connect the cable of the conductivity cup base to the sension™ 5 meter. Make sure automatic temperature compensation is set to off. (Setup #6)

Any residue remaining on the conductivity cup electrodes will affect successive readings taken in the cup. Make sure no residue remains in the cup before taking the next reading.

2. Fill the clean, dry, and calibrated conductivity cup with the water sample. The cup must be filled to the top (with a very slight positive meniscus) to ensure proper readings.

Note: The volume of the cup is approximately 50 mL. Determine the exact volume of your cup as follows:

a. Tare an analytical balance with the cup.

b. Fill the cup with deionized water (as described above).

c. Weigh the cup.

d. 1 g = 1 mL at 25 °C

3. Place the filled conductivity cup into the base.

4. Allow the reading to stabilize.

Record the conductance reading or store the reading in the meter’s memory using the meter’s data logging feature. Refer to the sension™ 5 Meter Manual for more information.

Note: Use the data table in Appendix B to record the mS reading.

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5. Remove the cup from the base.

6. Rinse excess gel from the reference outlet of the calibrated pH electrode.

7. To select the pH electrode (5-pin connector) on the sension™1, press setup.



Press pH mV until pH appears.

8. Place the electrode into the sample.

Note: Do not dispense electrolyte into the sample.

9. Allow the reading to stabilize and record the pH and temperature.

Note: Use the data table in Appendix B to record the pH and temperature readings.

10. Enter the appropriate values into the SoilSYS software for an estimation of salinity in the sample.

11. Retain the sample and continue with Section 4.5 on page 36 if an estimation for SAR is also needed.

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Method 101244.5 Measuring SAR in Irrigation Water.

12. To select the sodium electrode (BNC connector), press setup.



13. Rinse any excess gel from the reference outlet of the calibrated sodium electrode.

Note: See Section 3.6 on page 19 for Sodium Calibration information.

14. Press pH mV until mV appears.

15. Place the sodium electrode into the sample.

Note: Do not place both electrodes in the same sample at once.

16. Allow 2-5 minutes for the reading to stabilize. Record the stable mV reading in the data table in Appendix B.

Note: If the reading is unstable or erratic, remove the electrode from the sample, dispense more electrolyte gel, and repeat steps 13–16.

17. Enter all appropriate values into the SoilSYS software for an estimation of SAR in irrigation water.

Note: Use the data table in Appendix B to record the readings.

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36

APPENDIX A THEORY

Description of Salt-Affected Soils

Saline Soils — Although salinity does not affect the physical properties of the soil, it can be harmful to plants because high levels of soluble salts affect the osmotic pressure of the soil solution. The increased salt in the soil solution reduces the availability of soil water to plants and creates an environment of artificial drought. In extreme cases, water can actually be drawn out of the plant, resulting in dehydration and death. Saline soils are associated with a soil condition characterized by white crusts of salts on the surface of affected areas. This condition is often called white alkali.

Sodic Soils — Sodic soils refer to those soils in which the sodium adsorption ratio and pH are high enough relative to the conductivity to change the physical conditions of soils. In extreme cases, the affected soil is dispersed and infiltration/percolation of water becomes increasingly slower. This type of soil is often referred to as black alkali, gumbo, or slick spots. Sodic soils frequently occur in semi-arid and arid regions in small irregular areas.

Saline/Sodic Soils — These salt-affected soils contain large amounts of soluble salts and a high sodium adsorption ratio. In appearance and character they are similar to saline soils until the soluble salts are leached out by artificial drainage. At that point the soils sometimes become sodic and the soil is in a poorer condition then before leaching.

Note: Saline soils do not respond to chemical amendments. Only leaching of the salts through adequate drainage reclaims these soils. Saline/sodic and sodic soils do respond to calcium amendments and drainage. In the case of sodium affected soils that contain appreciable amounts of free lime, sulfur can be added as an amendment to reclaim the soil.

Causes and Effects of Salt-Affected SoilsSalt-affected soils usually occur because of the inherent parent material, or due to water transported salts from irrigation, seeps, or high water tables. Because most arable land today is already in cultivation, increases in world food supply come from more intensive use of the available land. This usually means adopting

37

APPENDIX A, continued

irrigation, which allows for greater yields per unit of land, but irrigation water introduces more salts to the soil than can be utilized by the plant. As a result, salt levels tend to increase with irrigation. If proper irrigation management is not observed, or if the irrigation water itself is of poor quality (high salts), then yield reduction and deterioration of soil structure can result.

Analytical ProblemsIn the late 1940s, the U.S. Salinity Laboratory in Riverside, California determined that the most viable method for salinity and sodicity appraisal would be based on the chemical analysis of an aqueous saturation paste extract of the soil sample.

This method of analysis has inherent problems, including the extensive time, labor, and equipment needed for vacuum filtration of the saturated paste. This effectively prevents the quick field salt assessment often needed for on-site management decisions, and is a problem for routine monitoring because laboratory analysis can be slow and expensive.

Prior to the decision favoring the saturated paste extract for evaluating salinity, researchers had considered measuring the resistance of the saturated paste. This method was quick because vacuum filtration was not necessary. However, it was realized that this method needed individual calibrations for differing soil textures. The procedure was discontinued because of the lack of a practical procedure to determine the soil type calibrations. However, recent research conducted by Dr. J.D. Rhoades of the U.S. Salinity Laboratory has resulted in mathematical factors to make calculated corrections for this variability. As a result, it is now possible to evaluate salinity in a saturated paste without vacuum filtration.

This method requires a conductivity/resistance measurement made on a paste with a known saturation percentage. This is made possible using a conductivity/resistance cell which is actually a cup of known volume. The weight of the paste relative to the fixed volume can be used to determine saturation percentage which can then be used to establish the paste conductance/salinity relationship. Based on this data, the saturation percentage and paste conductance, the conductivity of the saturation extract can be inferred.

38


Mathematically the saturation percentage equals:

Mineral-based soils have a mean particle density of close to 2.65 g/cm3 regardless of their texture. Calculate the SP of mineral-based soils from the volume of the paste relative to the weight of the paste.

The procedure requires the following steps:

1. The saturated paste of a soil sample is made and allowed to equilibrate.

2. The prepared paste is then transferred to a salinity cup with a known volume and tare weight.

3. The weight of the paste is assessed, and the temperature and conductance is measured.

4. Using a computer program, saturation percentage and saturation extract conductivity is calculated.

The Hach Conductivity Cup kit is designed to simplify the measurement of conductivity in soil. This simplification is accomplished by allowing the user to measure the conductance of a saturated soil paste instead of a filtered liquid sample.

Conductivity Measurement TheoryThe term conductance refers to the ability of materials to carry an electric current. Liquids which carry an electric current are generally referred to as electrolytic conductors. The flow of current through electrolytic conductors is accomplished by the movement of electric charges (positive and negative ions) when the liquid is under the influence of an electrical field. The conductance of a liquid can be defined by its electrical properties—the ratio of current to voltage between any two points within the liquid. As the two points move closer together or further apart, this value changes. To have useful meaning for analytical purposes, a dimension needs to be given to the measurement; i.e., the physical parameters of the measurement.

Weight of Water 100×Weight of Soil

-----------------------------------------------------------

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By defining the physical parameters of the measurement, a standard measure is created. This standard measure is referred to as specific conductance or electrical conductivity. It is defined as the reciprocal of the resistance in ohms, measured between the opposing faces of 1 cm cube of liquid at a specific temperature. The units used to define conductance are: 1/ohm = 1 mho = 1000 mS = 1,000,000 µS. S.I. units may be used in place of mhos; 1 mho = 1 Siemen (S).

Since K (cell constant) is a “factor” which reflects a particular cell’s physical configuration, it must be multiplied by the observed conductance to obtain the actual conductivity reading. For example, for an observed reading of 200 µS using a cell with K = 0.1, the conductivity value is 200 x 0.1 = 20 µS/cm. Solutions with low conductivity, up to 1-2 mS/cm, are best measured with cells having a cell constant of K = 0.1. Cells with K = 1.0 are best used for solutions with conductivity of >1 µS/cm to 200 mS/cm.

In theory, a conductivity measuring cell is formed by two 1-cm square surfaces spaced 1 cm apart. Cells of different physical configuration are characterized by their cell constant, K. The cell constant is a function of the electrode areas, the distance between the electrodes and the electrical field pattern between the electrodes. The theoretical cell just described has a cell constant of K = 1.0. Often, for considerations having to do with sample type, volume, or space, a cell’s physical configuration is designed differently.

In a simplified approach, the cell constant is defined as the ratio of the distance between the electrodes, d, to the electrode area, A. This however neglects the existence of a fringe-field effect, which affects the electrode area by the amount AR. Therefore K = d/(A + AR).

Because it is normally impossible to measure the fringe-field effect and the amount of AR to calculate the cell constant, K, the actual K of a specific cell is determined by a comparison measurement of a standard solution of known conductivity (e.g., 0.01 M KCl is a 1412 µS/cm standard at 25 °C).

40


Definition of Sodium Adsorption Ratio (SAR)SAR indicates the degree to which the negative charges of a soil's colloidal capacity have been neutralized by the sodium ion. Increasing SAR values indicate a build-up of exchangeable sodium in the soil which can result in decreased water infiltration and percolation, as well as pH values above 8.5. As a general rule, divalent cations tend to keep the soil permeable (flocculated) while monovalent cations, especially sodium, tend to deflocculate the soil through dispersion of the colloids. As soils become more sodic and alkaline, they begin to lose their natural structure and permeability due to both colloidal dispersion and the hydroxide induced dissolution of the soil humus.

SAR is a calculated value based on calcium, magnesium, and sodium values obtained from chemical analysis of the saturation extract. The formula for SAR is:

The units for Na+, Ca++, and Mg++ are meq/L

pH TheorypH is a measure of the hydrogen ion activity in a solution and is defined as: -log10 aH+ where aH+is the activity of the hydrogen ion. The 0-14 range of pH measurement is the measurement of a difference in hydrogen ion concentration of 100,000,000,000,000 (1 x 1014). This means that at pH 0 the hydrogen ion concentration is 1 x 1014 times greater than at pH 14.

This also means that the hydroxyl ion concentration at pH 14 is 1 x 1014 times greater than at pH 0.

When the hydrogen and hydroxyl ions are present in equal numbers (the neutral point), the pH is 7. pH values from 0 to 7 are

SAR Na

Ca + Mg2

----------------------⎝ ⎠⎛ ⎞

½---------------------------------=

Classification Criteria for Salt-Affected Soils

Soil Type ECse SAR pHsp

Saline >2.0 dS/m < 13 < 8.5

Sodic <2.0 dS/m > 13 > 8.5

Saline/Sodic >2.0 dS/m > 13 < 8.5

41


termed acidic and those from 7 to 14 are termed basic. It is important to note that a pH change of one unit (for instance from pH 6 to pH 7) is a factor-of-10 change in hydrogen ion concentration.

The glass membrane of a pH electrode responds to the hydrogen ion activity by developing an electrical potential at the glass/liquid interface. At a constant temperature, this potential varies linearly with the pH of the solution being measured. The change in potential per pH unit is termed the slope of the electrode. The slope of the electrode increases linearly with temperature.

The potential inside the pH glass bulb is fixed by the filling solution, and the reference electrode potential is constant. For these reasons, any change in the potential of the electrode system at a given temperature will be due to a change in the pH of the solution being measured.

Effects of temperature on pH measurements depend on the reference electrode used, pH of the solution within the pH electrode and pH of the test solution. At a certain pH, temperature will have no effect on the potential of the electrode system. This is known as the isopotential point. Also, at some pH level, the system will exhibit no potential. This is known as the zero potential point. Both the isopotential point and the zero potential point are features designed into electrodes. Hach electrodes are designed so the isopotential and zero potential points are at pH 7 to minimize temperature effects at this calibration point.

Platinum Series pH Electrode Operation PrincipalThe Hach Platinum Series pH Electrode is a combination pH electrode which employs a patented* free-flowing reference junction concept. Diluted electrolyte and contaminants are removed from the junction after each pump to ensure stable, reproducible reference potentials.

The reference electrolyte gel acts as a restriction device to control the release of potassium chloride (KCl) into the sample, in much the same way as a frit does in a conventional reference electrode.

* U.S. patent number 5397452

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The Hach electrode does not clog, become contaminated or carry over contaminants to the next sample because the restrictive device is renewed by pumping new gel.

A low-resistance glass measuring bulb provides quick, stable readings even in samples of low ionic strength. Although low-resistance glass requires less conditioning, it has less durability at high temperatures. In addition, a moderate sodium error occurs at pH levels greater than 12 when low-resistance glass is used.

Electrodes supplied with an internal temperature sensor accurately measure the pH of samples at temperatures different from calibration standard temperatures. This is accomplished using an automatic temperature compensation (ATC) program that is included in all Hach pH meters.

Sodium Electrode Description The Hach Sodium Electrode uses a sodium-selective glass membrane and contains an inner filling solution with a constant sodium ion concentration. Glycerol is utilized as an antifreeze agent. The glass used is LAS (lithium aluminosilicate) glass with special doping agents for improved selectivity for sodium ions.

The ideal sodium ion selective electrode responds (has a potential across the glass membrane) to sodium ions. However, sodium electrodes are not perfectly selective and respond to other ions such as potassium, lithium, hydrogen, silver and ammonium. The industry standard sodium glass electrode is made of NAS 11-18 glass that is 500-2000 times more sensitive to sodium than to potassium ions. The Hach glass has a selectivity coefficient of greater than 20,000 for sodium over potassium. Linearity, response speed, and conditioning time also are improved slightly.

The Sodium Combination Electrode incorporates a glass sodium half-cell and a reference half-cell. The reference half-cell uses a silver-silver chloride reference element in a specially designed free-diffusion junction. The reference element is encased in Teflon® tubing through which electrolyte gel is dispensed.

Electrolyte flows out through the open end of the tube and into the sample solution without restriction. Traditional porous

43


junctions often become clogged by precipitated silver chloride which can cause large and unknown junction potentials that result in measurement errors. The Hach Platinum Series free-flowing junction produces fast, stable potentials.

Sodium Electrode Theory The glass sensing membrane in the probe is in contact with an internal filling solution and the external sample solution. A constant potential is maintained inside the glass bulb due to the fixed ion concentrations of the internal filling. The outer hydrated surface of the glass bulb can exchange sodium ions with the sample solution, setting up a potential which is proportional to the concentration of sodium ions in solution.

A reference electrode is required to complete the electrical circuit through the pH/mV meter, and establish a stable, reproducible potential. In the complete electrochemical cell, consisting of the reference and indicator half cells, only the potential across the sensing membrane should vary.

The measured cell potential is related to the sodium ion concentration by the Nernst Equation:

E = E° - S log aNa

Where:

E = measured cell potential in millivolts E° = “standard” electrode potential S = 2.3RT/F, slope factor dependent on temperature aNa = activity of sodium ions

Response TimeThe response of the sodium electrode may take from 3-5 minutes to reach 95% of its total response for decade changes in sodium concentration. Generally, conditioning the electrode in sodium standards (containing Sodium and Potassium ISA) near the concentration to be measured provides fastest equilibrium. If the electrode response is slower than usual, try cleaning the glass membrane. Refer to Cleaning the Electrode in the Hach Platinum Series Sodium Electrode Manual, Cat. No. 48670-88.

44


InterferencesThe sodium glass membrane responds to a number of ions other than sodium, so interferences exist. Typically, electrode response to another ion increases the potential, causing a positive error. The response to other ions can be semi-quantitatively determined through the Nicholsky equation, an extended Nernst equation:

E = E° + (RT/zF) ln [aNa + KNaX • aX]

Where:

aX = the activity of the interfering ion KNaX = the selectivity coefficient for the interfering ion relative to sodium.

The value of the selectivity coefficient should be small to reduce the interference. A major advantage of the Hach Sodium electrode is the lower interferences from other ions compared to the standard sodium selective glass (NAS 11-18). If the electrode is exposed to high levels of interferences, soaking in Sodium Electrode Storage Solution or 1 M sodium chloride will help remove the adsorbed ions from the glass membrane.

The major interferences are silver ion and hydrogen ion. Hydrogen ion concentration is compensated for by measuring pH, then entering the required information into the SoilSYS™ Software. Calculations performed by the software accurately compensate for hydrogen activity using a modified Nicholsky equation.

Effect of Ionic StrengthThe probe actually senses sodium ion activity, not concentration. The activity (the thermodynamic “force” of the ions) is related to the concentration:

aNa = CNa x ƒ

Where:

aNa = activity of sodium ions cNa = concentration of sodium ions ƒ = activity coefficient

The activity coefficient varies with ionic strength (a measure of total number of ions in the solution). Because the sodium

45


concentration is usually what is measured, control of the ionic strength is a part of most procedures. The use of conductivity measurements and SoilSYS™ Software allows the calculation of activity versus mV.

Raising the ionic strength to a high value by ionic strength adjustors is the common method of ensuring all samples have the same ionic strength. In this sodicity method, temperature, pH and conductivity are used to calculate activity versus mV, eliminating the need to use an ionic strength adjustor. Concentration is then related to activity.

Effect of TemperatureThe formula for potential given above indicates that the slope of the response, and therefore the actual potential, depends on the temperature. Normally all standards and samples should be measured at the same temperature (within 1 °C).The Soil SYS software compensates for varying temperatures with a temperature term in the equations used to calculate activity.

46

APPENDIX B DATA ENTRY TABLES

Photocopy the tables that follow to record calibration data and data collected in the field. To facilitate entry of data, the order of the table is the same as the grid in the SoilSYS™ Software.

Conductivity Cup Calibration Information

Saturated Soil Paste Sample Data

Calibration Information

Calibration Point 1

Calibration Point 2

Calibration Point 3

Calibration Point 4

Calibration Point 5

Conductivity

Temperature

Cup Reading

Sample Number

Location Date SurveyorDepth

(inches)Sub-

samplesArea

(acres)Weight

(g)

Cup Reading

(mS)

Temp (°C)

pHpSodium

(mV)

47

APPENDIX B, continued

Sodium Calibration Information

Irrigation Water Sample Data

Calibration Information

Calibration Point 1

Calibration Point 2

Calibration Point 3

Calibration Point 4

Calibration Point 5

Concentration

mV Reading

Cup Reading

Standard pH

Standard Temperature

Sample Number

Location Date SurveyorCup

Reading (mS)

Temp (°C) pHSodium

(mV)

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GENERAL INFORMATION

49

At Hach Company, customer service is an important part of every product we make.

With that in mind, we have compiled the following information for your convenience.

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REPLACEMENT PARTS

REQUIRED REAGENTS AND APPARATUS FOR SALINITY TESTINGDescription Unit Cat. No.Balance, AccuLab, Pocket Pro.................................................................each .............25568-00Beaker, Snap-top, 120 mL........................................................................each .............25522-00Buffer Pillows, pH 7, ...........................................................................50/pkg .............22270-66Buffer Pillows, pH 10, .........................................................................50/pkg .............22271-66Brush, nylon, for cleaning conductivity cups...........................................each .................690-00Clippers, Large, for opening Powder Pillows ..........................................each .................968-00Conductivity Cup ..................................................................................2/pkg .............45720-00Conductivity Cup Base.............................................................................each .............45723-00sension™ 5 Portable Conductivity Meter................................................each .............51800-00Cups, 5 ounce, for mixing soil paste ..................................................... sleeve .............22631-74Electrode, pH, Platinum Series ................................................................each .............51910-00Lids, for Cat. No. 22631-74 cups .......................................................... sleeve .............22632-47Polishing Cloth.........................................................................................each .............44511-00Potassium chloride electrolyte cartridge (for pH electrode) ..................2/pkg .............25469-02sension™1 Portable pH/ISE Meter .........................................................each .............51700-00SoilSYS™ Software.................................................................................each .............49625-00Soil Sieve..................................................................................................each .............46159-00Sodium Standard, 4.35 mmol..............................................................500 mL.............23181-49Sodium Standard, 43.5 mmol..............................................................500 mL.............14749-49Sodium Standard, 175 mmol...............................................................500 mL.............23074-49Spatula, for mixing saturated soil paste ...................................................each .............56164-00Wash Bottle ..............................................................................................each .................620-14Water, Deionized .................................................................................500 mL.................272-49

REQUIRED REAGENTS AND APPARATUS FOR SODICITY TESTINGAmmonium chloride electrolyte cartridge (for sodium electrode).........2/pkg .............25958-02Electrode, Sodium, Platinum Series.........................................................each .............51925-00Sodium Standard, 4.35 mmol..............................................................500 mL.............23181-49Sodium Standard, 43.5 mmol..............................................................500 mL.............14749-49Sodium Standard, 175 mmol...............................................................500 mL.............23074-49

REPLACEMENT PARTSConductivity Cup ..................................................................................2/pkg .............45720-00Conductivity Cup Base.............................................................................each .............45723-00SIW Salinity Appraisal Lab and Sodicity Analysis Package Manual......each .............27162-88SoilSYS™ Software User’s Guide...........................................................each .............49625-88Soil and Irrigation Water Interpretation Manual ......................................each .............24959-89

OPTIONAL APPARATUSSoil Sampling Tube, Dry Soil, 30.5 cm ...................................................each .............20589-12Soil Sampling Tube, Dry Soil, 46.0 cm ...................................................each .............20589-18Thermometer, Pocket, -5 to 45 °C............................................................each .............26763-00

HOW TO ORDER

Information Required

Technical and Customer Service (U.S.A. only)Hach Technical and Customer Service Department personnel are eager to answer questions about our products and their use. Specialists in analytical methods, they are happy to put their talents to work for you. Call 1-800-227-4224 or E-mail [email protected].

International CustomersHach maintains a worldwide network of dealers and distributors. To locate the representative nearest you, send E-mail to intl@hach. com or contact:

In Canada, Latin America, Africa, Asia, Pacific Rim:Telephone: (970) 669-3050; FAX: (970) 669-2932

In Europe, the Middle East, or Mediterranean Africa: HACH Company, c/o Dr. Bruno Lange GmbH Willstätterstr. 11 D-40549 Düsseldorf Germany Telephone: +49/[0]211.52.88.0 Fax: +49/[0]211.52.88.231

By Telephone: By Mail:6:30 a.m. to 5:00 p.m. MST Monday through Friday (800) 227-HACH (800-227-4224) By FAX: (970) 669-2932

Hach Company P.O. Box 389 Loveland, CO 80539-0389 U.S.A.

Ordering information by E-mail: [email protected]

• Hach account number (if available) • Billing address

• Your name and phone number • Shipping address

• Purchase order number • Catalog number

• Brief description or model number • Quantity

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REPAIR SERVICE

Authorization must be obtained from Hach Company before sending any items for repair. Please contact the HACH Service Center serving your location.

In the United States: Hach Company 100 Dayton Avenue Ames, Iowa 50010 (800) 227-4224 (U.S.A. only) Telephone: (515) 232-2533 FAX: (515) 232-1276

In Canada: Hach Sales & Service Canada Ltd. 1313 Border Street, Unit 34 Winnipeg, Manitoba R3H 0X4 (800) 665-7635 (Canada only) Telephone: (204) 632-5598 FAX: (204) 694-5134 E-mail: [email protected]

In Latin America, the Caribbean, the Far East, the Indian Subcontinent, Africa, Europe, or the Middle East: Hach Company World Headquarters P.O. Box 389 Loveland, Colorado, 80539-0389 U.S.A. Telephone: (970) 669-3050 FAX: (970) 669-2932 E-mail: [email protected]

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WARRANTY

Hach warrants most products against defective materials or workmanship for at least one year from the date of shipment; longer warranties may apply to some items.

HACH WARRANTS TO THE ORIGINAL BUYER THAT HACH PRODUCTS WILL CONFORM TO ANY EXPRESS WRITTEN WARRANTY GIVEN BY HACH TO THE BUYER. EXCEPT AS EXPRESSLY SET FORTH IN THE PRECEDING SENTENCE, HACH MAKES NO WARRANTY OF ANY KIND WHATSOEVER WITH RESPECT TO ANY PRODUCTS. HACH EXPRESSLY DISCLAIMS ANY WARRANTIES IMPLIED BY LAW, INCLUDING BUT NOT BINDING TO ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

LIMITATION OF REMEDIES: Hach shall, at its option, replace or repair nonconforming products or refund all amounts paid by the buyer. THIS IS THE EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY.

LIMITATION OF DAMAGES: IN NO EVENT SHALL HACH BE LIABLE FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND FOR BREACH OF ANY WARRANTY, NEGLIGENCE, ON THE BASIS OF STRICT LIABILITY, OR OTHERWISE.

This warranty applies only to Hach products purchased and delivered in the United States.

Catalog descriptions, pictures and specification, although accurate to the best of our knowledge, are not a guarantee or warranty.

For a complete description of Hach Company’s warranty policy, request a copy of our Terms and Conditions of Sale for U.S. Sales from our Customer Service Department.

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®AccuGrow H O University™ Pond In Pillow™2® ®AccuVac H OU™ PourRite2

®AccuVer™ Hach Logo PrepTab™®AccuVial™ Hach One ProNetic™®Add-A-Test™ Hach Oval Pump Colorimeter™

®AgriTrak™ Hach.com™ QuanTab®AluVer HachLink™ Rapid Liquid™

AmVer™ Hawkeye The Hach Guy™ RapidSilver™®APA 6000™ HexaVer Ratio™

®AquaChek™ HgEx™ RoVer® ® sension™AquaTrend HydraVer

SM® Simply AccurateBariVer ICE-PIC™® SINGLET™BODTrak™ IncuTrol

SofChek™BoroTrace™ Just Add Water™® ® SoilSYS™BoroVer LeadTrak

® SP 510™C. Moore Green™ M-ColiBlue24® Spec√™CA 610™ ManVer

®® ® StablCalCalVer MolyVer®® ® StannaVerChromaVer Mug-O-Meter

® SteriChek™ColorQuik NetSketcher™®® ® StillVerCoolTrak NitraVer®® ® SulfaVerCuVer NitriVer

®® ® Surface ScatterCyaniVer NTrak®® TanniVerDigesdahl OASIS™®® TenSetteDithiVer On Site Analysis.

SMResults You Can Trust Test ‘N Tube™Dr. F. Fluent™OptiQuant™ SMTestYES!Dr. H. Tueau™OriFlow™ ®TitraStirDR/Check™OxyVer™ ®TitraVerEC 310™PathoScreen™® ToxTrak™FerroMo

®PbEx ®® UniVerFerroVer®PermaChem® VIScreen™FerroZine

®PhosVer ®VoluetteFilterTrak™ 660Pocket Colorimeter™ WasteAway™Formula 2533™Pocket Pal™ ®Formula 2589™ ZincoVerPocket Turbidimeter™®Gelex

HACH Company Trademarks HACH Technical Training Center

HACH analytical training programs

Workshops in analytical theory and procedure, and in the application of Hach products, are available in cities across the United States and at the HACH Technical Training Center in Loveland, Colorado. Find the latest schedule of

classes and locations by visiting our website (www.hach.com).

HACH Technical Training Center (HTTC)

HTTC offers technical training workshops for a wide variety of applications. Our purpose is to help analysts from all backgrounds understand analytical theory, gain practical, hands-on experience with instrumentation and chemistries, and return to their jobs with increased understanding and confidence.

To register for an HTTC workshop:

Review class descriptions to determine the workshop you wish to attend, then check the class schedule and class fees before registering. There are no prerequisites for any of the workshops.

You may use the online HTTC registration form, e-mail [email protected], call 800-227-4224, extension 2391, or fax 970-461-3915. From outside the United States, call 970-669-3050, extension 2391.

When you register for a workshop, please provide your HACH customer number (if you have one) and a purchase order number or credit card number to reserve your space in the class. After your registration has been processed, a confirmation packet will be sent to you. Please wait for registration confirmation before making travel arrangements. An invoice will be mailed under separate cover.

If you are outside the United States, training is frequently available directly from your local HACH Distributor. Please contact your distributor or the HACH International Department for more information.

SIW Salinity Appraisal LabandSodicity Analysis Package

27162-88ad/dk 10/04 2ed

HACH COMPANY World HeadquartersP.O. Box 389Loveland, Colorado 80539-0389Telephone: (970) 669-3050Fax: (970) 669-2932

For Technical Assistance, Price Information and Ordering:In the U.S.A. - Call toll-free 800-227-4224Outside the U.S.A. - Contact the HACH office or distributor serving you.On the Worldwide Web - www.hach.com; E-mail - [email protected]

SIW Salinity Appraisal Lab and Sodicity Analysis...

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