Data quality requirements, for the analysis of soil and land applied material for the Nutrient Management Act, are given in this section.

Laboratories may use the methods that are referenced under specific tests or other validated methods that meet data quality requirements as given under each test.

4.1 Guidance on Selecting Laboratories for Analysis

A listing of laboratories accredited under the OMAFRA Agronomic Test Accreditation Program is available from the Ontario Ministry of Agriculture, Food and Rural Affairs at any of its offices, in the crop production recommendation publications (e.g. OMAFRA publications 360, 363, 811), or from the OMAFRA website.

Laboratories may be accredited to ISO/IEC 17025 standards within Canada by either the Standards Council of Canada (SCC), or the Canadian Association for Laboratory Accreditation Inc. (CALA).

A directory of SCC accredited laboratories within Canada may be obtained from the Standards Council of Canada, 270 Albert Street, Suite 200, Ottawa ON, K1P 6N7. Telephone: (613) 238-3222 Fax: (613) 569-7808. This information may also be obtained from their website.

A listing of CALA accredited labs can be obtained by contacting:

Canadian Association for Laboratory Accreditation Inc.
310-1565 Carling Avenue
Ottawa, ON K1Z 8R1
Telephone: (613) 233-5300 
Fax: (613) 233-5501.

This information may also be obtained from their website.

4.2 Soil Analysis

4.2.1 Soil pH

Matrix: Soil

Analysis

This analysis is required at least once within the five years prior to nutrients being applied. Soil pH is measured in a saturated paste.

Method Principle

Soil pH is determined with a standard glass electrode pH meter in a saturated soil-water paste.

Sample Preparation

Samples must be air dried and crushed to pass a 2 mm sieve.

Add sufficient distilled water to air-dried, crushed soil to make a saturated paste. There should not be any free water on top of the soil sample. Hand mix the sample well using a glass rod, and allow to stand for 15-20 minutes.

Instrumentation

Standardize the pH meter with both pH 7.00 and pH 4.00 buffers. Insert the pH electrodes into the paste and determine the pH while slowly moving the electrodes within the paste.

Laboratory QC Samples per Run

Calibrate the pH meter, according to manufacturer’s directions, before each set of analysis.

Method Performance Criteria

Inter- and intra-lab precision must be within ± 0.3 pH units of the mean of samples from all accredited labs.

Reference Method

OMAFRA pH

4.2.2 Soil Buffer pH

Matrix: Soil

Analysis

This analysis is required to determine the lime requirement of soil samples with a soil pH below 6.0. Buffer pH is measured into a sample of previously dried, crushed soil mixed with a Shoemaker-McLean-Pratt (SMP) buffer solution.

Method Principle

The reduction in pH of a standard buffer solution is measured to determine the amount of lime required to bring the soil pH of an acid soil into an acceptable range for crop production.

Sample Preparation

Samples must be air dried and crushed to pass through a 2 mm sieve.

Combine one part air dried crushed soil with two parts SMP buffer in a disposable beaker. Shake for 10-15 minutes, let stand 15 minutes then determine pH.

Instrumentation

Read the pH on a standardized pH meter, calibrated to both pH 4.00 and 7.00 buffer solutions, while electrodes are slowly moved within the suspension.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Inter- and intra-lab precision must be within ± 0.3 pH units of the mean of samples from all accredited labs.

Reference Method

OMAFRA BpH

4.2.3 Available Nutrients - Phosphorus

Matrix: Soil

Analysis

This analysis is required at least once within the five years prior to nutrients application. Plant available phosphorus is measured using the 0.5 M sodium bicarbonate method.

Method Principle

A portion of previously dried, crushed and sieved (< 2 mm) sample is extracted with a dilute alkaline solution, and P concentration is determined in the extract.

Sample Preparation

Samples must be air dried and crushed to pass a 2 mm sieve.

Shake one part air-dried crushed soil for 30 minutes with 20 parts of 0.5 M sodium bicarbonate extracting solution, then let settle and filter. Determine P concentration in extract in auto-analyzer and calculate mg P/L of soil.

Instrumentation

Set up the Autoanalyzer to develop the colour reaction by the molybdate – ascorbic acid method. Read the sample absorbance at a wavelength of 820 nm.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Inter- and intra-lab precision must be within ±15% of the mean of samples from all accredited labs.

Reference Method

OMAFRA P

4.2.4 Available Nutrients - K, Mg and Ca

Matrix: Soil

Analysis

Analysis of available potassium is required at least once within the five years prior to nutrients application. Analysis of available magnesium is not required as part of a NMP, but is very useful in determining the requirement for magnesium fertilizers for crop production. Some labs may also determine the calcium content of the soil from the same extract. Plant available cations are measured using the 1 M ammonium acetate method.

Method Principle

A portion of previously dried, crushed and sieved (< 2 mm), sample is extracted with a dilute ammonium acetate solution, and analyzed using a spectrometric technique.

Sample Preparation

Samples must be air dried and crushed to pass a 2 mm sieve.

Shake one part of air dried crushed soil with 10 parts of neutral 1 M ammonium acetate solution for 15 minutes. Let settle and then filter. Determine concentrations in extract on atomic absorption spectrophotometer.

Instrumentation

Potassium (K) is determined by atomic absorption spectrometry (AAS) in the emission mode at a wavelength of 766 nm.

Magnesium (Mg) is determined on the same extract at a wavelength of 285.2 nm AAS. If the sample reads over 400 absorbance units, it is diluted 1:9 with ammonium acetate and the results multiplied by a factor of 10.

Calcium (Ca) is read on same extract as Mg and K, but all samples are initially diluted 1:9 with ammonium acetate. Ca concentration is determined by AAS at a wavelength of 422.7 nm.

ICP may also be used to measure the concentration of cations in the extract.

Laboratory QC samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Inter- and intra-lab precision of the K analysis must be within ± 15% of the mean (± 20% for Mg) of samples from all accredited labs.

Reference Method

OMAFRA Cations

4.2.5 Available Nutrients – Zn, Zn Index

Matrix: Soil

Analysis

This analysis is not required as part of a NMP, but can be useful in determining whether a zinc deficiency might occur in crops. Soil zinc content is measured using the DTPA method. Results from this analysis are combined with soil pH to produce an index of zinc availability in agricultural soil.

Method Principle

A portion of previously dried, crushed and sieved (< 2 mm), sample is extracted with a DTPA solution and the concentration of zinc is determined on an Atomic Absorption Spectrophotometer. Zinc content and soil pH are used in a formula to produce an index of Zn availability.

Sample Preparation

Samples must be air dried and crushed to pass a 2 mm sieve.

Shake one part air dried crushed soil with 2 parts of DTPA extracting solution for 1 hour. Samples are allowed to settle and then filtered.

Instrumentation

Zinc is read by AAS in the emission mode at 213.9 nm.

ICP may also be used to measure the concentration of ions in the extract.

Zinc is reported by index using formula:

203 + 4.5 DPTA ext in mg/L - 50.7 soil pH + 3.33 (soil pH)².

Note: A small error in pH will cause a major change in the zinc index. E.g. if you take values for soil A as 4.8 paste and 5.2 (25 mL water), the resulting values if the Zn reading is 2 mg/L, are 50.3 and 43.44 respectively – a rather large error.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Inter- and intra-lab precision of the calculated index must be within ±15% of the mean of samples from all accredited labs.

Reference Method

OMAFRA Zn

4.2.6 Available Nutrients – Mn, Mn Index

Matrix: Soil

Analysis

This analysis is not required as part of the NMP, but is useful in determining whether manganese deficiency may occur in crops. Soil manganese content is measured using the 0.5 M phosphoric acid method. Results from this test are combined with soil pH to produce an index of manganese availability.

Method Principle

A portion of previously dried, crushed and sieved (< 2 mm), sample is extracted with a dilute phosphoric acid solution, and analyzed using an atomic absorption spectrophotometer.

Sample Preparation

Samples must be air dried and crushed to pass a 2 mm sieve.

Shake one part air dried crushed soil with 8 parts 0.5 M phosphoric acid extracting solution for 10 minutes. Let settle, and then filter.

Instrumentation

The manganese is read on an atomic absorption spectrophotometer at 279.5 manometers in the A.A. mode. ICP may also be used to measure the concentration of ions in the extract.

Manganese index is reported using the formula:

498 - 137 soil pH + 0.248 extracted Mn + 9.64 (soil pH)².

A small change in pH affects the index greatly.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Inter- and intra-lab precision of the calculated index must be within ± 15% of the mean of samples from all accredited labs.

Reference Method

OMAFRA Mn

4.2.7 Available Nutrients – Nitrate N

Matrix: Soil

Analysis

This analysis is not required in a NMP, but can be used to refine the nitrogen fertilizer application rates on corn or barley. Nitrate nitrogen is measured using the 2 M potassium chloride extraction.

Method Principle

A portion of previously dried, crushed and sieved (< 2 mm), sample is extracted with a dilute potassium chloride solution, and the concentration of nitrate in the extract determined using a colourimetric technique.

Sample Preparation  

Take frozen or air dried soil (if frozen allow to thaw approximately 2 hours at room temperature), and sieve through 2 or 4 mesh screen. Take smaller particles for nitrate analyses. Clay samples or extremely wet samples will not sieve properly, you may have to cut sample into smaller pieces, using a knife or spatula.

Shake one part fresh or air dried soil with 5 parts of 2 N KCl extracting solution for 30 minutes. Let settle and then filter.

Take a sample of rest of soil (5-15 g) for moisture analyses. Dry at 105°C overnight and calculate soil moisture.

Instrumentation

Nitrate is determined on an auto-analyzer using the cadmium reduction technique to reduce the nitrate to nitrite, followed by reaction with a colour agent and measurement of the absorbance at 520 nm.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Inter- and intra-lab precision must be within ± 15% of the mean of samples from all accredited labs.

Reference Method

OMAFRA NO3

4.2.8 Total Metals – Cd, Cr, Co, Cu, Pb, Mo, Ni, and Zn

Matrix: Soil

Analysis

Soils in fields that will be receiving non-agricultural source material must be analyzed for each of the above metals. Sampling and analysis frequencies are given in Section 1.3.1. Non-agricultural source material may not be applied to soil where any of the metal concentrations in soil are equal to or greater than those given in Tables 1.1 and 1.2.

Method Principle

A portion of previously dried, ground and sieved (< 0.355mm), sample is extracted with a heated, strong mixed acid solution, brought to volume with pure de-ionized water and analyzed using a spectrometric technique.

Sample Preparation

Instrumentation

ICP/OES

DCP, ICP/MS, flame AAS and graphite furnace AAS with suitable matrix modifiers may be used.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Analyte	RDL (μg/g)	Acceptable Bias (%)	Precision (Reproducibility) (% RDS)
Cadmium	1	± 20	± 20
Chromium	12	± 20	± 20
Cobalt	2.5	± 20	± 20
Copper	10	± 20	± 20
Lead	10	± 20	± 20
Molybdenum	2.5	N/A	N/A
Nickel	3.2	± 20	± 20
Zinc	25	± 20	± 20

* Bias is based upon the certified reference material, such as, NIST 2709, 2710, and 2711.

Reference Method

MOE/LaSB - E3073/E3470

4.2.9 Mercury

Matrix: Soil

Analysis

Soils in fields that will be receiving non-agricultural source material must be analyzed for mercury. Sampling and analysis frequencies are given in Section 1.3.1. Non-agricultural source material may not be applied to soil where mercury concentration in soil is equal to or greater than that given in Tables 1.1 and 1.2.

Method Principle

Mercury in the sample is converted to the inorganic form by the acid digestion process. The inorganic mercury in aqueous solution is then reduced with stannous chloride, and analyzed by Cold Vapour Flameless Atomic Absorption (CV AAS.)

Sample Preparation

Instrumentation

CV-AAS

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Analyte	RDL (μg/g)	Acceptable Bias (%)	Precision (Reproducibility) (% RDS)
Mercury	0.05	± 20	± 20

* Bias is based upon the certified reference material, such as, National Research Council Sediment - PACS-1 or NIST 1646 sediment.

Reference Method

MOE/LaSB - E3059

4.2.10 Arsenic and Selenium

Matrix: Soil

Analysis

Soils in fields that will be receiving non-agricultural source material must be analyzed for arsenic and selenium. The sampling and analysis frequencies are given in Section 1.3.1. Non-agricultural source material may not be applied to soil where concentrations of arsenic and selenium in soil are equal to or greater than those given in Tables 1.1 and 1.2.

Method Principle

A portion of sample is digested in an oxidizing acid mixture to convert all forms of arsenic and selenium to arsenate (AsO₄)^3- and selenate (SeO₄)^2- respectively. The arsenate and selenate are then reduced with sodium borohydride to arsine and hydrogen selenide which are then analyzed by flameless AAS.

Sample Preparation

Instrumentation

Hydride - Flameless Atomic Absorption Spectrophotometry (HYD-FAAS).

ICP/MS and graphite furnace AAS with suitable matrix modifiers may be used.

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control or CRM, Calibration Check and Sample Replicate.

Method Performance Criteria

Analyte	RDL(μg/g)	Acceptable Bias(%)	Precision (Reproducibility)(% RDS)
Arsenic	1.4	± 20	± 20
Selenium	1	± 20	± 20

* Bias is based upon the certified reference material, such as, NIST 2709 San Joaquin soil.

Reference Method 

MOE/LaSB - E3245

4.2.11 Boron - Hot Water Extraction

Matrix: Soil

Analysis

The regulation may require analysis of soils where application of materials high in boron is planned, on a case-by-case basis.

Method Principle

A 25 g portion of previously dried, ground (< 2 mm) sample is extracted with a weak calcium chloride solution and analyzed using a spectrometric technique.

Sample Preparation

Instrumentation

ICP (AAS or DCP may be used)

Laboratory QC Samples per Run

Method Blank, Matrix Matched In-House Control, Calibration Check and Sample Replicate.

Method Performance Criteria

Bias and precision data are under review.

Reference Method

MOE/LaSB - E3073

Note: This method can identify contaminated sites, but is not sensitive enough to identify potentially deficient sites for crop production.

 

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| Introduction | Sampling Methods | Laboratory Analysis |
| Data Quality Requirements - Part One | Data Quality Requirements - Part Two |
| Acronyms | Glossary |

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