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NY/T 525-2021 English PDF

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NY/T 525-2021: (organic fertilizer)
Status: Valid

NY/T 525: Evolution and historical versions

Standard ID	Contents [version]	USD	STEP2	[PDF] delivered in	Standard Title (Description)	Status	PDF
NY/T 525-2021	English	369	Add to Cart	4 days [Need to translate]	(organic fertilizer)	Valid	NY/T 525-2021
NY 525-2012	English	115	Add to Cart	0--9 seconds. Auto-delivery	Organic fertilizer	Obsolete	NY 525-2012
NY 525-2011	English	559	Add to Cart	4 days [Need to translate]	Organic fertilizer	Obsolete	NY 525-2011
NY 525-2002	English	479	Add to Cart	4 days [Need to translate]	Organic fertilizer	Obsolete	NY 525-2002

PDF similar to NY/T 525-2021

Standard similar to NY/T 525-2021

JISH1306 LY/T 1231 NY/T 394 NY/T 798 NY 884

Basic data

Standard ID	NY/T 525-2021 (NY/T525-2021)
Description (Translated English)	(organic fertilizer)
Sector / Industry	Agriculture Industry Standard (Recommended)
Classification of Chinese Standard	B10
Word Count Estimation	16,193
Issuing agency(ies)	Ministry of Agriculture and Rural Affairs

NY 525-2012: Organic fertilizer

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Organic fertilizer People's Republic of China agricultural industry standards Replacing NY 525-2002 organic fertilizer Posted2011-09-01 2011-12-01 implementation People's Republic of China Ministry of Agriculture released

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009. 4.2, 4.3 and 4.4 in Chapter 4 of this standard, Chapter 6, 7.1 and 7.2 in Chapter 7 are mandatory and the rest are recommended terms. This standard is NY 525-2002 "organic fertilizer" amendment. This standard replaces NY 525-2002 "organic fertilizer", compared with NY 525-2002 main changes. - Amended total As, Hg, Pb, Cd, total chromium; - Revision of mass fraction of organic matter, mass fraction of total nutrients (potassium phosphorus oxalate), moisture (fresh sample) Mass fraction, pH (pH); - Escherichia coli index revised as fecal coliform number of indicators; - Modify the method for determination of organic matter content by adding a correction factor of 1.5. This standard by the People's Republic of China Ministry of Agriculture Planting Management Division and centralized. This standard was drafted. National Agricultural Technology Extension Service Center, Nanjing Agricultural University, Soil and Fertilizer Station in Anhui Province, Jilin Province soil Soil fertilizer terminal. Cui Yong, Yang Fan, Li Rong, Shen Rong, Chu Jingdong, Li Xuan, Huang Lan, Sun Zhao, Dong Yan, paragraph IAC. This standard superseded standard previous versions released as follows. - NY 525-2002. organic fertilizer

1 Scope

This document specifies the technical requirements for organic fertilizers, test methods, inspection rules, labeling, packaging, transportation and storage. This document applies to livestock and poultry, animal and plant residues and animal and plant products as raw materials processed as raw materials, and fermented Cooked organic fertilizer made. This document does not apply to organic manure produced by green manure, peasant and other farmers.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version applies to this article Pieces. For undated references, the latest edition (including all amendments) applies to this document. GB/T 601 chemical reagent titration analysis (capacity analysis) prepared with standard solution GB/T 6679 General rules for sampling solid chemical products GB/T 6682 analytical laboratory water specifications and test methods GB/T 8170 rounded repair rules and limit values of the representation and judgment GB/T 8576 compound fertilizer free water content determination Vacuum oven method GB 18382 fertilizer labeling content and requirements GB 18877 organic - inorganic compound fertilizer GB/T 19524.1 Determination of fecal coliform bacteria in fertilizers GB/T 19524.2 Determination of Ascaris egg death rate in fertilizers HG/T 2843 chemical analysis of fertilizer products commonly used standard titration solution, standard solution, reagent solution and indicator solution NY 884 bio-organic fertilizer "Product Quality Arbitration Inspection and Product Quality Supervision and Management Measures" State Bureau of Quality and Technical Supervision Order No. 4 of.1999

3 Terms and definitions

The following terms and definitions apply to this document. Mainly from plants and (or) animals, after fermentation of carbonated organic materials maturity, its function is to improve soil fertility ,, provide Nutrition, improve crop quality. 3.2 Fresh Sample Fresh Sample Site collection of organic fertilizer samples.

4 requirements

4.1 Appearance Color is brown or beige, granular or powder, uniform, no foul, no mechanical impurities. 4.2 Organic fertilizer technical indicators should meet the requirements of Table 1. Table 1 Project Indicators Organic matter mass fraction (on a dry basis), (%) ≥45 The total nutrient (phosphorus pentoxide Phosphorus oxide) mass fraction (on a dry basis), (%) ≥ 5.0 Water (fresh) mass fraction, (%) ≤ 30 PH, (pH) 5.5-8.5 4.3 The limit indicator of heavy metals in organic fertilizers should meet the requirements in Table 2. Table 2 is in milligrams per kilogram Project limited indicators Total arsenic (As) (dry basis) ≤15 Total mercury (Hg) (on a dry basis) ≤2 Total lead (Pb) (on a dry basis) ≤50 Total cadmium (dry basis) ≤ 3 Total chromium (on a dry basis) ≤150 4.4 Roundworm egg mortality and fecal colony number of indicators should be consistent with the requirements of NY 884.

5 test methods

The water used in this document should be in accordance with the provisions of three water GB/T 6682. Reagents listed, except as indicated, refer to analytical reagents. Test The required standard solution in the test, prepared according to HG/T 2843 regulations. 5.1 appearance Visual, nasal olfactory determination. 5.2 Determination of organic matter content (potassium dichromate capacity method) 5.2.1 method principle With a quantitative potassium dichromate - sulfuric acid solution, the heating conditions, the organic fertilizer organic carbon oxidation, the excess potassium dichromate with Ferrous sulfate standard solution titration, while adding silica as a blank for testing. According to the consumption of oxidants before and after oxidation, there are calculations Machine carbon content, multiplied by a factor of 1.724, for the organic content. 5.2.2 instruments, equipment Laboratory equipment commonly used. 5.2.3 Reagents and preparation 5.2.3.1 Silica. Powdered. 5.2.3.2 Sulfuric acid (ρ 1.84). 5.2.3.3 potassium dichromate (K2Cr2O7) standard solution. C (1/6 K2Cr2O7) = 0.1 mol/L. Weigh after baking at 130 ° C for 3h ~ 4h potassium dichromate (reference reagent) 4.9031g, first dissolved in a small amount of water, and then transferred into 1L volume Volume bottle, diluted with water to the mark, shake spare. 5.2.3.4 potassium dichromate solution. C (1/6 K2Cr2O7) = 0.8 mol/L. Weigh potassium dichromate (analytical grade) 80.0g, first with a small amount of water dissolved, and then transferred into a 1 L volumetric flask, diluted to the mark, shake spare. 5.2.3.5 ferrous sulfate (FeSO4) standard solution. C (FeSO4) = 0.2 mol/L. Weigh (FeSO4 · 7H2O) (analytical grade) 55.6g, dissolved in 900m L water, add sulfuric acid (5.2.3.2) 20m L dissolved, diluted The exact concentration of this solution to 0.1 mol/L potassium dichromate standard solution (5.2.3.3) calibration, Now use the current calibration. C (FeSO4) = 0.2mol/L standard solution calibration. Pipette potassium dichromate standard solution (5.2.3.3) 20.00mL Add 150mL triangle Bottle, add sulfuric acid (5.2.3.2) 3mL ~ 5mL and 2 drops ~ 3 drops of o-morpholine indicator (5.2.3.6), with ferrous sulfate standard solution (5.2.3.5) titration. According to the standard titration of ferrous sulfate titration consumption according to equation (1) calculate the exact concentration of c. Where c1 - potassium dichromate standard solution concentration in units of moles per liter (mol/L); V1 - absorbed potassium dichromate standard solution volume, in milliliters (mL); V2 - titration volume consumed ferrous sulfate standard solution, in milliliters (mL). 5.2.3.6 o-morpholine indicator Weigh 0.695g of ferrous sulfate (analytical grade) and 1.485g of o-phenanthroline (analytical grade) in 100mL of water and shake well for later use. This instruction The agents are easily degenerated and should be kept in airtight brown bottles. 5.2.4 Determination steps Weigh dried sample Φ1mm sieve 0.2g ~ 0.5g (accurate to 0.0001g), placed in 500mL flask, accurately added 0.8 mol/L potassium dichromate solution (5.2.3.4) 50.0 mL, then add 50.0 mL of concentrated sulfuric acid (5.2.3.2), plus a bent neck funnel, Placed in boiling water until the water boiled for 30min. Remove to cool to room temperature, rinse the small funnel, wash solution taken in a triangular flask. Remove Erlenmeyer flask, the reaction was nondestructive into 250 mL volumetric flask, cooled to room temperature, constant volume, draw 50.0 mL solution in 250 mL flask , Add water about 100mL or so, add 2 drops to 3 drops of o-morpholine indicator (5.2.3.6) with 0.2mol/L ferrous sulfate standard solution (5.2.3.5) titration near the end point, the solution from green to dark green, and then drop by adding ferrous sulfate standard until the brick is red only. At the same time 0.2g (accurate to 0.001g) of silica (5.2.3.1) was weighed in place of the sample, following the same analytical procedure using the same test Agent, a blank test. If the amount of standard solution of ferrous sulfate used in titration of the sample is less than 1/3 of the amount of the standard solution of ferrous sulfate used in the blank test, You should reduce the sample size, re-measured. 5.2.5 Analysis of the results of the statement Organic matter content is expressed as the mass fraction of fertilizer, according to equation (2) Calculated. Where. c-- molar concentration of ferrous sulfate standard solution, expressed in moles per liter (mol/L); V0 - blank test, the volume of calibration standard solution consumption, in milliliters (mL); V - The volume of the calibration standard solution, in milliliters (mL) ,rized during the determination of the sample; 0.003 - the molar mass of one-fourth of a carbon atom in grams per mole (g/mol); 1.724 - coefficient of conversion from organic carbon to organic matter; 1.5 - Oxidation correction factor; m - dry-like quality, in grams (g); X0 - dry-like water content; D - points to take multiple, fixed volume/min volume, 250/50. 5.2.6 allowable difference 5.2.6.1 Take the arithmetic mean of the parallel analysis results as the measurement results. 5.2.6.2 The absolute difference between parallel determination results shall comply with the requirements of Table 3. table 3 Organic matter/(%) Absolute difference/(%) ω ≦ 40 0.6 40 < ω < 55 0.8 ω ≧ 55 1.0 The absolute difference between the results of different laboratories should meet the requirements of Table 4. Table 4 Organic matter (ω)/(%) Absolute difference/(%) ω ≦ 40 1.0 40 < ω < 55 1.5 ω ≧ 55 2.0 5.3 Determination of total nitrogen content 5.3.1 Methodology Organic nitrogen in organic fertilizer by sulfuric acid - hydrogen peroxide digestion, into ammonium nitrogen. Alkalized ammonia distilled off with boric acid solution Collect, titrate with standard acid solution, calculate the total nitrogen content in the sample. 5.3.2 Reagents 5.3.2.1 Sulfuric acid (ρ1.84). 5.3.2.2 30% hydrogen peroxide. 5.3.2.3 sodium hydroxide solution. Mass concentration of 40% solution. Weigh 40g of sodium hydroxide (chemically pure) was dissolved in 100mL of water. 5.3.2.4 2% (m/V) boric acid solution. Weigh 20g boric acid dissolved in water, diluted to 1L. 5.3.2.5 Nitrogen mixed indicator. Weigh 0.5g bromocresol green and 0.1g methyl red dissolved in 100mL 95% ethanol. 5.3.2.6 boric acid - indicator mixture. Per liter of 2% boric acid (5.3.2.4) solution was added 20 mL of fixed nitrogen mixed indicator (5.3.2.5,) And dilute with dilute alkali or dilute acid purple (pH about 4.5). This solution should not be placed too long time, such as the use of pH changes, Need to be adjusted at any time with dilute alkali or dilute acid. 5.3.2.7 sulfuric acid [c (1/2H2SO4) = 0.05 mol/L] or hydrochloric acid [c (HCl) = 0.05 mol/L] standard solution. Preparation and calibration, in accordance with GB/T 601. 5.3.3 equipment, equipment Laboratory equipment and nitrogen constant distillation unit or Kjeldahl apparatus. 5.3.4 Analysis steps 5.3.4.1 Preparation of sample solution Weigh dried samples of Φ1mm sieve 0.5g ~ 1.0g (accurate to 0.0001g), placed in the bottom of the Kaiser flask, rinsed with a small amount of water Stained in the bottle wall sample, add 5mL sulfuric acid (5.3.2.1) and 1.5mL hydrogen peroxide (5.3.2.2), carefully shaken bottle neck put a bend Adjustable electric furnace slowly warmed to sulfuric acid smoke, remove, add a little cold and 15 drops of hydrogen peroxide, gently shaking open The flask was heated 10min, removed, slightly cold and then add 5 drops to 10 drops of hydrogen peroxide and digestion and decoction, until the solution was colorless or yellow After the color clear liquid, continue to heat 10min, except for the remaining hydrogen peroxide. Remove the cold, carefully add water to 20mL ~ 30mL, heated to boiling. Remove the cooling, with a small amount of water to wash the neck bend small funnel, lotion revenue Caesar original flask. Dispense liquid into 100 mL volumetric flask, add water Ding Rong, static clarification or filter with non-phosphorus filter plugged triangular flask, spare. 5.3.4.2 Blank test In addition to not adding the sample, the amount and operation of the same reagent 5.3.4.1. 5.3.4.3 Determination 5.3.4.3.1 Before distillation check whether the distillation unit leaks, and empty distillation to clean the pipe. 5.3.4.3.2 Pipette 50.0 mL digestion and decanting liquid in a distillation flask, add..200 mL water. In a 250 mL Erlenmeyer flask add 10 mL boric acid - indicator Agent mixture (5.3.2.6) to take the lower end of the condenser, the nozzle into the boric acid level. Slowly add 15 mL to the decanter from the funnel Sodium hydroxide solution (5.3.2.3), shut off the piston. Heating distillation, to be distilled liquid volume of about 100 mL, to stop distillation. 5.3.4.3.3 With sulfuric acid standard solution or hydrochloric acid standard solution (5.3.2.7) titration distillate, from blue to purple as the end point. Remember Record the volume of acid standard solution (mL). Blank determination of acid standard solution consumed volume of not more than 0.1mL, or should be re-measured set. 5.3.5 Analysis of the results of the statement The total nitrogen content of fertilizer to fertilizer mass fraction, according to equation (3) Calculated. c (V - V) 0.014 D 100 (%) m (1-X) N 3   (3) Where - C-- calibration standard solution molar concentration in units of moles per liter (mol/L); V0 - blank test, the consumption of calibration standard solution volume, in milliliters (mL); V-- sample determination, the consumption of calibration standard solution volume, in milliliters (mL); 0.014 - the molar mass of nitrogen in grams per mole (g/mol); m - air-like quality, in grams (g); X0 - dry-like water content; D - points to take multiple, set the volume/volume, 100/50. The result should be expressed in two decimal places. 5.3.6 allowable difference 5.3.6.1 Take the arithmetic mean of two parallel determination results as the determination result. 5.3.6.2 Two parallel determination results to allow the absolute difference should meet the requirements of Table 5. table 5 Nitrogen (N)/(%) Permissible difference · (%) N ≤ 0.50 < 0.02 0.50 \u003cN \u003c1.00 \u003c0.04 N ≥ 1.00 < 0.06 5.4 Determination of phosphorus content 5.4.1 Methodology Organic fertilizer samples with sulfuric acid and hydrogen peroxide digestion and digestion, at a certain acidity, the test solution of phosphate ions and metavanadic acid and molybdic acid reaction of the formation of yellow In a certain concentration range [1 mg/L ~ 20 mg/L], the yellow solution absorbance and phosphorus content was proportional to the relationship between spectrophotometry Quantitative phosphorus. 5.4.2 Reagents 5.4.2.1 Sulfuric acid (ρ 1.84). 5.4.2.2 Nitric acid. 5.4.2.3 30% hydrogen peroxide. 5.4.2.4 ammonium vanadate reagent. Solution A. Weigh 25.0 g of ammonium molybdate in 400 mL of water. Solution B. Weigh 1.25 g ammonium metavanadate dissolved in 300 mL boiling water, cool and add 250 mL nitric acid (5.4.2.2) and cool. The solution A was slowly injected into solution B while stirring, diluted to 1 L with water, mixed and stored in a brown bottle. 5.4.2.5 sodium hydroxide solution. Mass concentration of 10% solution. 5.4.2.6 Sulfuric acid (5.4.2.1). 5% by volume solution. 5.4.2.7 phosphorus standard solution. 50μg/mL. Weigh 0.2195g dried at 105 ° C for 2h potassium dihydrogen phosphate (reference reagent), dissolved in water, transferred to 1L volumetric flask, add Into 5 mL sulfuric acid (5.4.2.1), after cooling to volume with water to volume. 1 mL of this solution contained 50 μg of phosphorus (P). 5.4.2.8 2,4- (or 2,6-) dinitrophenol indicator. 0.2% by mass solution. 5.4.2.9 Non-phosphorus filter paper. 5.4.3 apparatus, equipment Laboratory equipment and spectrophotometer commonly used. 5.4.4 Analysis steps 5.4.4.1 Preparation of sample solution Prepare according to 5.3.4.1. 5.4.4.2 blank solution preparation In addition to not adding the sample, the application of reagents and operations with 5.4.4.1. 5.4.4.3 Determination Pipette 5.00 mL ~ 10.00 mL sample solution (5.4.4.1) (phosphorus 0.05 mg ~ 1.0 mg) in a 50 mL volumetric flask, add water To about 30 mL, and the same conditions with the standard solution color, colorimetric, read absorbance. 5.4.4.4 Calibration curve drawing Draw phosphorus standard solution (5.4.2.7) 0 mL, 1.0 mL, 2.5 mL, 5.0 mL, 7.5 mL, 10.0 mL, 15.0 mL were placed in seven 50 mL volumetric flask, and the sample solution was added and the same volume of a blank solution, add water to about 30 mL, add 2 drops of 2,4- (or 2,6-) The dinitrophenol indicator solution (5.4.2.8) is adjusted with sodium hydroxide solution (5.4.2.5) and sulfuric acid solution (5.4.2.6) Was slightly yellow, add 10.0 mL ammonium vanadate reagent (5.4.2.4), shake, water volume. This solution is 1 mL phosphorus (P) 0 μg, 1.0 μg, 2.5 μg, 5.0 μg, 7.5 μg, 10.0 μg, 15.0 μg of standard solution series. After 20 minutes at room temperature, at Spectrophotometer wavelength 440 nm 1) with 1 cm optical path cuvette, a blank solution to adjust the instrument zero, colorimetric, read the absorbance. Draw a standard curve or determine a linear regression equation based on phosphorus concentration and absorbance. * The wavelength of the choice of phosphorus concentration. Phosphorus concentration (mg/L) 0.75 ~ 5.5 2 ~ 15 4 ~ 17 7 ~ 20 Wavelength (nm) 400 440 470 490 5.4.5 Analysis of the results of the statement Fertilizer phosphorus content of the mass fraction of fertilizers, according to equation (4) Calculated. Where. c - obtained from the calibration curve or regression equation obtained phosphoric acid concentration of the color, in micrograms per milliliter (μg/mL); V - color development volume, 50mL; D - points to take multiple, constant volume/volume, 100/5 or 100/10; m - air-like quality, in grams (g); X0 - dry-like water content; 2.29 - Factor for conversion of phosphorus (P) to phosphorus pentoxide (P2O5) 0.0001 - Factor that converts μg/g to mass fraction. The result should be expressed in two decimal places. 5.4.6 allowable difference 5.4.6.1 take the arithmetic mean of two parallel determination results as the determination result. 5.4.6.2 The two parallel determination results to allow the absolute difference should meet the requirements of Table 6. Table 6 Phosphorus (P2O5), (%) Tolerance, (%) P2O5 < 0.50 < 0.02 0.50 \u003cP2O5 \u003c1.00 \u003c0.03 P2O5 ≥ 1.00 < 0.04 5.5 Determination of potassium content 5.5.1 Methodology Organic fertilizer samples were digested by sulfuric acid and hydrogen peroxide, diluted with flame spectrophotometry. In a certain concentration range, the solution of potassium Concentration and emission intensity was directly proportional relationship. 5.5.2 Reagents 5.5.2.1 Sulfuric acid (p 1.84). 5.5.2.2 30% hydrogen peroxide. 5.5.2.3 potassium standard stock solution. 1 mg/mL. Weigh 1.9067g 100 ° C baking 2h potassium chloride (reference reagent), dissolved in water after volume to 1L. The solution 1mL potassium (K) 1mg, stored in plastic bottles 5.5.2.4 potassium standard solution. 100 μg/mL. Draw 10.00 mL potassium (K) standard stock solution (5.4.2.3) in 100 mL volumetric flask, the volume of water, the solution 1 mL containing Potassium (K) 100 μg. 5.5.3 instruments, equipment Common laboratory equipment and flame photometer. 5.5.4 Analysis steps 5.5.4.1 Preparation of sample solution Prepared according to 5.3.4.1. 5.5.4.2 blank solution preparation In addition to not adding the sample, the reagents and procedures used are the same as those in 5.5.4.1. 5.5.4.3 Calibration curve drawing Draw potassium standard solution (5.5.2.4) 0 mL, 1.00 mL, 2.50 mL, 5.00 mL, 7.50 mL, 10.00 mL were placed in 5 50 mL Volumetric flask, add and draw the same volume of sample solution blank solution, water volume, the solution was 1 mL potassium (K) 0 μg, 2.00 μg, 5.00 μg, 10.00 μg, 15.00 μg, 20.00 μg of standard solution series. On a flame photometer, adjust with a blank solution Instrument zero, with the standard solution of the highest concentration of standard solution to adjust the full scale to 80 degrees. Then turn from low concentration to high concentration Measurement of other standard solution, record instrument value. Draw a calibration curve based on potassium concentration and instrument indication or find a linear regression equation. 5.5.4.4 Determination Pipette 5.00 mL sample solution (5.5.4.1) in 50 mL volumetric flask, water volume. The same conditions with the standard solution in the flame Measured on the photometer, record the value of the instrument. After each determination of 5 samples to be calibrated with potassium standard solution instrument. 5.5.5 Analysis of the results of the statement Fertilizer potassium content of the mass fraction of fertilizers, according to equation (5) Calculated. Where. c - obtained from the calibration curve or determined by the regression equation determination of potassium concentration in micrograms per milliliter (μg/mL); V - determination of the volume, the operation is 50mL; D - points to multiple, constant volume/volume, 100/5; m - air-like quality, in grams (g); X0 - dry-like water content; 1.20 - factor that converts potassium (K) to potassium oxide (K2O) 0.0001 - Factor that converts μg/g to mass fraction. The result should be expressed in two decimal places. 5.5.6 allowable difference 5.5.6.1 Take the arithmetic mean of two parallel determination results as the determination result. 5.5.6.2 two parallel determination of the absolute difference allowed to meet the requirements of Table 7. Table 7 Potassium (K2O), (%) Tolerance, (%) K2O ≤ 0.60 < 0.05 0.60 \u003cK2O \u003c1.20 \u003c0.07 1.2 \u003cK2O \u003c1.80 \u003c0.09 K2O ≥ 1.80 < 0.12 5.6 Determination of moisture content (vacuum oven method) According to GB/T 8576, were measured fresh water content, air-dried water content (X0). 5.7 Determination of pH (pH meter method) 5.7.1 method principle The sample is soaked in water for equilibrium and directly measured with a pH meter. 5.7.2 Instruments Laboratory equipment and pH pH meter. 5.7.3 Reagents and solutions 5.7.3.1 pH 4.01 standard buffer. Weigh 10.21g potassium hydrogen phthalate (KHC8H4O4) baked at 110 ℃ for 1h, dissolved in water, Dilute to volume 1L. 5.7.3.2 pH 6.87 standard buffer. Weigh 3.398g of potassium dihydrogen phosphate (KH2PO4) bake at 120 ° C for 2h and cool to 120 ° C ~ 130 ° C Bake 2h 3.55g anhydrous sodium phosphate dibasic (Na2HPO4), dissolved in water, dilute volume to 1L. 5.7.3.3 pH 9.18 standard buffer. Weigh borax (Na2B4O7 • 10H2O) (in a saturated solution of sucrose and salt desiccator Zhongping Balance week) 3.8g, dissolved in water, dilute volume to 1L. 5.7.4 Procedure Weighed Φ1mm sieve air-dried sample 5.0g in 100mL beaker, add 50mL of water (boil away carbon dioxide), stir 15min, Stand for 30min, measured with pH acid meter. 5.7.5 allowable difference Take the arithmetic mean of the parallel determination results as the final analysis result, leaving one decimal place. The absolute difference between parallel analysis results is not large At 0.2 pH units. 5.8 Determination of heavy metals 5.8.1 according to GB 18877. 5.8.2 Analysis of the results of the statement Heavy metal content of fertilizer to fertilizer mass fraction  (mg/kg), according to equation (6) Calculated. Where. ρ - measured by the calibration curve or determined by the regression equation Determination of heavy metal concentrations in solution, in micrograms per milliliter (μ g/mL); ρ0 - obtained by the calibration curve or regression equation obtained blank solution of heavy metal concentrations in micrograms per milliliter (μg/mL); V5 - Determination of volume; D - points to take multiple, set the volume/take volume; m - air-like quality, in grams (g); X0 - dry-like water content; The result retains a decimal. 5.9 Ascaris egg death rate determination According to GB/T 19524.2. 5.10 fecal coliform number determination According to GB/T...

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