**First, Combined Fertilizer Testing Method**
**Compound Fertilizer Nitrogen Test:**
(a) Ask the user to prepare concentrated sulfuric acid (98% analytical grade).
(b) Determination Procedures:
1. Weigh and grind 1.000 g of compound fertilizer into a small 50 ml bottle. Add 20 ml of distilled water to dissolve the fertilizer, then add 3 ml of concentrated sulfuric acid. Heat the mixture over low heat while shaking until the solution is reduced to about half. Remove from heat, let it cool, and transfer the solution to a 100 ml volumetric flask. Dilute to volume with distilled water. Take 1 ml of this solution and place it in another 100 ml volumetric flask, diluting again with distilled water. This is the test solution.
2. Pipette 5 ml of distilled water into a clean beaker to make a blank solution.
3. Pipette 5 ml of the test solution into another clean beaker.
4. Pipette 5 ml of an 8 ppm ammonium nitrogen standard solution into another clean beaker.
5. Add 5 ml of phenol solution and 10 ml of sodium hypochlorite to each beaker, followed by 20 ml of distilled water. Shake well and let stand for 30 minutes.
6. Perform colorimetric measurement using the instrument. Refer to the instrument’s manual for detailed instructions.
(c) Calculation of Results:
Fertilizer nitrogen (%) = Instrument test value × 100/1 × 100/1 × 100/106
Where:
- The first two 100s represent the dilution factors during sample preparation.
- The first "1" refers to the mass of the sample taken.
- The second "1" refers to the volume of the sample taken.
- 100/106 is used to convert ppm to percentage content.
**Compound Fertilizer Phosphorus Test:**
(a) Preparation of reagents:
1. Prepare citric acid leaching agent by dissolving one bag of citric acid in 200 ml of distilled water.
2. Prepare molybdenum sulfate antideveloper by dissolving 1.5 g of ascorbic acid in 100 ml of molybdenum sulfate solution. (Note: This solution should be prepared on the day of use.)
(b) Test Steps:
1. Weigh and grind 0.200 g of compound fertilizer into a flask or plastic bottle. Add 30 ml of citric acid leaching agent. Stir for 30 minutes, filter through medium-speed non-phosphorus filter paper, and pipette 1 ml of filtrate into a 100 ml volumetric flask. Dilute to volume with distilled water. This is the test solution.
2. Pipette 5 ml of distilled water into a clean beaker as the blank.
3. Pipette 5 ml of the test solution into another clean beaker.
4. Pipette 5 ml of a 2 ppm effective phosphorus standard solution into another clean beaker.
5. Add 5 ml of molybdenum sulfate antideveloper to each beaker, remove any gas, add 40 ml of distilled water, and shake for 30 minutes.
6. Perform colorimetric measurement using the instrument. Refer to the manual for detailed instructions.
(c) Calculation of Results:
Fertilizer phosphorus content (P₂O₅%) = Measured solution content × 30/0.2 × 100/1 × 100/106 × 2.2913
Where:
- 30 and 100 are dilution factors during sample preparation.
- 0.2 is the mass of the sample taken.
- 1 is the volume of the sample taken.
- 100/106 converts ppm to percentage content.
- 2.2913 is the conversion factor from P to Pâ‚‚Oâ‚….
**Compound Fertilizer Potassium Test:**
(a) Determination Procedures:
1. Weigh and grind 0.500 g of compound fertilizer into a flask or plastic bottle. Add 30 ml of distilled water, stir for 30 minutes, and filter with medium-speed filter paper. Pipette 1 ml of filtrate into a 100 ml volumetric flask, dilute with distilled water to half volume, add 1–2 drops of 10% sodium hydroxide solution, boil for 5 minutes, cool, and dilute to volume. This is the test solution.
2. Pipette 10 ml of distilled water into a clean beaker for the blank solution.
3. Pipette 10 ml of the test solution into another clean beaker.
4. Pipette 10 ml of a 20 ppm available potassium standard solution into another clean beaker.
5. Add 10 drops of disodium EDTA solution and 2 ml of formaldehyde solution to each beaker. Then add 2 ml of sodium tetraphenylborate solution and 40 ml of distilled water. Shake and let stand for 5–10 minutes.
6. Perform colorimetric measurement using the instrument. Refer to the manual for detailed instructions.
(b) Calculation of Results:
Fertilizer potassium content (K₂O%) = Measured solution content × 30/0.5 × 100/1 × 100/106 × 1.2046
Where:
- 30 and 100 are dilution factors.
- 0.5 is the mass of the sample taken.
- 1 is the volume of the sample taken.
- 100/106 converts ppm to percentage content.
- 1.2046 is the conversion factor from K to Kâ‚‚O.
**Second, Simple Fertilizer Testing Method**
**Nitrogen Fertilizer Test:**
(a) Urea Test:
The procedure for testing urea is the same as that for compound fertilizer nitrogen, except that 1 g of sample is weighed instead of 0.2 g.
(b) Other Simple Nitrogen Fertilizers:
1. Prepare the test solution by weighing 1.000 g of the sample and dissolving it in 100 ml of distilled water. Dilute again by taking 1 ml of the solution and placing it in another 100 ml volumetric flask. This is the test solution.
2. Follow the same testing process and calculation method as for the compound fertilizer nitrogen test.
**Phosphate Test:**
The method and calculation for phosphate fertilizer are identical to those for compound fertilizer phosphorus.
**Potassium Test:**
1. Prepare the test solution by weighing 1.000 g of the sample, dissolving it in 50 ml of distilled water, and taking 1 ml of the solution to dilute to 100 ml. This is the test solution.
2. Follow the same testing process and calculation method as for compound fertilizer potassium.
**Hangzhou Top Instrument Co., Ltd.**
Room 806, Songdu Building, No. 69 Wangjiang Road, Hangzhou
Phone: 86062776
Fax: [Not provided]
Golf Mat,Portable Mini Practice Golf Mat,Indoor Golf Mat,Portable Practice Putting
Yantai UVT Sports Co.,Ltd. , https://www.uvtgolf.com