Soil nutrient nitrogen, phosphorus and potassium tester;
The soil nutrient analyzer can detect the contents of available nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus, total potassium, organic matter, soil pH, salt content (swelling) and six kinds of trace elements such as calcium, magnesium, sulfur, boron, chlorine and silicon in soil and plants.
Rapid determination method of nutrients nitrogen, phosphorus and potassium in soil;
1, preparation of chemicals
1) preparation of soil extractant: take a bag of soil-bound extractant powder, put it in a 500mL volumetric flask, and add distilled water to constant volume.
2) Preparation of soil mixed standard solution: use 1mL straw to absorb 1.0mL soil nutrient mixed standard stock solution, put it in 100mL volumetric flask, and then use soil extractant to adjust the volume to the scale to obtain NH+4-N2.4 μ g/ml and NO-3-N2.4 μ g/ml.
2. Preparation of soil nutrient solution to be tested
Weigh 2.0g of air-dried soil sample or 2.0g of fresh soil sample (1+ water content), put it into a soil leaching bottle (triangular bottle or plastic bottle), suck 40ml of soil extractant into the leaching bottle with a straw, then pour a spoonful of soil decolorizer (about 0.5g) into the leaching bottle, keep the temperature at 20-25℃ and shake violently for 3min.
[Note 1] The frequency and intensity of oscillation in extraction have great influence on the reproducibility of the determination results, so it is recommended to use the recommended oscillator.
[Note 2] The filtered solution to be tested should be covered at any time and determined as soon as possible. It is not advisable to leave it for a long time, otherwise it will easily cause ammonium nitrogen loss.
[Note 3] The ambient temperature has a certain influence on the determination, especially on phosphorus. When the room temperature is lower than 20-25℃, it is suggested to preheat the soil extract to 30℃ for later use. (the same below)
Rapid soil nutrient analyzer
3. Determination of Nitrogen, Phosphorus and Potassium in Soil
Use a straw to take 2mL of soil extractant as a blank in a small reaction bottle, 2mL of soil standard solution (containing 2.4μg/mL of ammonium nitrogen) in another small reaction bottle, 2mL of soil solution to be tested in a third small reaction bottle, and add them in turn:
4 drops of soil ammonium nitrogen 1 reagent and 4 drops of soil ammonium nitrogen 2 reagent.
4 drops of soil ammonium nitrogen No.3 reagent and 2 drops of soil ammonium nitrogen No.4 reagent.
Shake well, after 10 minutes, transfer to a cuvette for determination:
① Press "Mode" key to switch the function number to 4, press "Adjust+" or "Adjust-" key to make the blue light source indicator light, put blank liquid in the light path, press "Mode" key to switch the function number to 1, and press "Adjust+" key to make the LCD display ≤100%; Press the "Adjust-"key to make the LCD display 100%.
② Press the "Mode" key to switch the function number to 3, put the standard solution into the optical path, and press the adjustment key to make the LCD display value 48.0.
③ Place the liquid to be measured in the light path, and the displayed reading is the content of ammonium nitrogen in the soil (mg/kg).
Note that the detection methods of available phosphorus and available potassium are the same as above.