Soil pH is one of the most important basic properties of soil. The availability of essential nutrients for most crops is related to the pH of the soil. Therefore, understanding the pH status of soil is important for understanding the effectiveness of soil nutrients and recommending fertilization. . While measuring soil nutrients, soil pH measurement is also an indispensable indicator. First, the principle of the method Soil pH measurement methods can be roughly divided into potential and colorimetric methods. With the development of analytical instruments, soil laboratories have basically adopted the potentiometric method, and potentiometric methods have the advantages of accuracy, speed, and convenience. The potentiometric method is used in the ASI method. The basic principle is that when a pH meter is used to measure the pH of the soil suspension, the potential difference is generated due to the difference in the activity of the solution H+ ion inside and outside the glass electrode, that is: Where: a1 is the H+ ion activity of the solution in the glass electrode, and the value is fixed. A2 is the H+ ion activity of the solution outside the glass electrode, ie the activity of H+ in the solution to be tested. It can be seen from the above equation that the potential difference between the inside and outside of the glass electrode is determined only by the activity of H+ in the test solution, and the negative logarithm value is the pH. The pH of the solution can be read directly from the pH meter by switching on the pH meter. Second, reagent preparation 1. pH 4.01 Standard Buffer Solution Weigh 10.21 g of potassium hydrogen phthalate (KHC8H4O4, analytical grade) dried at 105°C in a 1000 ml volumetric flask and dissolve to volume after dissolution. 2. pH6.87 Standard Buffer Solution Weigh 3.39g of potassium dihydrogen phosphate (KH2PO4, analytical grade) dried at 50°C in a 1000ml volumetric flask, and dissolve to volume after dissolution. 3. pH9.18 Standard Buffer Solution Weigh 3.39 g of borax (Na2B4O7•10H2O, analytical grade) in a 1000 ml volumetric flask and dissolve to volume after dissolution. Third, the operation steps (I) Instrument calibration To check the pH with a standard buffer, two different pH buffers must be used, one at pH 4.01, one at pH 6.87, or one at pH 6.87 and one at pH 9.18 depending on the pH of the soil It is appropriate to approach this pH of the soil. During the test, first insert the electrode into a buffer, turn on the power, after adjusting the zero point and temperature compensation, set the baffle to the pH level and use the “positioning†adjustment knob to adjust the reading to the pH of the standard buffer. This time the adjustment is Electrode asymmetric potential, after a buffer correction, if the electrode is intact or the instrument has been working under normal conditions, the allowable deviation should be within 0.02 (pH 7.00±0.02) when checking with the second buffer. If there is a large deviation, the electrodes must be replaced and the instrument must be checked. (b) Determination of soil pH 10 ml of the soil sample was placed in the sample cup and 25 ml of boiled cooled pure water was added with the extract dispenser, stirred for 10 minutes on a blender, allowed to stand for 30 minutes, and then the pH was measured with a pH meter. Reading the reading directly is the soil pH. Intertech is a leading supplier for Caps And Closures Mold,Bottle Cap Injection Mold,making all kinds of custom plastic containers and plastic storage boxes mold and plastic container mould in Taiwan. Intertech's services include prototyping, tooling, lab testing, production and assembly.Intertech has abundant experience in manufacturing plastic container mould since its establishment in 1987. We provide plastic container mould. We are a customer-focused company, hence we take our customer`s requirements very seriously. Caps And Closures Mold,Mold In Water Bottle Cap,Bottle Cap Injection Moulding Machine,Bottle Cap Injection Mold Intertech Machinery Inc. , https://www.taiwanmouldmaker.com