soil pH tester

First, overview of soil pH tester

Soil pH tester is an instrument used to detect soil pH value, which has a wide range of applications in agriculture, horticulture and other fields, and can help people understand the acid and alkali degree of soil, so as to provide a basis for planting suitable crops and soil improvement.

Second, the working principle of soil pH tester

(1) Electrochemical principles

Principle and mechanism

Soil pH testers usually use glass or electrochemical sensors to measure the concentration of hydrogen ions in soil solutions. These sensors contain a glass or metal film that is coated with an induction agent. When the inductor comes into contact with hydrogen ions in the soil solution, it causes a chemical reaction on the sensor surface. This reaction creates an electric charge whose magnitude is proportional to the concentration of hydrogen ions in the soil solution. The sensor measures this charge and converts it into a corresponding electrical signal, which gives the pH value of the soil.

(2) Principle of color indicator

Principle and mechanism

Color indicator is a substance that can produce color changes according to the acidity and alkalinity of the solution. When the concentration of hydrogen ions in the soil solution changes, the color indicator changes the color of its solution accordingly. A soil pH tester uses an optical sensor to measure the color of a color indicator solution and determine the pH of the soil based on the change in color.

Three, the soil pH tester components

(1) Sensors

Feature

The sensor is a key part of the soil pH tester, whether based on the electrochemical principle or the color indicator principle, the sensor must be able to accurately measure the concentration of hydrogen ions in the soil solution or the color change. For example, in a tester using the principle of electrochemistry, the sensor on the glass or metal film of the sensor should be able to effectively react with hydrogen ions to produce measurable charges; In the tester based on the principle of color indicator, the sensor should be able to accurately detect the color change of the color indicator.

(2) Measuring devices

Feature

The measuring device needs to be able to convert the data measured by the sensor (such as data related to charge or color change) into the corresponding pH value. The conversion method and accuracy of the measuring device vary between different types of testers to ensure that the final pH value can accurately reflect the acid-base degree of the soil.

Fourth, the use of soil pH tester

(1) General steps

Preparatory work

To prepare the soil pH tester and related reagents, generally including the testing instrument itself, the soil hoe, the sample container, the distilled water for wetting the soil, the pH reagent and the test liquid powder.

sampling

Sample the soil that needs to be tested, generally select the soil of different depths and different locations, and take a small part after mixing evenly. Then wait 10 minutes to half an hour for the short-acting substances in the sample to fully dissolve in the water.

measure

Turn on the test instrument and place the measuring electrode in the soil sample in the container (different instruments may be placed in different ways, and some can be inserted directly into the soil for testing). After waiting a few seconds, the instrument will automatically read and display the soil pH value. If precise testing is required, pH reagents and test liquid powders can be used.

Record and analyze the results

According to the display results of the instrument, the pH value of the soil is recorded, and the pH value of the soil is analyzed according to the measured soil pH value, the suitability of the soil is assessed, and the corresponding measures are taken to adjust. At the same time, it should be noted that different soil pH testers may have different methods of use and operating steps, and should carefully read the instructions of the instrument before use, and follow the instructions to operate.