At present, many production units in China use a formula reagent provided by Professor Zhu Haizhou of the late Chinese Academy of Agricultural Sciences. However, due to the lack of patent application, the counterfeit formulas have appeared one after another, resulting in a large number of disorderly competition. After so many years of practice, the original reagent formula has different degrees of loopholes. Some enterprises have timely repaired and corrected according to their own exploration and user feedback information, such as the air-drying treatment of the previous soil samples. It is a pity that many companies have not realized that there are many errors or obvious errors in the post-testing process, which makes the road of promotion that is not so smooth is even more thorny.
Photoelectric colorimetric agents are not unique, but from the perspective of instrument operation, they can only be favored by farmers for the sake of farmers. For example, from the reading point of view, the lowest grade product of the soil nutrient rapid tester can also read the number of kilograms per acre. This value was called PPm (ie, mg/kg). It is only necessary to test a dilution factor to obtain a kilogram per acre. For the farmers, the operation is more troublesome.
In addition, the intelligent Chinese character guiding type is an early multi-functional soil measuring instrument that can measure the nitrogen, phosphorus, potassium, organic matter and humic acid content in the soil. The salt test can read the percentage directly from the small screen, and the previous method is to use a computer rate coordinate graph for analysis and conversion is very cumbersome.
But not all test data is directly read out in Chinese. For example, the concentration of NPK is still marked by PPm. It is in line with international standards. In addition, there is a formula function in the later stage, which can directly output the recommended fertilization scheme for 67 crops. The reason why the proposal is more cautious. Because any kind of solution is absolutely perfect. If your instrument is universal, it is irresponsible. Can only be adjusted continuously.
Simply selecting an instrument is easier. The technology used in the rapid measurement is NPK photo-electrical colorimetry. If it is different, it is more portable, stable, reproducible and easy to operate. However, there are two of the most essential issues that must be considered.
The first question is whether to warm up after booting. Because if the warm-up time is too long, for example, it takes more than half an hour in the field to take up to 20 minutes. It is very inconvenient for the user. From the perspective of energy, r is also wasteful.
The second question is whether the use of red or green light in the selection of the light source will directly affect the accuracy of the later test results. With the light source inside the instrument - photoelectric colorimetric agent, a visible light band between 420 nanometers and 1000 nanometers can be obtained. The soil tester uses one of the two wavelength bands, one of the center wavelengths 440, and one of the center wavelengths is red light, and red and blue light can be selected based on the two data. The indicators in the laboratory are nitrogen 650, phosphorus 670, and organic matter 620.
All three of these red light ranges can be measured with red light. Nowadays, many manufacturers produce instruments that use green light as a light source when measuring nitrogen. In fact, you should use red light. Why use red light to test it? According to the complementary principle of photoelectricity, blue absorbs red light, and white light and yellow light absorb blue light. According to this principle, if the soil liquid to be tested is blue, then the red should be selected for testing. The principle is the same as the red, yellow and blue primary colors. Finally, according to the different colors and extents of the liquid after the change of light intensity, the content of various elements such as nitrogen, phosphorus and potassium in the soil liquid is judged.
If the green light is used to test that the liquid to be tested is pure blue, the final data is acceptable. However, in the actual test, the liquid to be tested is often not so pure, and the photoelectric complementarity between green and blue light is not so strong, so that the final detection data is Not very accurate. So red light is obviously more suitable.
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