Soil hydrolyzable nitrogen, also known as soil availability nitrogen, is the sum of ammonium nitrogen, nitrate nitrogen, amino acids, amides, and readily hydrolyzable protein nitrogen. It is an important part of soil nitrogen and can better reflect the soil in the near future. The supply status of N plays an important role in measuring the level of soil nitrogen supply. The widely used methods for the determination of soil hydrolyzable nitrogen mainly include diffusion absorption method and alkali hydrolysis distillation method. The diffusion method for the determination of soil hydrolyzable nitrogen is a commonly used laboratory analysis method. The principle is to use a sealed diffusion vessel. 1mol/L sodium hydroxide solution hydrolyzes the soil sample, converts the available nitrogen to alkaline solution under constant temperature, and continuously diffuses and escapes. It is absorbed by boric acid (H3BO3) and titrated with standard hydrochloric acid to calculate soil hydrolysis. The content of nitrogen. The nitrate nitrogen content in dryland soils is higher, and zinc powder and ferrous sulfate are added to reduce it to ammonium nitrogen. The advantage of this method is that it is simple to operate and is suitable for large-scale detection; the disadvantage is that the detection takes a long time, a batch of samples takes about 26 hours, and a large-scale constant temperature device is also needed. Moreover, defects inherent in the experimental operation can easily lead to erroneous experimental results. For example, boric acid and sodium hydroxide in the diffusion plate are prone to mutual contamination; if the glass plate cannot be completely sealed with the diffusion plate, ammonia gas escapes and the result is low. . press fittings produces accorindg to park ,connex ,vigea and nibco,Approved watermark Press Fittings，press fittings，vigea press fittings，Nibco press fittings Taizhou Runde Company , https://www.zjbrassfittings.com
The principle of alkaline hydrolysis distillation is to hydrolyze soil samples with 40% NaOH in a distillation unit to convert alkali nitrogen from available nitrogen into ammonia nitrogen and to escape from the alkali solution in the form of ammonia. Boronic acid is used to absorb the standard sample. Acid titration to calculate the amount of hydrolyzed nitrogen. The conventional laboratory can provide measurement results in only 2 hours, which greatly improves work efficiency and is suitable for rapid analysis of a large number of samples. In recent years, more and more experts and scholars have also accepted the accuracy and accuracy of alkaline hydrolysis distillation method to determine soil nitrogen hydrolysis.
The method of YN series soil nutrient measuring instrument to measure the hydrolysis of nitrogen is improved from the alkaline hydrolysis method. The principle of the two is the same. It only simplifies the distillation absorption device and shortens the distillation time. The absorbed ammonia is not a standard acid. Titration, but measured by Nessler's colorimetry. Since all of the chemicals used are finished products, it is only necessary to add them according to the number of drops, which greatly shortens the detection time. It takes only about 45 minutes to detect one sample. And it also reduces equipment costs, and is more practical in basic soil nutrient differentiation tests than the conventional laboratory alkaline diffusion method.