NY/T 1121.24-2012 "Soil Testing. Part 24: Determination of Total Soil Nitrogen. Automatic Nitrogen Determination Method" specifies the method for determining the total nitrogen content of soil using an automatic nitrogen determination instrument. This standard applies to the accurate determination of total nitrogen content in soil. The method involves the oxidation of nitrite nitrogen in the sample to nitrate nitrogen, and then the reduction to ammonium nitrogen with reduced iron powder. After high temperature analysis, distillation, absorption and titration are carried out. The automatic nitrogen determination instrument realizes the automation of distillation, titration and result calculation. The standard cites a number of relevant documents, such as GB/T 601 and GB/T 6682, which cover standards such as chemical reagent preparation and laboratory water specifications.