【摘要】 <正> J.M.Bremner运用Conway所提出的微量扩散法成功地測定了土壤中的氨态氮及硝态氮。条件試驗証明氨态氮及硝态氮的平均回收率分別可达99.2%及99.9%。扩散法有很多优点。需要的設备极簡单,所用試剂也都是通常容易获得的,而且試剂的用量更多还原

【Abstract】 The determination of mineral nitrogen in soils has been successively done by Conway’s diffusion method. Owing to the high content of ammonical nitrogen present in most manures, and also to the turbidity of their extracts, this method fails to give good duplicates in ammonia determination from separated aliquots. The present article gives a modified technique of Conway’s procedure for the extraction and determination of ammonical nitrogen in manures with percentage recovery ranging 97.2—104%.5 grams of sample are extracted by a 10% KCl-0.1N HC1 solution with sampleextractant ratio from 1:10 to 1:20 or even wider in case of manures with exceedingly high content of ammonical nitrogen. A 2 ml aliquot, containing NH₄-N<100γ is used for analysis. The distillation of NH₄-N can be completed in 24 hrs by MgO displacement in Conway’s dish at room temperature.更多还原