The result of pot experiment displayed that the releasing ratio of the new fixed NH + 4 of overburden layer and loess parent material horizon in Lou soil was 98.32% and 95.09% respectively.

• 盆栽试验结果表明 :土娄土覆盖层和黄土母质层中“新”固定态铵的释放率分别为 98.；32%25和 95