Research Progress on the Nitrogenous Fertilizer in China based on the Bibliometric Method by Citespace

In this article, the data mining and quantitative analysis were carried out with the subject terms of 'nitrogen' by Citespace software and CNKI, by searching 16081 papers between 1996 and 2016, it also showed the theme, content and development tendency of the research field of nitrogen application. The research results showed that: 1) The study of nitrogen fertilizer has experienced three periods: The first stage from 1996 to 2000, the hot research was suitable quantity nitrogen usage and nitrogen form on a variety of crops; and the second stage is from 2000 to 2010,the research focus on prescription fertilization and nitrogen use efficiency; and the third stage is from 2010 to 2016, the hot research was cutting back on nitrogen fertilizers and increasing crop yield.2) The content of the nitrogen fertilizer research in China is mainly for food crops, and less research on economic crops.