Objective The aim was to understand and master the evolution characteristics of total nitrogen (N) content in cultivated land in Guangdong Province since the 1980s.

Method The long-term monitoring data of cultivated land quality in Guangdong Province since 1984 were used to analyze the changing trends of total N in cultivated soils over the past 37 years.

Result The results showed that the total N contents of cultivated soils in the province has shown an overall increasing trend since 1984, increasing from 1.42 g kg⁻¹ in the early stage of China's Seventh Five Year Plan for National Economic and Social Development (hereinafter referred to as "The 7^th Five Year Plan", 1986 ~ 1990) to 1.64 g kg⁻¹ during "The 13^th Five Year Plan" (2016 ~ 2020), with an increase of 15.5%. The total N has been raised by one level, mainly distributed in the 2^nd and 3^rd frequency levels. The 2^nd and 3^rd frequency levels showed a slow downward trend overall, from 74.0% before "The 7^th Five Year Plan" to 59.5% during "The 13^th Five Year Plan". The 1^st frequency level showed an overall upward trend, while the 4^th and 5^th frequency levels showed little change. The soil total N contents of cultivated land in the eastern, western, northern and Pearl River Delta regions of the province showed an overall increasing trend, with little difference in soil total N contents among different regions.

Conclusion The increase in fertilization and nitrogen fertilizer input, as well as field management measures such as high standard farmland construction, and adjustment of planting structure, are important factors that have led to an increase in total N content in arable soil throughout the Guangdong Province.