Abstract:The analysis of soil nutrient indexes in 371 tobaccogrowing areas in Youyang County,Chongqing in 2021 were conducted,longitudinally compared with the data in 2002,2012 and 2017.The current situation and evolution trend of soil nutrients in the tobaccogrowing areas of the county were analyzed,and scientific and reasonable fertilization suggestions were put forward according to local conditions.The results showed that the average mass fractions of soil organic matter,alkalihydrolyzed nitrogen,available phosphorus and available potassium were 22.6 g/kg,133.98 mg/kg,41.42 mg/kg and 328.52 mg/kg,with the proportion of 57.2%,77.1%,27.5% and 16.7%,respectively.Judging from the current situation of soil nutrients in tobacco fields,the soil organic matter content of tobacco fields was moderate,the supply capacity of alkalihydrolyzed nitrogen was good,and the contents of available phosphorus and available potassium were generally high.Compared with 2017,the soil pH value of tobacco fields were not changed significantly in 2021,and 26.4% of tobacco fields still need to be improved.The average mass fractions of soil organic matter and alkali hydrolyzable nitrogen decreased by 19.3% and 4.8%,respectively,and the average content of available phosphorus and available potassium increased by 2.0% and 17.7%,respectively.Therefore,the tobaccoplanting areas of Youyang County,Chongqing should take measures of "reducing acid,stabilizing nitrogen and organic matter,and controlling phosphorus and potassium".Based on the principle of soil testing and formula fertilization,the formula fertilization zoning map should be established,and the nutrient management strategies of "regional large formula" and "small plot adjustment" are adopted to achieve the synergistic improvement of tobacco leaf quality and soil quality.