To accurately predict the yield of tobacco in Shaoyang,soil samples from 70 tobacco growing areas were taken as the research objects.Firstly,the principal component analysis(PCA)was used to analyze the impact of 19 soil nutrient indexes on tobacco yield.The results showed that the yield of tobacco in Shaoyang was mainly affected by 9 soil nutrient indexes,including organic matter,available zinc,available boron,available manganese,available sulfur,exchangeable calcium,total potassium,available iron and available potassium.After that,support vector regression(SVR)was used to predict the tobacco ...