The article deals with the description of the creating method for a predictive model of the nitrogen supply and the comparison of the obtained predictive models based on different vegetative indices. The predictive models for plants of the «Protva» bean species of Russian selection at various concentrations of total nitrogen in the soil are presented in the article. All models were obtained on the basis of comparative analysis of various vegetative indices. The authors propose to use the obtained predictive model for determining current concentration of nitrogen in the soil. Such information can be used for creating soil maps of a field with a high spatial resolution, which are successfully used to apply fertilizers in precision farming systems and can significantly improve productivity and yield.