The article discusses territorial and structural changes in the productivity of grain and leguminous crops in the districts of the Republic of Belarus, as well as differences in the doses of mineral fertilisers for certain types from 2014 to 2018. The aim of the study is to determine the degree of influence of fertilisers on the dynamics of productivity for the studied period and to analyse the reasons for changes in the level of yields of grain and leguminous crops in the regions of the country. The work is based on statistical research methods – correlation and regression analysis of the relationship between mineral fertilisers and productivity were carried out. Correlation analysis showed a significant inverse linear dependence of the yield dynamics on the fertility score (correlation coefficient – 0.66), proving that more fertile soils lose in harvests of grain and leguminous crops are almost 2 times in comparison with less suitable land. Regression analysis confirmed the significant effect of mineral fertilisers (determination coefficient 56 %) on the final harvests of grain and leguminous crops. The novelty of the research lies in the mathematical formalisation of the stochastic dependence of the yield of grain and leguminous crops on the level of application of certain types of mineral fertilisers and the establishment of its linear character. With the help of GIS technologies, territorial differences in the effectiveness of the use of fertilisers for grain and leguminous crops in the administrative regions of the Republic of Belarus were established and three clusters of productivity in the country were identified – highly productive south-west (Grodno Region, Brest Region and adjacent districts of Minsk Region), productive south-east (Gomel Region and Mogilev Region with border areas of neighbouring regions) and low-productive north (Vitebsk Region with northern regions of Minsk Region and Grodno Region).