Correlation and regression analysis of the influence of economic factors on wheat yield

Abstract

The article presents the results of econometric modeling of wheat yield based on microdata from reports on the financial and economic status of agricultural producers. The relationship between wheat yield and economic factors is studied: indicators of the level of intensity (costs of mineral fertilizers, cost of fixed assets, direct labor costs for grain production, number of workers employed in agriculture per unit area) and specialization of agricultural production (proportion of revenue from sales of crop products in revenue from sales of agricultural products). Using the stepwise variable selection approach, statistically significant linear regression models were constructed that can be used for analysis and forecasting. The paired model included the cost of mineral fertilizers per 1 ha of sown area as a factor in wheat yield (coefficient of determination R2 = 0.503), and multiple regression was obtained by adding a second factor — the cost of fixed assets per 100 ha of agricultural land (multiple coefficient of determination R2 = 0.562). Decomposition of the multiple coefficient of determination into separate coefficients of determination allowed us to estimate the impact of each factor included in the model on yield: thus, the impact of mineral fertilizer costs was 42 %, and the impact of fixed assets was 15 %. According to the approach to decomposition of R2 based on β-coefficients, the net impact of mineral fertilizer costs on wheat yield was 35 %, the net impact of fixed assets was 5 %, while the impact of the systemic effect from the interaction of the two factors, which reflects the level of production intensification, was 17 %. Based on a multiple regression model, forecast values were constructed and estimated, and reserves for yield growth were determined.