The spatio-temporal trend of rapeseed yields in Ukraine as a marker of agro-economic factors influence
¹Zhytomyr National Agroecological University, Faculty of Forestry, Department of Forest Resources Utilization, Stary Blvd, 7, UA10008Z Zhytomyr, Ukraine
²Bogdan Khmelnitsky Melitopol State Pedagogical University, Faculty of Chemistry and Biology, Botany and Horticulture Department, Hetmanska steet 20, UA72318 Melitopol, Ukraine
³Zhytomyr National Agroecological University, Faculty of Forestry, Department of Forest Ecology and Life Safety, Stary Blvd, 7. UA10008 Zhytomyr, Ukraine
⁴Zhytomyr National Agroecological University, Faculty of Ecology and Law, Department of Bioresources, Aquaculture and Natural Sciences, Stary Blvd, 7, UA10008 Zhytomyr, Ukraine
The paper demonstrates the applicability of several statistical methods to the analysis and interpretation of the average rapeseed yield data. It proves our hypothesis that the general trend of rapeseed yield variations in Ukraine during 1991–2017 occurred due to agro-economic and agro-technological factors, which are the determinants of the revealed general trend. The temporal trend of rapeseed yield in most administrative districts can be described by a fourth-degree polynomial, namely, its characteristic points enabled us to describe and interpret the dynamics of rapeseed yields. The absolute term of the polynomial shows the initial conditions of the process, and its mapping allows us to identify the areas with the most favorable soil-climatic conditions for the rapeseed cultivation. Indicators of the maximum rate of growth and decrease of yields are the markers of stability of agro-ecosystems to the external influences. Therefore, the mapping of the maximum rate of decline and increase of yields reveal areas in which yields respond rapidly (increasing / falling) to the changes in agro-economic and agro-technological conditions, as well as areas where yields are more stable and change gradually. Thus, the form of the yield trend is determined by the influence of agro-technological and agro-economic factors, whose contribution to the fluctuation in rapeseed yields varies from 53% to 90%.