Investigating the spatial patterns of potato yields variation in Polissia and Forest-Steppe zones of Ukraine

Abstract

This paper is aimed at establishing the regularities of the spatial-temporal variability of potato yield in Polissia and Forest-Steppe zones of Ukraine and determining the correlation between the dynamics factors of agro-economic and agro-ecological nature.

Methods of research. The regularities of spatial heterogeneity of potato yield on the territory of 267 administrative districts of Ukraine for over 27 years were studied using the principal component analysis (PCA). The statistical analysis was conducted using the Statistica 10 software product, as well as REdaS library for the statistical calculations in R Programming Environment.

The research results. Principal components analysis of the time trend model residues enabled to establish three aspects of potato yield variability within the studied area, or the principal components. Taken together, these three principal components explain 43.1% of the overall potato yields variability. The variables used in the PCA are the ordinal quantities – the years, so the loadings of the principal components on the variables can be represented as dynamic changes in time. Therefore, the principal components of oscillatory patterns reflect the specific variation patterns of potato yield in time, and these patterns are spatially defined. These oscillatory processes are of ecological origin. Concerning the dynamic aspect, these principal components are determined by different frequency characteristics of variation in time. Based on the character of the variation, we made the assumptions about the nature of the given principal components.

 Scientific novelty. It was for the first time that the PCA was used for studying the data concerning potato yields, and the factors that determined yields variability were identified.

Practical significance. Maps of the spatial variation of principal components can be the basis for agro-ecological zoning of the territory.