Agroecological and agroeconomic aspects of the grain and grain legumes (pulses) yield dynamic within the Dnipropetrovsk region (period 1966–2016)

This paper reveals the spatial and temporal patterns of grain and leguminous crops yield dynamics in Dnipropetrovsk region and evaluates the role of agro-environmental and agro-economic factors in their formation. Crop data were obtained from the State Statistics Service of Ukraine. The data of the grain and grain legumes (pulses) yield during 1966–2016 on average per year in the administrative districts of Dnipropetrovsk region was analysed. The obtained data indicate that average yields of cereals and leguminous crops within Dnipropetrovsk region varies from 24.3 to 33.4 CWT/ha.
The smallest interannual variability in yield is typical for Vasylkivskyi district (CV = 9.9%), and the largest is typical for Yurivskyi district (CV = 27.7%). As a result of the principal component analysis of the cereals and leguminous crops
yields variability, three principal components were extracted which together explain 81.2% of the overall yield variability. Principal component 1 explains 69.4% of the total variability. It indicates the total synchronous yields variation within the area investigated as all examined variables have high loading values on principal component 1. The administrative districts that form a belt located in the direction from the north east to the south west of the region have the most coordinated variance, which is reflected by principal component 1. Principal component 2 explains 6.8% of the yield
variability. This principal component is sensitive to opposite yield dynamics of central and south-western districts on the one hand and the eastern and northern districts – on the other. Principal component 3 explains 4.9% of the yield variability. This principal component reveals the opposite dynamics of productivity of the central districts on the one hand and the northern and south-eastern districts on the other. The cluster analysis of administrative districts was conducted
based on the dynamics of the yield of grain and leguminous as a result of which four clusters were identified. The clusters are geographically defined administrative districts, together forming spatially connected areas. The similar temporal yield dynamics of grain and leguminous crops as a result of interaction between endogenous and exogenous ecological factors
is the main principle for revealling such ecologically homogeneous territories. Spatial distribution of principal components indicates a continual pattern, but their overlapping allows one to extract spatially discrete units, which we identified as agroecological zones. Each zone is characterized by a certain character and dynamics of production capacity and has an
invariant pattern of response to varying climatic, environmental, and agroeconomic factors.
Keywords: agroecological factors; yield; grain; leguminous crops; spatial and temporal variability; principal components analysis