Structural Concentration and Diversification of Selected Crops in Kazakhstan: A Volume-Based Multi-Indicator Analysis

This study examines long-term changes in the volume-based production structure of a balanced basket of 19 crops in Kazakhstan from 2000 to 2024. Annual FAOSTAT production volumes were used to calculate the Herfindahl–Hirschman Index (HHI), Diversification Index, Shannon Entropy Index and Top-3 Crop Share. Direction and magnitude of change were assessed using the Mann–Kendall trend test and Theil–Sen slope, while crop-specific changes and a no-wheat sensitivity analysis were used to evaluate the composition of diversification. Selected World Development Indicators were examined in supplementary trend-adjusted regressions with Newey–West heteroskedasticity- and autocorrelation-consistent standard errors. HHI declined from 0.416 in 2000 to 0.329 in 2024; Kendall’s τ was −0.613 (p < 0.001), with a Theil–Sen slope of −0.0067 per year. Shannon entropy increased and the Top-3 Crop Share decreased. Wheat remained dominant, although its share fell from 0.623 to 0.550, while sunflower seed, linseed, sugar beet and maize increased their shares. Volume-based diversification remained statistically evident after wheat was excluded. Once a deterministic time trend was included, none of the macroeconomic coefficients was robust across specifications; the negative trend remained significant. The study contributes by distinguishing structural concentration across crops from firm-level market concentration and by providing a transparent multi-indicator assessment of a selected crop basket in a resource-dependent post-Soviet economy.