Optimization of nitrogen, phosphorus, and potassium fertilizationfor maximizing root yield and inulin yield in chicory (Cichorium intybus L.)

B. Mazurenko*, L. Honchar, A. Yunyk, R. Kovalenko, O. Shutyi and S. Kalenska

Department Plant Science, National University of Life and Environmental Sciences of Ukraine, Heroiv Oborony Str., 15, UA03041 Kyiv, Ukraine
*Correspondence: mazurenko.bohdan@nubip.edu.ua

Abstract:

Root chicory (Cichorium intybus L.) is an important industrial crop for inulin production, but the optimization of mineral fertilization under fertile chernozem soils remains insufficiently defined. Under such conditions, additional fertilizer inputs may not proportionally increase root and inulin yield and may lead to higher residual nutrient levels after harvest. The aim of this study was to evaluate the effects of nitrogen and phosphorus-potassium fertilization on root biomass traits, crude inulin content, inulin yield, and post-harvest soil nutrient status of root chicory grown in the Right-Bank Forest-Steppe of Ukraine. A three-year field experiment (2021–2023) was conducted using a two-factor design with incremental PK and N rates. Cluster analysis and pairwise correlation coefficients were calculated between these parameters. The proposed approach to determining the optimal fertilizer rates for maximizing yield in individual years indicated values of N₁₃₀P₆₆K₁₁₀, N₁₅₀P₆₀K₁₀₀, and N₁₂₀P₇₂K₁₂₀, with an average of N₁₃₀P₆₆K₁₁₀. The highest inulin yield reached 5.80 t ha⁻¹, compared with 2.88 t ha⁻¹ in the unfertilized control. Crude inulin concentration varied less than biomass-related traits, indicating that industrial raw material output depended primarily on root productivity rather than on large changes in inulin concentration alone. Post-harvest soil analysis showed that nitrogen fertilization increased residual hydrolysable nitrogen, whereas PK fertilization mainly increased mobile phosphorus at higher application rates. Thus, optimization of chicory fertilization under fertile chernozem conditions should be considered not only as a strategy for maximizing root and inulin yield, but a way to improve nutrient-use efficiency and avoid unnecessary nutrient surpluses.

Key words:

Agro-ecology, cluster, correlation, model, nutrient

The effect of mulching and pruning on the vegetative growth and yield of the half-high blueberry

T. Albert¹, K. Karp¹, M. Starast¹ and T. Paal²

¹Estonian University of Life Sciences, Institute of Agricultural and Environmental
Sciences , Kreutzwaldi 1A, 51014 Tartu, Estonia
²Estonian University of Life Sciences, Institute of Forestry and Rural Engineering,
Kreutzwaldi 1A, 51014 Tartu, Estonia, e- mail: tairi.albert@emu.ee

Abstract:

The aim of this research was to determine the influence of different mulches (peat, sawdust, plastic) and different pruning methods (moderate, severe) on the growth and yield of the half–high blueberry (Vaccinium corymbosum x Vaccinium angustifolium) ´Northblue´. The effect of a mixture of soil and peat was studied in the case of peat alone and peat and plastic mulches. The experiment was established in 1996 in South Estonia and in 2002 blueberry bushes were pruned. The results of the study showed that mulching significantly influenced nutrient content and pH. Depending on the mulch, the soil pH ranged from 4.5 to 6.1 – there was more acid soil in the peat treatment. The use of mulches had some influence on productivity of pruned half-high blueberry plants. When peat was applied a canopy of pruned plants recovered very well after one year. Within three years the plants had the same yield as un-pruned variants but four years after pruning the yield was highest in the variants where peat was applied. Plastic mulch is not suitable for blueberries: it decreases the yield and four years after pruning the normal plant growth in our study had not recovered. Severe pruning is more suitable for half-high blueberry fruiting plants in northern climate conditions.

Key words: