Sugar beet fertilization is a very complex agrotechnical measure for farmers. The main reason is that technological quality is equally important as sugar beet yield, but the increment of the root yield does not follow the root quality. Technological quality implies the concentration of sucrose in the root and the possibility of its extraction in the production of white table sugar. The great variability of agroecological factors that directly affect root yield and quality are possible good agrotechnics, primarily by minimizing fertilization. It should be considered that for sugar beet, the status of a single plant available nutrient in the soil is more important than the total amounts of nutrients in the soil. Soil analysis will show us the amount of free nutrients, the degree of soil acidity and the status of individual elements in the soil so that farmers can make a compensation plan. An estimate of the mineralizing ability of the soil, the N min, is very important in determining the amount of mineral nitrogen that the plant can absorb for high root yield and good technological quality. The amount of N needed by the sugar beet crop to be grown is an important factor, and it will always will be in the focus for the producers, especially from the aspect of trying to reduce the N input in agricultural production to preserve soils and their biodiversity but also to establish high yields and quality.

Soybean is generally grown as a rainfed crop worldwide and very often is exposed to drought and high temperatures. The objectives of this study were to determine the performance and stability of 32 elite soybean genotypes for seed protein and oil contents across six dry and eight normal environments and to determine the influence of environment on the relationship between the two traits. In the combined ANOVA, genotypes (G), environments (E) and G × E were significant for both traits with protein content being more sensitive to environmental changes than oil content. Mean seed protein content decreased by 4.5% under drought conditions compared to normal ones and ranged from 2.3% to 7.1% for individual genotypes. At the same time drought caused a slight increase in seed oil content of +1.2%, with a range of −1.3% to +4.5% for individual genotypes. Genotype stability in terms of regression coefficient (b) and coefficient of variation (CV) was in moderate to weak negative correlation with mean genotype performance for protein content, while no correlation was observed between genotype stability and mean genotype performance for oil content. Protein and oil content were significantly negatively correlated in normal environments (r = −0.33), while no correlation between the traits was observed in dry environments (r = −0.02).

Nitrogen fertilization greatly affects the development of sugar beet leaf and photosynthetic activity. This study aimed to evaluate the dynamics of leaf SPAD index, chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids (Caro), and the macronutrient status (N, P, K, Na, Mg) in different N fertilization rates in sugar beet production. This study set up a two-year field experiment in Eastern Croatia. The N fertilization rate was applied as: N0—control, N1—only presowing fertilization (45 kg/ha), and N2—presowing with topdressing (99 kg/ha in 2014 and 85.5 kg/ha in 2015). In general, N fertilization has a significant (p ≤ 0.05) influence on leaf pigments, except for Chl b. With the highest N dose (N2), the Chl content in the leaves increased by 12% compared to the control treatment (0.75 mg/g FW). The Caro dynamics in the leaves of vegetative growth were significantly different (p ≤ 0.05); leaves in the younger growth stage at the end of May had the highest Caro content (0.011 mg/g FW). In general, the SPAD index was significantly different (p ≤ 0.05), among N fertilization, whereas the lowest SPAD was found at the control treatment (38.7) and the highest at the N2 treatment (40.8). In general, regarding nitrogen fertilization, the lowest SPAD readings had sugar beet leaves at the control treatment (38.7), whereas the highest was determined at the N2 treatment (40.8). A strong positive relationship (p ≤ 0.01) was determined for Chl a, Chl b, Chl a + b, and Chl a + b/Caro with the SPAD index, whereas an inverse relationship with the SPAD index was determined for Caro and Chl a/b. The results demonstrate that nitrogen application, particularly at higher rates, positively influences chlorophyll and carotenoid content, as well as overall plant health, which can inform agricultural practices for more sustainable and efficient sugar beet cultivation.

Due to the increasing presence of industrial hemp (Cannabis sativa L.) and its multiple possibilities of use, the influence of different light and several biopreparations based on beneficial fungi and bacteria on hemp’s morphological and physiological properties were examined. Different biopreparations and their combinations were inoculated on hemp seed and/or substrate and grown under blue and white light. A completely randomized block design was conducted in four replications within 30 days. For biopreparation treatment, vesicular arbuscular mycorrhiza (VAM) in combination with Azotobacter chroococum and Trichoderma spp. were inoculated only on seed or both on seed and in the substrate. Generally, the highest morphological parameters (stem, root and plant length) were recorded on plants in white light and on treatment with applied Trichoderma spp., both on seed and substrate. Blue light negatively affected biopreparation treatments, resulting in lower values of all morphological parameters compared to control. Leaves pigments were higher under blue light, as compared to the white light. At the same time, 1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), flavonoids, total flavanol content and phenolic acids were not influenced by light type. Biopreparation treatments did not significantly influence the leaves’ pigments content (Chl a, Chl b and Car), nor the phenolic and flavanol content.

Industrial hemp, as a natural plant fiber, has received increased research attention recently. Potassium fertilization is one of the most important fertilizers for plant stem thickness, but how the formulation of K fertilizer influences stem morphology and stem tensile strength remains unclear. This study aims to examine the influence of K fertilizer sources on industrial hemp stem properties, with a specific focus on the fibers, to evaluate their potential applications as reinforcement material for stabilizing rammed earth in sustainable construction. A field experiment was set up with different K fertilizer types applied as pre-sowing fertilizer in the following doses: K₀—control, K₁—100 kg ha⁻¹ KCl, and K₂—100 kg ha⁻¹ K₂SO₄. Different K fertilizations did not have significant influence on stem height, which was on average 71.2 cm, nor on stem diameter, which was on average 3.4 mm. Regarding the macronutrient content of the industrial hemp stem (N, P, and K), K fertilization treatment significantly influenced (p < 0.05) their accumulation. The N, P, and K content in the stem within fertilization treatment averaged 0.78, 0.72, and 1.26%, respectively. The average content of cellulose, hemicellulose, and lignin was not significantly different in relation to K fertilization treatments. In the stem, dry weight cellulose content varied from 57.8% (K₀) to 59.0% (K₁), hemicellulose from 11.0% (K₂) to 11.6% (K₀ and K₁), and lignin from 10.2% (K₂) to 10.5% (K₀). The tensile strength and Young’s modulus of the industrial hemp stem were non-homogenous within K fertilization treatments. The highest tensile strength (388.52 MPa) and Young’s modulus (32.09 GPa) were on K₁ treatment. The lowest industrial hemp stem tensile strength was determined at K₂ treatment (95.16 MPa), whereas stems in the control treatment had the lowest Young’s modulus (21.09 GPa). In the mixtures of hemp fibers with rammed earth, the higher compressive strength was determined on cubic samples than on cylindrical samples. This study contributes to the industrial hemp K fertilization of the newer genotypes, but there has been a lack of research in recent times. Since industrial hemp has great potential in various industry branches, this study also contributes to using fiber extracted from the stem in eco-friendly and renewable forms in mixtures with rammed earth.

The growing interest in Cannabis sativa as a highly used crop is present worldwide. There are limited data about the effect of potassium (K) fertilizer on industrial hemp yield for dual purposes (seed and stem production). The current study aimed to investigate the influence of adding two different K fertilizers, KCl and K₂SO₄, at two growth stages (flowering and ripening) on the productivity and chlorophyll a fluorescence (ChlF) of Cannabis sativa, variety Finola. Before sowing, different K treatments were applied: K₁—100 kg ha⁻¹ KCl (60% K) and K₂—100 kg ha⁻¹ K₂SO₄ (52% K, S 17%). The OJIP (O stands for “origin” (minimal fluorescence), P for “peak” (maximum fluorescence), and J and I for inflection points between the O and P levels) data were recorded and used for ChlF transients and individual ChlF parameters during vegetation. At harvest, the stem morphology parameters and yield (plant height, stem weight and diameter, and stem and seed yield), tensile strength, and the modulus of elasticity were determined. The results show the sensitivity of minimal (F₀) and maximal fluorescence (F_m), electron transport from Q_A to intersystem electron acceptors (ET₀/(TR₀ − ET₀)), and electron transport flux until PSI acceptors (RE₀/RC) to K fertilization. The parameters that described electron transport (ET₀/RC, ψE_0, and φE₀), performance index on absorption basis (PI_ABS, TR₀/DI₀, and φP₀), dissipation (DI₀/RC), and electron transport to photosystem I (φR₀ and δR₀/(1 − δR₀)) had a reaction only at the growth stage, indicating a change in their activity during the aging of the Cannabis sativa plants. The average stem height was 67.5 cm, and the stem diameter was 0.41 cm. The different K sources did not significantly influence the stem height and diameter, nor the dry stem (on average 12.2 t ha⁻¹) and seed yield (on average 1.85 t ha⁻¹). The tensile strength of individual hemp stems was the highest with K₂SO₄ (53.32 MPa) and the lowest with KCl (49.25 MPa). The stem stiffness by modulus of elasticity was about 5 GPa on average for all the treatments. In general, the photosynthetic parameters in this study varied more between the growth stages than between the different K fertilizer formulations. Moreover, based on the results of this study, it can be recommended to use both fertilizers, KCl and K₂SO₄, in dual-purpose industrial hemp production since no significant effect was found for the stem morphometric and biomechanical parameters as well as for the agronomic parameters.