Onions, essential in various salads and cooked dishes, are sought after by producers for high yields, while consumers value their quality, particularly the presence of antioxidant compounds. This study investigates the impact of production methods and biostimulants on the biomass yield and quality of onions. The two-year experiment was conducted in Vojvodina, Serbia, and compared directly seeded (DS) and from-set (FS) onions with four biostimulant treatments: control (C), seaweed extracts (T1), humic and fulvic acids (T2), and Trichoderma sp. (T3). DS onions yielded significantly more biomass, while FS onions had higher dry matter content. DS onions treated with T1 showed a significant increase in phenols (↑ 5.30%), while T2 and T3 led to declines (↓ 8.66% and ↓ 7.55%, respectively). All biostimulants reduced phenol content in FS onions. T1 and T2 significantly increased the flavonoid concentration in DS onions, with no significant changes in FS onions. T1 enhanced antioxidant properties in DS onions and reduced them in FS onions. Additionally, T2 and T3 decreased antioxidant activity in both DS and FS onions, as evidenced by DPPH, FRAP, and ABTS tests. These findings guide onion production, advocating for the fresh consumption of DS onions with higher biomass and industrial processing suitability for FS onions, emphasizing the potential of bio-based products.

In the pursuit of maximizing onion (Allium cepa) yield and quality, farmers often face the challenges of unfavorable ecological conditions and inadequate agronomic practices. Therefore, our two-year study investigated the effects of biostimulants (BTs) of plant growth on bulb yield and the bioactive compounds of directly seeded onion. Four treatments were applied: control (C), seaweed extracts (BT1), humic and fulvic acid (BT2), and Trichoderma spp. (BT3). The results demonstrated a significant increase in bulb yield with BT1 (↑ 18.7%), BT2 (↑ 18.0%), and BT3 (↑ 24.3%). Intriguingly, all BTs markedly reduced phenolic content across both years. Additionally, BT1 and BT3 elevated flavonoid levels (↑ 16.8% and ↑ 16.7%, respectively), while BT2 decreased them (↓ 24.2%). Notably, in 2021, DPPH, FRAP, and ABTS tests indicated a significant reduction in antioxidant capacity compared to C. Our study underscores the important role of BTs in enhancing yield, influencing secondary metabolites and contributing to environmental sustainability in onion cultivation.

Potatoes are essential for chip production, requiring high quality for processors and high yields for farmers. This two-year study was carried out for the purpose of investigating the influence of irrigation, fertilization, and cultivar on potato yield and tuber and chip quality. Field experiments were conducted in Sombor, Serbia, using a split-split plot design with three replications. Whole-plot treatments involved two irrigation schemes: sprinkler irrigation (SI) used as standard (control) and drip irrigation (DI). Subplot treatments included nitrogen (N) and potassium (K) fertilization in four different combinations: 64 kg N/ha and 64 kg K/ha (N₆₄K₆₄) as control; 77 kg N/ha and 110 kg K/ha (N₇₇K₁₁₀); 90 kg N/ha and 156 kg K/ha (N₉₀K₁₅₆); and 103 kg N/ha and 202 kg K/ha (N₁₀₃K₂₀₂). Sub-subplots comprised three cultivars: VR-808; Pirol; and Brooke. The VR-808 cultivar consistently yielded the highest amount (25.6 and 24.9 t/ha) under both irrigation methods. DI raised tuber flesh temperature compared to SI. The N₉₀K₁₅₆ × Pirol interaction exhibited the highest number of tubers with defects, while N₉₀K₁₅₆ × VR-808 had the fewest. Under DI, the VR-808 cultivar produced chips with the highest total defects, whereas Brooke had the lowest. The postfrying palm oil temperature was the highest for N₆₄N₆₄ × Brooke and the lowest for N₁₁₀K₂₂₀ × Pirol. This study underscores the role of irrigation, fertilization, and cultivar in achieving high yields and high chip quality, providing valuable insights into the whole process, from field to chip bag.