Abstract
The study evaluated the effects of foliar application of an Artemisia absinthium L. aqueous extract and a formulation containing biosynthesized iron nanoparticles (FeNPs) on the quality and tuber yield of the early-maturing potato cultivar ‘Colomba’ under field conditions of the Pavlodar region of Kazakhstan. The aqueous extract was prepared from dried aerial parts of A. absinthium, while FeNPs were synthesized using the plant extract and FeCl₃ as a precursor. Scanning electron microscopy confirmed the formation of nanoscale particles with irregular, predominantly rounded morphology and pronounced agglomeration; representative individual particle measurements were 35.99, 45.86, and 61.08 nm. Both formulations were applied by foliar spraying according to three schemes: once before flowering, once during flowering, or twice at both stages. Potato yield was evaluated separately in the 2024 and 2025 growing seasons. Two-way ANOVA showed significant effects of treatment on total tuber number (F(6,126) = 4.603, p < 0.001) and total tuber weight (F(6,126) = 7.382, p < 0.001), as well as significant effects of year on both parameters. No significant treatment × year interaction was detected. Planned comparisons with Holm adjustment showed that double application of the aqueous extract and double application of the FeNP-containing formulation significantly increased total tuber number compared with the control. Double-application of both formulations also significantly increased total tuber weight, while significant increases in tuber weight were additionally observed for single pre-flowering applications of both formulations and for the FeNP-containing formulation applied during flowering. In the 2025 crop, starch content ranged from 5.48 to 10.14%, vitamin C from 18 to 30 mg/100 g, nitrate content from 40.6 to 69.2 mg/kg, and dry matter from 14.65 to 19.60%; these biochemical differences were interpreted descriptively because statistical significance was not established for these parameters. No treatment-related deterioration in the assessed browning characteristics of raw or cooked tubers was observed. The results indicate that double foliar application of the A. absinthium aqueous extract or the FeNP-containing formulation was the most consistently effective application scheme for improving ‘Colomba’ potato yield under the conditions of this two-year field experiment.