Physiological and biochemical aspects of pre-sowing treatment of soybean (Glycine max (L.) Merr.) seeds

Soybean is one of the most in-demand crops, with its production increasing; however, climate change affects yield, necessitating the application of biopreparations to enhance plant resilience to stress conditions. This study aimed to investigate the effects of pre-sowing seed treatment with an inoculant and a phytohormonal preparation on the physiological and biochemical parameters of soybean plants and their yield under organic farming conditions. A field study conducted in 2022-2024 examined the impact of pre-sowing seed treatment with the inoculant Legume Fix and the phytohormonal preparation Violar on leaf area, proline content, malondialdehyde levels, photosynthetic pigments, and yield under various weather conditions in an organic farming system. It was established that pre-sowing seed treatment increased leaf area by an average of 13.4% with Legume Fix and by 19.3% with Violar. It was established that the highest increase in proline content (as a protective response) was observed in the hot conditions of 2024, with seed treatment using Violar (41.2%) and Legume Fix (26.5%). Over the study period, the lowest MDA concentrations in soybean plants were recorded following seed treatment with Violar and Legume Fix, averaging 7.57 and 9.33 µg/g fresh weight, respectively, which was 37.4% and 22.9% lower than in the control plants. Treatment with Violar resulted in an increase in Chl a, Chl b, and total Chl (a+b) content by an average of 18.9%, 13.3%, and 17.2%, respectively, compared to the control, while inoculation with Legume Fix led to increases of 7.4%, 3.4%, and 6.2%, respectively. Pre-sowing seed treatment with Legume Fix and Violar resulted in a higher yield than the control plants, with average increases of 13.2% and 20.6%, respectively. The obtained results may be recommended for organic farming to enhance crop yield