Optimisation of plant nutrition under the influence of biopreparations in integrated sunflower cultivation technologies

The increasing production of sunflowers is driven by multiple factors, including the introduction of high-intensity hybrids, an advanced fertilisation system, a balanced plant protection strategy, and modern high-efficiency machinery. Further technological improvements require identifying new approaches based on factor interactions or their combined application. One such approach involves the use of biopreparations, which not only enhance productivity but also reduce pesticide load, a crucial consideration in the current ecological context. This study aimed to determine the impact of mineral fertilisers and foliar application of a biopreparation on sunflower seed productivity. The effects of mineral fertilisers and biopreparations on seed productivity formation were examined. The influence of biopreparations on sunflower growth, development, and productivity under varying mineral nutrition conditions was established. It was found that the application of biopreparations during pre-sowing cultivation positively affected crop yield, both in the absence and presence of mineral fertilisers. The use of biopreparations contributed to increased sunflower yield, with one of the tested biopreparations leading to a 6.9% increase, while the combined application of two biopreparations resulted in a 10.7% increase compared to the unfertilised control. Under mineral nutrition conditions (N60P60K60), the yield increase resulting from biopreparation application ranged from 0.21 to 0.17 t/ha, depending on the fertiliser dosage. The study also revealed positive changes in the microbiological state of the soil under the influence of biopreparations. The reduction in pathogenic fungi during the ripening phase reached 10.1% when a biopreparation was applied in the absence of fertilisers. The use of biopreparations also reduced the intensity of mineralisation processes, facilitating more efficient nitrogen uptake by plants. The dynamics of alkaline-hydrolysable nitrogen, available phosphorus, and potassium content confirmed the beneficial effects of biopreparations on the soil biogenic regime and plant nutrition. The findings support the feasibility of incorporating biopreparations into sunflower cultivation technologies, contributing to increased crop yields and improved soil ecological conditions. The results can be utilised to maximise the genetic potential of sunflower plants and ensure stable productivity