INFLUENCE OF MOLASSES BARD ON POTATO AGROCENOSIS PRODUCTIVITY AND BIOLOGICAL STATE OF SOD-PODZOLIC SOIL

Abstract

In the current context of agricultural transformation driven by climate change and rising costs of mineral fertilizers, the implementation of environmentally friendly and economically viable organic fertilizers is becoming increasingly important. One of the promising approaches is the use of by-products from the food and alcohol industries, such as molasses stillage – a liquid organic material rich in macro- and micronutrients, biologically active compounds, and organic matter that contributes to nutrient cycling in agroecosystems. This paper presents the findings of a three-year field study (2022–2024) focused on assessing the impact of molasses stillage as a fertilizer on the productivity of Bellarosa potato agrocenosis and the biological status of sod-podzolic soil in the Western Polissia region of Ukraine.Stillage was applied at three doses (10, 20, and 30 t/ha), with comparisons made to an unfertilized control and a conventional mineral fertilization scheme (N90P70K170). Throughout the study, biometric parameters were recorded, yield performance was assessed, and one of the key microbiological indicators – cellulolytic activity – was determined by monitoring the decomposition rate of flax fabric in soil horizons.It was established that the application of stillage at 20–30 t/ha significantly improved tuber biometric indicators (increases in mass by 21–34% and diameter by 17,2–27,6%), ensured a stable yield increase up to 25 t/ha (a 31,5% gain over the control), and notably enhanced soil microbial activity. At the highest dose (30 t/ha), flax decomposition intensity reached 93,75% in the upper soil layer and 79,15% in the lower one, indicating a high level of microbiological function. The reliability of the results was confirmed by strong correlations between fertilizer dose, yield, and microbial activity (r = 0,944–0,984).The practical value of the research lies in substantiating the use of molasses stillage as a local organic resource within organic farming systems, balancing agronomic efficiency with environmental safety. A 20 t/ha dose was identified as optimal, as it provides both productivity benefits and improved biological soil function without inducing secondary salinization. The findings can be integrated into sustainable soilfertility management strategies for regions characterized by sandy-textured and low-buffer capacity soils.