NECTAR-PRODUCING PLANTS AND CROP ROTATION: IMPACTS ON POLLINATORS AND YIELD IN HADYACH UTC, UKRAINE

Abstract

This study examined the composition, phenology, and ecological significance of nectar-producing flora in the agricultural landscapes of the Hadyach Urban Territorial Community (UTC), Poltava region, Ukraine. A total of 78 species, including native trees, ruderal herbs, meadow forbs, and cultivated crops, provided continuous nectar and pollen availability for honey bees (Apis mellifera) and wild pollinators from early spring to late autumn. Key species such as Tilia cordata, Robinia pseudoacacia, Helianthus annuus, and Phacelia tanacetifolia were identified as major contributors across different seasons. Field experiments demonstrated that the choice of preceding crop strongly influenced flowering phenology, floral density, nectar sugar content, pollinator visitation, and seed yield of Fagopyrum esculentum and H. annuus. Leguminous and nectariferous predecessors, including Melilotus alba, Phacelia tanacetifolia, and Glycine max, enhanced flowering duration, increased flower density by 5–49%, raised nectar sugar concentration by 41–136%, and improved seed yield by 17–46%. Current crop rotations, dominated by non-nectar-producing species, occupy only 18–20% of arable land, limiting temporal continuity of nectar supply. Expanding the share of nectariferous crops to 40–60% of cultivated area is recommended to stabilize nectar flows, support pollinator health, and enhance agroecological sustainability. Strategic integration of high-value nectar plants and perennial legumes into crop rotations can fill seasonal flowering gaps, improve soil fertility, and strengthen the resilience of agroecosystems.