Keywords: Silphium perfoliatum L., nitrogen fertilizers, mowing time, development phases, net photosynthetic
productivity, photosynthetic potential, yield productivity

// Мелиорация.– 2021. – №2(96) – P 55–61

The article considers the photosynthetic activity of plants by the phases of development during the application of nitrogen fertilizers and during the aftereffect of mowing periods in the second year of plant life, as well as the effect of photosynthetic activity of plants on seed yield. The positive effect of increased doses of nitrogen fertilizers, as well as the earlier mowing periods on the photosynthetic activity of plants, is noted. A strong relationship between photosynthetic activity and seed yield during the application of nitrogen fertilizers has been established.