Photosynthetic activity of crops and sequestration of atmospheric carbon by meadow clover and spring wheat in crop rotation

The purpose of the research is to estimate the intensity of absorption of light energy by crop rotation crops during the growing season and determine the amount of atmospheric carbon absorbed during photosynthesis. In a long-term stationary experiment, the absorption of photosynthetically active radiation (FAR) by crops of meadow clover for 2 years of use and spring wheat in variants without fertilizers and when applying N₆₀P₆₀K₆₀ was studied. Chlorophyll A, chlorophyll B and carotene, which serve as photoreceptors-pigments of photosynthesis in higher plants, were used to assess the intensity of absorption of light energy. The most active period of absorption of HEADLIGHTS by meadow clover leaves was noted from the stalking phase to flowering, the amount of chlorophyll A and B in the leaves was 11.08…14.32 mg/g dry weight, carotene – 2.2…3.3 mg/g dry weight. During photosynthesis, the carbon content in clover leaves varied in the range of 40.4…45.5 %. The content of the main products of photosynthesis, sugars, decreased from 9.8 % in the stalking phase to 3.4 % during seed formation. The most intensive process of photosynthesis of spring wheat took place during the period from the tillering phase to the beginning of maturation, the chlorophyll content was 9.14…11.90 mg/g dry weight, carotene was 2.5…4.3 times lower. Most sugars were noted at the beginning of entering the tube: without fertilizers – 15.3 %, when applying NPK of 60 kg d. v./ ha – 17.2 %. The amount of carbon absorbed by meadow clover crops during photosynthesis during the growing season, depending on the experimental options, was 2.26…2.42 t/ha (8.09…8.66 t/ha CO₂), spring wheat – 1.49…1.93 t/ha (5.33…6.90 t/ha CO₂).