Peculiarities of photosynthesis in spelt (Tríticum spélta L.) in the Forest Steppe Zone of Ukraine
Authors: Karpuk L. M. , Zaika N. V. 
Published: October 2023

Purpose. To reveal the peculiarities of the influence of the cultivation technology elements on the course of photosynthetic processes in sowings.
Methods. The research was carried out in the years 2019–2022 at the experimental field of the Scientific Research Center of Bila Tserkva National Agrarian University (Kyiv region) located in the zone of unstable soil moisture of the Right Bank Forest Steppe of Ukraine. Spelt varieties ‘Zoria Ukrainy’, ‘Europe’, and ‘Atterhauer Dinkel’ were grown with the application of foliar fertilizer potassium humate HK-17 (400 g/ha) in the earing and milk ripeness stages, and Agriflex Amino growth regulator (200 g/ha) in the earing stage. 
Results. In the flowering stage, the average leaf area in the experiment was 44.9 thousand m2/ha. In particular, in variety ‘Zoria Ukrainy’ it was 45.3 thousand m2/ha, ‘Europe’ 45.5 thousand m2/ha, and ‘Atterhauer Dinkel’ 43.8 thousand m2/ha. A positive effect of foliar application of potassium humate in the earing stage was determined. Potassium humate contributed to an increase in the leaf area in the flowering stage of 2.1 thousand m2/ha, while an increase in the leaf area provided by application of Agriflex Amino in the earing stage was 1.0 thousand m2/ha. In the stage of milky grain ripeness, the average leaf area was 27.1 thousand m2/ha: 27.6 thousand m2/ha in ‘Zoria Ukrainy’, 27.8 thousand m2/ha in ‘Europe’, and 25.9 thousand m2/ha in ‘Atterhauer Dinkel’. The application of potassium humate HK-17 in the earing stage contributed to obtaining a additional leaf area of 0.98 thousand m2/ha and Agriflex Amino of 0.48 thousand m2/ha. At the same time, the application of potassium humate HK-17 in the stage of milk ripeness did not affect the change of this indicator. The highest indicators of net productivity of photosynthesis in variety ‘Zoria Ukrainy’ (1.07–1.08 g/m2 of dry matter per day) were in the treatment with potassium humate HK-17 in the earing stage and repeated in the milk ripeness stage. On the other hand, in ‘Europe' variety, the treatment with potassium humate in the earing stage repeated in the milk ripeness stage in combination with the application of Agriflex Amino growth regulator in the earing stage was 1.17 g/m2 of dry matter per day: it appeared the best treatment. The highest indicators of NPP were in sowings of ‘Atterhauer Dinkel’ variety, despite the fact that it had a slightly smaller leaf area. In particular, in the case of application of potassium humate in the earing stage repeated in the milk ripeness stage, the NPP was 1.18 g/m2 of dry matter per day, and for the combination with the application of Agriflex Amino growth stimulator in the earing stage it was 1.21 g/m2 of dry matter per day.
Conclusions. The conducted research confirms the expediency of the foliar application of fertilizer potassium humate HK-17 and growth regulator Agriflex Amino in cultivation of spelt, which improves the course of photosynthetic processes in sowings during vegetation and thus provides optimal conditions for the obtaining high crop productivity.