Photosynthetic activity of soybean varieties depending on the level of fertilization

Abstract

The conditions of activating the photosynthetic activity of soybean varieties of different ripening groups depending on organic and mineral fertilizers in the southern forest-steppe of the Central Chernozem region have been studied. It was found that, on average, over three years of research, crops of the medium-ripening variety Belgorod 48 under the combined application of straw-litter compost (20 t/ha), ammonium nitrate (30 kg/ha N) and Azosol 36 Extra (2 x 2 l/ha) formed the largest leaf surface area – 42.2 thousand m2 / ha, which was on 44% higher than in the control, and the maximum photosynthetic potential 1643 thousand m2·day/ha, which provided the 42% increase. Photosynthesis process in the crops of the early-ripening Lancet variety with the use Azosol was the most productive - on average, during the growing season, 7.1 g/m2·day. Correlation analysis between the studied photosynthetic activity indicators and soybean yield showed that when the fertilization level was saturated, the favorable conditions for the plant growth and development, the photosynthesis intensity and the outflow of synthesized substances into seeds were created. Varietal specificity wasmanifested in the fact that the medium-ripening variety Belgorodskaya 48 used the prolonged action of compost more effectively, while the early- ripening variety Lancet preferred fertilizers based on ammonium nitrate.