PHOTOSYNTHETIC ACTIVITY OF FODDER BEET PLANTS DEPENDING ON THE INFLUENCE OF MINERAL FERTILIZERS

Abstract

The article presents the results of studies on the influence of mineral fertilizer rates on the variability of leaf area and photosynthetic indicators of fodder beet plants in the conditions of the western Forest-Steppe of Ukraine. It was established that the use of mineral fertilizers significantly increases the photosynthetic activity of fodder beet crops. Thus, for the first decade of June, the average leaf area of the Sonet variety was 10.94 thousand m2/ha, for the Olzhych variety – 13.88 thousand m2/ha, and for the Starmon variety – 15.69 thousand m2/ha. The highest leaf area was noted for the first decade of August. The options where mineral fertilizers were used were better compared to the options without fertilizers. In terms of varieties, the largest leaf area of fodder beet was in the Starmon variety compared to the Sonet and Olzhych varieties. The highest value of the analyzed indicator was observed in the variant with the application rate N150P75K225 63.81thousand m2/ha, which is 28.1% more than the control. As of the harvest period, a decrease in leaf area was observed in fodder beet plants. During the years of research, the highest photosynthetic potential was during the period of intensive growth (10.08). Against the background of no fertilizers, the level of this indicator was within 2.275 million m2 × day/ha in the Sonet variety, 2.724 million m2 × day/ha in the Olzhych variety, and 3.279 million m2 × day/ha in the Starmon variety. The best conditions for increasing the photosynthetic potential were created when applying complete mineral fertilizer to the soil. The highest photosynthetic potential was in the Starmon variety against the background of fertilizers with the norm N150P75K225 and N225P75K150 – 4,764 and 4,589million m2 × days/ha. During the harvesting period, the photosynthetic potential of the studied varieties decreased almost to the same level as in July, however, during the years of research, the Starmon and Olzhych varieties still had a powerful assimilation apparatus at the time of harvesting, with the FP averaging 3.80 and 3.49 million m2 × days/ha versus 2.70 in the Sonet variety. The highest value of photosynthesis productivity was noted in the first decade of July (closing of rows). Thus, in the control plot, the productivity level was 4.23 g/m² per day for the Sonet variety, 4.26 g/m² per day for the Olzhych variety, and 6.43 g/m² per day for the Starmon variety. While, when fertilizers were applied, this indicator was within the range of 6.02-6.91 g/m² per day for the first variety, 6.98-7.84 g/m² per day for the second variety, and 10.06-11.23 g/m² per day for the third variety.