Photosynthesis process regulation i.e. its productivity increasing – is one of the most effective methods of influence on the sugar beet productivity, and for them - an important means of yield level increasing.

Researches have established that on the efficiency of sugar beet photosynthesis is significantly influence the timing of micronutrients foliar feeding, types and norms of their application. Observation of the growth and development of sugar beet plants assimilation surface on the date of registration when microelements is making in the closing leaves in a row phase was showed that leaf surface area depending on the term, types and norms of microelements application on average was ranged between 34.5 to 46.6 thousand m2/ha.

On the control variant (without feeding), average for research years, the leaf surface area was 34.5 thousand m2/ha and its higher value was obtained in the variant of Reakom-plus-beet application in the norm of 7 l/ha – 46.6 thousand m2/ha, that is caused by optimal area of ​​plant nutrition and the best leaf surface assimilation apparatus formation. The smallest value of the leaf surface index, relative to the control, was obtained in the areas with Reastim-humus-beet and Reakom-plus-beet micronutrients application in the norm of 3 l/ha, respectively, 37.5 and 35.5 thousand m2/ha. That is, on leaf surface increasing a significant influence had as a form of micronutrients and the norm of application. On a variant with using for foliar feeding Reastim-humus-beet at the application norms of microelements increasing from 3 to 7 l/ha the leaf surface area was increased on 7.0 thousand m2/ha, and on the plots with Reakom-plus-beet application the leaf area was increased on 11.1 thousand m2/ha.

According to the research results on the variants with the application of various types of micronutrients with different norms, on the first of September the photosynthetic potential was average and was within 1.03-1.40 million m2 × days/ha. So, on the variant with the application of Reakom R-beet (standard) micronutrient in the norm of 5 l/ha the index of photosynthetic potential was 1.15 million m2 × days/ha, which is on 0.12 million m2 × days/ha higher than on the control variant (without application).

High indicators of photosynthetic potential were obtained in variants with Reastim-humus-beet and Reakom-plus-beet microfertilizers application in the norms of 5 and 7 l/ha. In comparison with the application norm of 3 l/ha these indicators were increased on 0.06–0.34 million m2 days/ha.

Reakom R-beet, Reastim-humus-beet and Reakom-plus-beet microfertilizers foliar feeding application amid a general background of fertilizer is establishing appropriate conditions for the photosynthetic process intensity increasing, especially pure photosynthetic productivity. The most favorable were areas in which the feeding was carried out in closing leaves in a row phase with the norm of micronutrients application of 5 and 7 l/ha. At Reakom R-beet application in the recommended norm of 5 l/ha for the production the pure photosynthetic productivity was 5.67 g of dry matter/m2 leaf area per day, at Reastim-humus-beet application in the norms of 5 – 5.96 and 7 l/ha – 6.26 g dry matter/m2 leaf area per day respectively. After Reakom-plus-beet application in the norms of 5 and 7 l/ha, the pure photosynthetic productivity was respectively – 6.50 and 6.61 g dry matter/m2 leaf area per day. Given that in these variants there was a high photosynthetic potential (1.15–1.40 million m2 × days/ha) and has created a favorable physiological background for productive work of each plant cell by the expense of micronutrients application, it were created the necessary conditions for a high level of photosynthesis process passing.

At the second period of micronutrients application were also determined the indicators of photosynthesis productivity. It should be noted that the indicators of leaf surface area in all variants were almost in a par, as in the variants after the first term of micronutrients foliar feeding were in the range of 32.1 to 50.6 thousand m2/ha. Photosynthetic potential value (0.96–1.52 million m2 × days/ha) and pure photosynthetic productivity (4.65–6.31 g dry matter/m2 leaf area per day) were lower in comparison with the first period of micronutrient application.

Summing up it should be noted that foliar feeding application in closing leaves in a row phase is delivers the productivity of photosynthesis increasing, particularly in variants where used Reakom R-beet microfertilizer at application norm of 5 l/ha, Reastim-humus-beet at application norms of 5 and 7 l/ha and the Reakom-plus-beet at the same norms, which resulted the high indicators of leaf area from 38.4 to 46.6 thousand m2/ha , the photosynthetic potential of 1.15 to 1.40 million m2 × days/ha and pure photosynthetic productivity from 5.67 to 6.61 g dry matter/m 2 leaf area per day, and this in turn is impact on sugar beet final productivity. On pure photosynthetic indicators productivity it is possible to predict the sugar beet productivity depending on the norms and types micronutrient application in feeding.

Key words: sugar beet, microfertilizer, foliar feeding, photosynthetic productivity.