The effect of bacterial preparations on the growth, development and quality indicators of sugar beet yield

Experimental samples of biological products based on endophytic microorganism strains were tested on sugar beet root plants. The studies were carried out at ZAI Agrofirm LLC, Zay District, the Republic of Tatarstan. The most effective preparations applied at the early stages (3–4 leaf phase) were RECB – 31 B (1.5 l/ha), RECB – 74 B (1.5 l/ha), RECB – 74 B (1.5 l/ha), RECB – 44 B (2.0 l/ha), RECB – 50 B (2.0 l/ha), and RECB – 74 B (2.0 l/ha). Biological preparations applied in the row closing leaf phase have an advantage over chemical preparations when applying RECB – 14 B (1.5 l/ha), RECB – 31 B (1.5 l/ha), RECB – 74 B (1.5 l/ha), RECB – 74 B (2.0 l/ha). At the late vegetation stages, experimental preparations increased the yield. A significant increase was observed when applying RECB – 95 B


Introduction
The intensive development of agricultural production, including plant protection products, contributed to a significant increase in sugar beet yields.
A promising direction in the ecologization of agriculture and agricultural technologies is the use of biological products. They can have immunostimulating and growth-regulating effects on plants [1][2][3].
In addition, chemical plant protection products do not always inhibit the spread of pathogens in agricultural crops, and biological products can be more effective against phytopathogens [4,5].
The use of biological products on sugar beets, one of the economically significant crops of the Chernozem Region, will reduce the use of chemical plant protection products and implement the genetic potential of hybrids plants [2]. The aim of the study is to test prototypes of biological products based on endophytic microorganism strains to increase the crop yield and the sugar content.
These strains can reduce the growth of seed and soil infection, as well as to increase the resistance of agricultural plants to adverse environmental conditions. Bacillus sp. Strains produce substances acting against pathogens, Pseudomonas putida can secrete growth stimulants, contributing to the plant growth, and Trichoderma viride can be used to produce antibiotics, stimulate growth and weight of the root system which increases the crop yield [6][7][8][9][10].
Field experiments were carried out in 2018 in the conditions of the ZAY agricultural company in Zay district, Zakamye (the Republic of Tatarstan).
Meteorological conditions in 2018 reflected the climate features of the forest-steppe zone of the Republic of Tatarstan with its unstable moisture during the growing season and a sharp fluctuation in air temperature.
The average daily temperature varied from +13.3in May to + 21.7in July, the amount of precipitation was 221.8 mm.
Land was treated to a depth of 30 cm by the Horsch aggregate. Pelleted seeds of sugar beet obtained from the Bravissima KBC hybrid were sown by the 18-row Monopill seeder. The main N96P72K macro-fertilizers were applied. Plants were sprayed with herbicides.
The allocation of plots was consistent, the experiments repeated thrice. Spraying with biological products was carried out once in different phases of sugar beet development (3-4 leaves, closing leaves in rows, closing leaves in inter-rows). Preparations were applied in different dosages: 1.5; 2.0 l/ha. The generally accepted methods and relevant GOSTs were used during the experiments. Sugar content was determined using a SU-4 polarimeter-saccharimeter in the laboratory of Zay Sugar LLC. The results were processed by the methods of variance and correlation-regression analyzes [11].

Results
The results of the experimental studies are presented in Table 1. The yield of sugar beet root crops changed as follows: when spraying in the 3-4 leaf phase, the largest reliable increase was obtained in the options: The treatment of plants with biological preparations in later phases (closing leaves in inter-rows) revealed the effect of RECB -95 B (1.5 l/ha) with increased the yield by 9.68 t/ha.
In the agricultural production of sugar beets, the yield and sugar content are crucial.
The results of identification of sugar content are presented in Table 2. During the period of early treatment with biological products (3-4 leaf phase), when applying RECB -50 B (1.5 l/ha) and RECB -74 B (1.5 l/ha), the highest sugar content was observed: an increase was 0.94 and 1.7, respectively.
In the phase of inter-row closing leaves, RECB -50 B (2.0 l/ha) showed an increase in the sugar content by 1.01 %.
A significant increase in the yield influenced the sugar content; this indicator had the same dynamics. The total yield of sugar varied from 3.73 to 12.59 t/ha.
Thus, biological products have the greatest biological effectiveness with a single treatment in the phase of 3-4 leaves with an increase in the yield from 7.29 to 31.72 t/ha. The highest sugar yield was observed when applying RECB -44 B (2.0 l/ha) -12.6 t/ha.

Conclusion
The research results showed that the biological products are promising and can be recommended for applying in different phenological phases.