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Application of Microbiological Preparations in the Cultivation of Agricultural Crops with the Aim to Reduce the Technogenic Load of Metallurgical Plants

One of the ways to solve the problem of technogenic pollution is to implement biotechnologies for agricultural lands. The study aims to assess the efficiency of microbiological preparations in the cultivation of potatoes near metallurgical plants in the south of Eastern Siberia. The research was conducted in 2015-2016 on three plots located near Shelekhov aluminum production plant. The Japanese preparation EM and the Russian microbial preparations Baikal EM1 and Fitosporin-M were used. The effect of biological products on plant protection from fungal diseases was observed only in 2015. The two-year application of Fitosporin-M increased the potato yield (by 13-22%) on cultivated alkaline soils; on weakly acidic soils, an increase in the yield (by 26%) was observed only in 2016. When applying EM preparations, a stable increase in the yield (14-22%) was observed on weakly acidic soils; on alkaline soils, an increase in the yield was observed in less than 50% of cases. In general, the stable yield enhancement was observed when applying Fitosporin-M on the alkaline soils. The effectiveness of the EM preparations depended on the agrophone and weather conditions.


Introduction
Modern urbanization causes a high concentration of settlements near industrial cities. In these settlements, people grow various agricultural products. One of the most important tasks is to develop recommendations for using biologically safe technologies that can affect the application of chemical plant protection products [1]. Preparations based on symbiotic microorganisms have been developed to maintain the natural soil fertility, reduce the anthropogenic load on the environment and improve the quality of agricultural products. Microorganisms play an important role in the adaptation of plants to external factors, including the technogenic ones. Many symbiotrophic microorganisms are highly resistant to toxic substances, participate in their transformation in the rhizosphere and in the accumulation by plants, have a positive effect on the plant growth on technogenically contaminated soils, reduce the mobility of heavy metals, thereby protecting plants from toxicants under stressful conditions of technogenic pollution [2,3].
Currently, the most famous biological product is effective microorganisms (EM) composed of beneficial microorganisms. They do not contain synthesized or genetically modified cultures. These preparations began to be used in Japan more than 30 years ago. Now they are widely used in many countries with the aim to produce safe agricultural products [4-8] and solve biotechnology problems In Russia, the most famous microbiological preparation is Baikal EM1. It was developed by Irkutsk and Ulan-Ude researchers on the basis of Lake Baikal microorganisms. The main reason for the exceptional versatility of this drug is a wide range of actions of its microorganisms.
Baikal EM1 is based on more than 80 types of microorganisms. These microorganisms belong to ten orders which represent five families. EM cultures do not contain genetically modified strains. They are produced by mixing various groups of natural beneficial, non-pathogenic, aerobic and facultative anaerobic microorganisms [19].
In the Siberian region, the implementation of biotechnology is hindered by harsh natural and climatic conditions. However, they are used by farmers. Application of biological products in small areas does not yield the result promised by manufacturers, which has a negative effect on the mass implementation of biotechnology.
At the same time, an analysis of scarce data showed that in Siberia Baikal EM-1 and other microbiological preparations can be effective. The preparation has a protective and stimulating effect, improves the productivity and quality of agricultural products [20,21].
Thus, it is necessary to study applications of these biological products in Eastern Siberia in the crop cultivation under the high anthropogenic load. The most widely and universally cultivated crop in the region is potatoes.
The aim of the present study is to assess the effectiveness of microbiological preparations in the potato cultivation near metallurgical plants of the Southern Baikal region.

Materials and methods
The study was conducted in the suburban area of Shelekhov, one of the largest industrial centers in the south of Eastern Siberia. The industrial profile of the town is determined by non-ferrous metallurgy. Air pollution caused by emissions of the aluminum production plant causes a high level of soil pollution in the town and surrounding areas. 0.5-8 km away from this zone, an extremely and highly dangerous hygienic contamination of agricultural soils with water-soluble fluorine (7 MPC) and B(a)P (5 MPC) was identified [22]. The category of hygienic soil contamination has not changed and remains extremely dangerous.
The studies on the effectiveness of various biological products for growing potatoes were carried out in 2015-2016 on three plots near Shelekhov. The plots were located in three different settlements, where people grow agricultural products in their gardens.
The first plot was located two kilometers west of Shelekhov, in the floodplain of the Irkut river, 1 km from the river. The groundwater level was at a depth of three meters. Meadow soils were dominant in the adjacent areas.
The soil of the first plot was cultivated, sandy loam, light; the content of organic matter was about 3%, the soil solution reaction was alkaline (pH = 8.4).
The second plot was located in the floodplain of the Olkha river, 2.5 km east of Shelekhov near the groundwater.
On the second plot, the soil was technogenic, created by filling bog soils with conditionally fertile overburden from the sand and gravel quarries with the addition of humus. The soil was low-cultivated, sandy loam, light with a low content of organic matter (1%) and a weakly acidic reaction of the soil solution (pH = 6.2).
The third plot was located 4.5 km south of Shelekhov, on the southern slope of a gentle hill one kilometer from the floodplain of the Olkha river. In the adjacent areas, low-fertile podzolic soils were widespread. The soil was well cultivated, with a high content of organic matter (11%) and an alkaline reaction of the soil solution (pH = 8.2). By its mechanical composition, it was heavy loam, which caused poor soil aeration. Small-plot experiments were conducted on each plot by the same scheme in three replications. The area of each plot was 3 m 2 . Adretta potato variety was used in the study. The potato was planted at the optimal time; the cultivation technique was generally accepted in the region.
Three plots were treated with a solution of one of the biological products and one plot was watered. Three biological products were selected: Baikal EM 1 and Fitosporin-M (Russia) and an EM preparation (Japan) provided by the aquatic toxicology laboratory of the Research Biology Institute (Irkutsk State University).
The main cultures of the Japanese EM preparation are lactic acid bacteria Lactobacillus plantarum, Lactobacillus casei, Streptococcus lactis; phototrophic bacteria Rhodopseudomonas palustris, Rhodobacter sphaeroides; yeast Saccharomyces cerevisiae, Candidautilis; fungi Streptomyces albus, Streptomyces griseus, Aspergillus oryzae, Mucorhiemalis. In total, the Japanese EM preparation contains about 80 different microbial cultures.
The Baikal EM1 preparation is based on the following groups of microorganisms: phototrophic bacteria Rhodopseudomcnas and Rhodobalter, lactic acid sticks Zacdobacillus and lactic acid cocci Zacdococcus, yeast Saccharomyces. To enhance the vital activity of the microorganisms, the nitrogenfixing free-living azotobacteria Azotobacter and the bacteria Pseudomonas were introduced.
The active substance of Fitosporin-M is living cells and spores of Bacillus subtilis. A composition based on chalk, fillers and powedered OD-humate was used as a carrier of the bacterial culture.
In 2015, the experiment scheme was as follows: plot 1 -watering at the rate of 10 liters per 3 m 2 (control). Plot 2 -treating with Japanese EM preparation (1: 1000) at the rate of 10 liters per 3 m 2 . Plot 3 -treating with Baikal EM-1 (1: 1000) at the rate of 10 liters per 3 m 2 . Plot 4 -treating with Fitosporin (1: 500) at the rate of 10 liters per 3 m 2 . Differences in the concentration of the solutions were due to the manufacturers' recommendations. Since in 2016 the Japanese EM preparation was not accessible for the population, Baikal EM-1 was used instead (1: 100, 10 l per 3 m 2 ).
Plants were treated with biological products in the evening hours three times during the growing season with an interval of two weeks: at the beginning of the budding phase (the first decade of July), during the mass flowering and tuber ripening.

Results and discussions
In 2015, the meteorological conditions were close to the average long-term values. Visual observations showed that plants treated with biological products were less affected by fungal diseases, their vegetative organs developed better than in those on the control plot, and their terrestrial biomass died later (Table 1). This pattern was observed on all the plots. The application of the EM biopreparations on plot 2 increased the potato yield by more than 20% (Table 2). A significant increase in the yield (70%) was observed when applying the Japanese biopreparation on plot 1. Fitosporin-M increased the yield on the alkaline soils of plots 1 and 3 (by 18-20%). 1,07 ± 0,11 0,49 ± 0,05 0,80 ± 0,08 Application of Fitosporin-M 1,29 ± 0,08 0,40 ± 0,05 0,95 ± 0,06 In 2016, the moisture values differed from the average long-term ones. In the first ten days of August, atmospheric precipitation exceeded the average long-term level. At the beginning of the second decade of August, the floodplain of the Olkha River was partially flooded. Plot 2 was in the flooded zone, which killed the terrestrial biomass of plants; potato tubers were harvested three weeks earlier than usual. The effect of plant protection from fungal diseases was not observed.
A significant increase in the yield with Fitosporin-M was observed on all the plots (13-26%). The application of Baikal EM-1 provided an increase in the yield on plot 2 (by 14-20%) at different concentrations of the solution and on plot 1 (by 23%) at 1: 1000. It was not possible to establish any regularities caused by various concentrations. The inefficiency of Baikal EM1 on plot 3 was due to unfavorable aeration conditions that developed on the heavy loamy soils in 2016 due to the waterlogging.
According to [23], the most favorable conditions for microorganisms can be found on slightly acidic soils at pH = 6.5, where the number of bacteria is high. EM preparations contain microbiological cultures adapted to lower reactions of the environment [24]. Therefore, a stable effect from the EM preparations was observed only on low fertile, weakly acidic soils of plot 2. Unfavorable conditions may develop on alkaline soils. As a result, the EM preparations do not always realize their potential.

Conclusion
The 2015-2016 research results showed that in the suburban area of the Southern Baikal region, near the large metallurgical plant, the effectiveness of biological products in the potato cultivation was determined by the hydrothermal conditions of the growing season and agricultural background.
A more stable yield gain was observed when using Fitosporin-M. The effect of EM preparations was stable only on technogenic soils with a weakly acidic reaction of the soil solution. On alkaline soils with a high content of organic matter, an increase in the potato yield was in less than 50% of cases. It was not possible to identify any regularities.
On alkaline soils, which are common near aluminum production plants, it is most appropriate to apply Fitosporin-M, whose effectiveness depends on the agrophone, aeration and moisture.
EM preparations can be applied along with measures aimed to restore technogenically disturbed light soils with neutral and acidics reactions of the soil solution.