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Biotesting of nanomaterials assumes greater significance and includes various biological models. The research objective is to study the influence of different concentrations of nanoparticles (NP) of Zinc (Zn) on propagation, survival and activity of antioxidatic enzymes of metal in Eisenia fetida in artificial soil (AS) and microcrystalline cellulose (MCC). Zn nanoparticles in size of 90.7±0.3 nМ, Z-potential 25±0,5мV have been used for the analysis. Artificial soil and microcrystalline cellulose were used as substrates for the study. Zn nanoparticles in high concentrations (from 500 to 1000 mg/kg) cause immobilization of 60% of earthworms within 24 hours. The highest accumulation of metal in earthworms and high mortality were registered at a concentration of 500 mg/kg in microcrystalline cellulose and at 1000 mg/kg in artificial soil.It was established that after the increase in concentration from 50 to 500 mg/kg the activity of GPx and SOD in two substrates increases. The highest activity occurs when Zn nanoparticles have concentration of 500 mg/kg. The activity of catalase in worms reduced at the exposition in MCC, but it increased after increasing dosage of Zn NPs in the artificial soil.The study demonstrates that Zn nanoparticles in dose of 500 mg/kg induced the highest toxical effect. It was proven by behavioral reactions, growth characteristics and indices of enzymatic activity in organism of redworm. Based on the obtained data, substrate from microcrystalline cellulose can be used as experimental.

The paper presents a study of the main factors affecting the yield level of soft spring wheat. This research is based on the study of the biological activity of the soil and the content of nitrates in the Urals southern chernozems. This paper is obtained as a result of field and laboratory studies. The purpose of the research work is to establish the influence of each factor individually on the yield of grain crops according to various predecessors and backgrounds of mineral nutrition. For the first time in the experiment, the methodology of the field experiment, decomposition of linen (applications) and the ionometric method are used. Over 18 years, rich experience has been accumulated, and soil fertilizer options have been developed to increase wheat productivity. Studies show that using balanced fertilizer it is possible to increase the yield of wheat after growing millet in this territory to 9.7 centners per 1 ha, the dependence on the influence of the activity of microorganisms is 71.51 %. In other research options, after the application of mineral fertilizers during the growing season, grain yield of 9.4 and 9.0 kg per 1 ha is noted, and the proportion of the effect of nitrate-nitrogen is 33.82 and 24.67 %. The results obtained are of scientific and practical importance in the field of microbiology, chemistry, agriculture, agronomy and agricultural production.

Protected areas located in the steppe zone of Russia represent unique territories. Fires are a constant strong factor affecting the plant and soil components of ecosystems. The resistance of soils to fire in the conditions of semi-arid climate and hilly topography determines the speed of recovery of vegetation and soils in the steppe landscape. The study was devoted to the restoration of water-physical, physico-chemical and chemical properties of soils after the fire in 2014 on the site of the site «Burtinskaya Steppe» of the Orenburg State Nature Reserve (Russia). The study sites were represented by two polygons with burned and unburned (control) areas. The destruction of vegetation by fire contributed to the reduction of moisture reserves in the layer of 0-30 cm by more than 30% in the first years after the fire. For burning soils, there was a greater warming and migration of easily soluble salts and gypsum to the upper part of the soil profile. The most intense accumulation of СаЅО 4 and sodium salts was noted in the soils of polygon 1. The study of the fire influence on the content of soil organic matter and nutrients demonstrated their significant reduction in the first two years of research. The restoration of phosphorus and potassium content to the level of control sites was noted by the end of three years of monitoring. The content of soil organic matter and nitrogen significantly exceeded the values in control sites. The conducted research has allowed drawing a conclusion about the ability of soils of steppe landscapes to restoration of stocks of biogenic elements after the fire. At the same time, changing the granulometric composition and migration of soil salts up the profile can contribute to the restructuring of plant communities and change the basic properties of the soil cover. The particular danger of changing the soils of steppe landscapes arises in the context of recurring fires and changing climate. The observed post-pyrogenic dynamics of soil processes indicate the need for a deep and comprehensive study of the impact of fires on the soil as a key link in the functioning of steppe ecosystems.

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Investigation of SiO nanoparticles (NPs) effect on Eisenia fetida showed no toxic effect of the metal at a concentration of 250, 500 and 1000 mg per kg of soil, but conversely, a biomass increase from 23.5 to 29.5% (at the protein level decrease from 60 to 80%). The reaction of the earthworm organism fermentative system was expressed in the decrease in the level of superoxide dismutase (SOD) on the 14th day and in the increase in its activity to 27% on the 28th day. The catalase level (CAT) showed low activity at average element concentrations and increase by 39.4% at a dose of 1000 mg/kg. Depression of malonic dialdehyde (MDA) was established at average concentrations of 11.2% and level increase up to 9.1% at a dose of 1000 mg/kg with the prolongation of the effect up to 87.5% after 28-day exposure. The change in the microbiocenosis of the earthworm intestine was manifested by a decrease in the number of ammonifiers (by 42.01-78.9%), as well as in the number of amylolytic microorganisms (by 31.7-65.8%). When the dose of SiO NPs increased from 100 to 1000 mg/kg, the number of Azotobacter increased (by 8.2-22.2%), while the number of cellulose-destroying microorganisms decreased to 71.4% at a maximum dose of 1000 mg/kg. The effect of SiO NPs on Triticum aestivum L. was noted in the form of a slight suppression of seed germination (no more than 25%), an increase in the length of roots and aerial organs which generally resulted in an increase in plant biomass. Assessing the soil microorganisms' complex during introduction of metal into the germination medium of Triticum aestivum L., there was noted a decrease in the ammonifiers number (by 4.7-67.6%) with a maximum value at a dose of 1000 mg/kg. The number of microorganisms using mineral nitrogen decreased by 29.5-69.5% with a simultaneous increase in the number at a dose of 50 mg/kg (+ 20%). Depending on NP dose, there was an inhibition of the microscopic fungi development by 18.1-72.7% and an increase in the number of cellulose-destroying microorganisms. For all variants of the experiment, the activity of soil enzymes of the hydrolase and oxidoreductase classes was decreased.

The present study assessed the toxic effects and prospects of using nanoparticles of SiO2 and Fe3O4 by studying the influence of pre-sowing priming of Pisum sativum L. seeds with a suspension of nanoparticles of SiO2 and Fe3O4 in a concentration range of 10−2 to 10−5 mg/l. The results demonstrated the stimulating effect of the SiO2 suspension (10−3 mg/l and 10−4 mg/l) and the mix of Fe3O4+SiO2 at the corresponding concentrations of 10−3 mg/l and 10−4 mg/l on the length of roots and seedlings, and the increase in the viability of plant cells under the influence of a stress factor (based on Evans blue staining). Field experience has shown the ambiguous effect of nano-printing of seeds on plant productivity.

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