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Research was carried out in order to study the effect of new biologics based on rhizosphere microorganisms on yield and the spring wheat grain's quality. The work was carried out in 2018–2020 in the Ulyanovsk oblast on leached heavy loam chernozem in a microfield experiment in vessels without a bottom with an area of 0.018 m2. The experiment's scheme was as follows: Р45K4 (control)—background 1; background 1 + Strain KL‑10; background 1 + Strain 17–1; background 1 + Rhyzoagrin; N45Р45K45—background 2; background 2 + Strain KL‑10; background 2 + Strain 17–1; background 2 + Rhyzoagrin; N45Р45K45. It was discovered that presowing inoculation of spring wheat seeds with new biological preparations based on associative rhizobacteria's strains increases grain weight by 19–22%. The increases from the Rhyzoagrin biologics' use on Р45K45 as a standard averaged 66 g/m2 (+13% to Background 1), 98 g/m2 (+19%) from strain KL‑10, and 113 g/m2 (+22%) from strain 17–1. On the NPK background, the biologic based on 17–1 was most effective: 80 g/m2 (+15%). The maximum yield obtained from N90 was 789 g/m2 (+51%), 647 g/m2 (+24%) from N45, which is comparable to 17–1 (636 g/m2). The raw protein's collection increase from the introduction of N90 to 80% as a result of exposure to nitrogen nutrition, crop production, from the biological products' usage, or N45 was by 25–32%. The nitrogen fertilizers' and biologics use positively affected the accumulation of nitrogen consumed in the grain, increasing the nitrogen index (the share of nitrogen accumulated in the grain from its total accumulation in the crop) from 64 to 71%, increasing the ammonium nitrate nitrogen's payback with the grain harvest's growth by 52 –67%. [ABSTRACT FROM AUTHOR]

In dark gray forest soil, the use of 15N fertilizer nitrogen by spring wheat when seeds were inoculated with microbial biopreparations was assessed. The use of the method under study increased the weight of grain on the PK background by 25–42%. Increases from inoculation with preparations based on diazotrophs Ch-13 and V 167 strains were equivalent and amounted to 78–97 g/m2. In the variant with V 417, the increase reached 132 g/m2 and was at the level of use of N45 (143 g/m2). In combination with N45, the biopreparation based on strain Ch-13 was characterized by maximum efficiency. When using biopreparations on the PK-background, the accumulation of N in the yield increased by 2.33–2.64 g/m2 and by 1.33–1.70 g/m2 on the NRK background. In the variants with biopreparations, the 20% of the yield was formed due to biological nitrogen, while its greatest accumulation (24.8%) occurred when using V 417. The maximum share of 15N (23.7%) in the yield was noted when N90 was applied. When using biopreparations, plants accumulate approximately 8.5% of "extra"-N and its highest content (11.5–12.1%) was recorded when Naa was added. Mineral fertilizer nitrogen mainly accumulates in grain (95–96%) and only 4–5% accumulate in spring wheat straw. When applying N45 and N90, plants use 46 and 42% of fertilizer nitrogen, respectively, and the use of biopreparations increases the value of this indicator to 51–53%. Approximately 33–36% of the introduced dose of 15N is fixed in the soil, and this indicator increased up to 30% when using biopreparations. Losses of 15N reach 33–36%, while losses decrease to 17–19% with the introduction of biopreparations. The minimum accumulation of fertilizer nitrogen in plants (42%), the maximum fixation in the soil (36%), and losses (23%) were observed when N90 was applied. [ABSTRACT FROM AUTHOR]

The results of research on the influence of biologics based on rhizosphere microorganisms on the yield of spring wheat grain on different backgrounds of mineral nutrition on sod-podzolic light-loamy soil are presented. It was found that inoculation of spring wheat seeds with biologics provides an increase in grain yield by 1.2–1.3 times, while nitrogen fertilizer at doses of N45 and N90 provide increases by two and 3.5 times, respectively. The collection of raw protein due to the improvement of nitrogen nutrition increases with the introduction of N45 by two times and with N90 by 3.6 times; that with the use of biological products is by 25–45%. The vast majority of the nitrogen consumed accumulated in the grain, while less in the straw. The grain of spring wheat, while improving the supply of nitrogen to plants during the growing season, contained 76–81% of thiselement from the accumulated harvest. It is concluded that the use of biologics on sod-podzolic light-loamy soil has a positive effect on the growth of spring wheat grain mass, improves the quality of products, and increases the payback of mineral fertilizers by increasing the yield. [ABSTRACT FROM AUTHOR]

The use of soil nitrogen by spring wheat plants in sod-podzolic medium loamy soil enriched with a stable nitrogen isotope 15N was researched in a model experiment involving the application of ammonium nitrate and white mustard biomass and seed inoculation with associative nitrogen fixer Rhizoagrin. It is established that plants primarily consume nitrogen contained in the recently applied mineral fertilizer. After the application of white mustard biomass and seed inoculation with Rhizoagrin, spring wheat consumes soil nitrogen; after the combined application of the above components and ammonium nitrate, spring wheat consumes both soil nitrogen and nitrogen contained in the fertilizer. The plant biomass accumulation increases predominantly due to nitrogen contained in the recently applied mineral fertilizer, regardless of whether it was applied separately or in combination with green manure and seed inoculation with the biopreparation. The increase in the plant biomass accumulation reaches 14–28% in comparison with the control variant (no fertilizers). After the application of the nitrogen fertilizer, either separately or in combination with green manure and the biopreparation, the concentration of nitrogen in spring wheat increases by up to 1.5 times. A clear upward trend is observed in relation to the nitrogen concentration in plants after the application of white mustard biomass and seed inoculation with Rhizoagrin. As a result, the total nitrogen accumulation in plants increases twofold after the application of the nitrogen fertilizer and by 1.2 times after the application of white mustard biomass and seed inoculation with the biopreparation. This is due to the presence of nitrogen compounds available to plants in the growing medium. The accumulation of 15N in plants characterizes the consumption of soil nitrogen by them. This parameter decreases after the application of the nitrogen fertilizer and remains equal to that in the control variant (no fertilizers) after the application of white mustard biomass and Rhizoagrin. This indicates that plants consume large amounts of mineralized soil nitrogen after the application of the two latter components and that nitrogen fertilizer is not a factor in the mineralization of soil organic matter. The application of white mustard biomass prior to spring wheat sowing and inoculation of its seeds with Rhizoagrin ensure that plants consume soil nitrogen in the initial vegetation period. [ABSTRACT FROM AUTHOR]

Biomass of spring wheat on sod-podzolic soil largely forms due to soil nitrogen, the share of which reaches four-fifths of the total removal of the element when using mineral fertilizers. Inoculation increases the fertilizer nitrogen use efficiency by 4.5% and reduces losses by 7%; there is a trend to increase the immobilization of N fertilizers. Stability of an agroecosystem is characterized by nitrogen flows. During the growing season of spring wheat, the amount of mineralized nitrogen depending on the fertilizer amounts to 17.4–18.0 g/m2, while the amount of reimmobilized nitrogen is 4.4–4.9 g/m2 and net-mineralization (N-M) is 13.1 g/m2. The inoculation of seeds with Rhizoagrin does not significantly affect the processes of mineralization (M) and reimmobilization (RI) in anything but a positive trend of increase in mineralization and reimmobilization of nitrogen in the soil. The use of nitrogen fertilizer brings the agroecosystem into a state of resistance (the maximum threshold limit of exposure (RI : M = 25% and N-M : RI = 3)). On average, over the years of research, inoculation of seeds with Rhizoagrin did not change the indicators of an agroecosystem's stability with the application of the fertilizers. [ABSTRACT FROM AUTHOR]

The use of white mustard biomass as green manure for spring wheat increased the grain yield by 58%, and the introduction of nitrogen fertilizer in the dose of N45 increased it by 42%. Inoculation of seeds with rhizoagrin (RA) ensured an increase in grain yield by 15%. The maximum grain yield was obtained by introducing mustard biomass and ammonium nitrate and inoculating the seeds with RA (+120%). At the same time, the content of raw protein in the grain increased to a greater extent with the addition of mustard biomass (+0.8%) and nitrogen fertilizer (+0.7%). When treating seeds with RA, the protein content of the grain tended to increase. Sustainability of the agroecosystem is characterized by nitrogen flows. During the growing season of spring wheat, the amount of mineralized nitrogen, depending on the fertilizer, reached 17.7-30.2 g/m, while the amount of reimmobilized nitrogen was 4.4-15.1 g/m2. Inoculation of seeds with RA did not significantly affect the processes of mineralization and reimmobilization; only a tendency of increase in mineralization and reimmobilization of nitrogen in the soil was noted. Indicators of the integral evaluation of functioning of the agroecosystem in the sowing of spring wheat with the introduction of mustard biomass indicate that the system is in a sustainable state (homeostasis) (RI: M = 50%, N-M: RI = 1.0). The use of nitrogenous fertilizer brings the agroecosystem to the resistant state: the zone of maximum permissible exposure level (RI: M = 25%, N-M: RI = 3.1). On average, over the years of research, inoculation of seeds with RA did not change the resistance indicators of the agroecosystem during fertilizer application. [ABSTRACT FROM AUTHOR]

The results of 26 field and microfield experiments using associative nitrogen-fixing bacteria biopreparations are generalized and analyzed. The efficiency of its use has been determined for spring wheat that is cultivated against different mineral nutrition backgrounds in the main soil types in the European part of Russia. It has been established that the inoculation of spring wheat seeds with the Rhizoagrin biopreparation combined with the PK fertilizer increases the grain yield by 23% on chernozem soils, by 14% on gray forest soils, and by 13-18% on sod-podzolic soils. The use of diazotroph biopreparation increases the coefficient of utilization of nitrogen from mineral fertilizers by 1.6 times on chernozem soils and by 1.2 times on sodpodzolic soils. In addition, the profitability of fertilizer nitrogen using seed inoculation increases by 2.2 and 1.1-1.4 times, respectively. Associative nitrogen fixation leads to the accumulation of 8-10 kg N/ha per year in sod-podzolic loamy soils and 12 kg N/ha per year in chernozem soils under spring wheat. [ABSTRACT FROM AUTHOR]