THE FORMATION OF MAIZE CROPS PRODUCTIVITY DEPENDING ON NITROGEN-FIXING BACTERIA PRODUCTS, MYCORRHIZA AND NITROGEN NUTRITION LEVEL IN THE STEPPE ZONE OF THE ALTAI PRIOBYE (THE OB RIVER AREA OF THE ALTAI REGION)
The research goal was to evaluate the effect of the combined application of mineral fertilizers and biological products based on the rhizosphere nitrogen-fixing bacteria and mycorrhiza on maize productivity and nutritional value. The studies were conducted in 2013-2014 on the experimental field of the Altai State Agricultural University on chernozem medium humus soil. The research years differed significantly in terms of moisture water and heat availability; the growing period of 2014 was more favorable. The experiment included non-fertilized background and two fertilizer backgrounds - R <sub>60</sub>K <sub>60</sub> and N <sub>30</sub>R <sub>60</sub>K <sub>60</sub>. The effect of mono-products Rizoagrin, Bioplant-K and Mikoriza and binary mixtures of Rizoagrin and Bioplant with mycorrhiza was studied against those backgrounds. The variant with N <sub>60</sub>P <sub>60</sub>K <sub>60</sub> was studied separately. It has been found that maize cultivation for silage in the steppe area of the Altai Region is most promising when applying microbial products based on associative nitrogen-fixing bacteria (Bioplant-K, Rizoagrin) and mycorrhiza. The application of binary mixtures of nitrogen-fixing bacteria and mycorrhiza is particularly effective. The efficiency of the products increases when used combined with mineral fertilizers. The mineral fertilizer N <sub>30</sub>P <sub>60</sub>K <sub>60</sub> background was the most optimal from the studied backgrounds; it ensured productive functioning of nitrogen fixation system. The maize herbage yield against that background exceeded the control by 40.4-92.4%, while the herbage yield against non-fertilized background exceeded by 7.9-27.0% only and it was higher than the yield in the variant with N <sub>60</sub>P <sub>60</sub>K <sub>60</sub>. The maximum maize yield in both years of the research was obtained when the seeds were inoculated with a binary mixture of Bioplant + Mikoriza against the background of N <sub>30</sub>P <sub>60</sub>K <sub>60</sub>. The two-year average dry matter yield in that variant made 5.95 t ha exceeding the control by 138%. The application of that mixture of products maximized the protein content and its recovery with the harvest, and reduced the fiber content and improved forage digestibility.