Carbon dioxide is absorbed by plants during photosynthesis and the intensity of this process depends on the solar radiation coming to this territory, the temperature regime, the availability of moisture and batteries. The amount of CO2 absorbed by plants is determined by the accumulated dry biomass or yield. The potential yield of field crops in production conditions is not always achieved. The paper presents the results of studies on the effect of calculated doses of mineral fertilizers on various types of soils with different moisture indicators on the formation of dry biomass by spring durum wheat. Field experiments were carried out on gray forest soils in 2005-2008, which occupy 43.7% of agricultural land in the Republic of Tatarstan and chernozems in 2001-2003, occupying 39.9%. The assimilation of mineral nutrition elements from soil and fertilizers by plants is influenced not only by the type of soil, but also by the availability of productive moisture. In the studies of 1984-1987, the effect of fertilizers and irrigation on the intensity of accumulation of dry biomass by spring durum wheat was studied. The use of calculated doses of mineral fertilizers on leached chernozems on average for 1984-1987 increased the accumulation of dry biomass of spring durum wheat by 45.6%, and in combination with irrigation by another 57.4%. In the experiments of 2001-2003, calculated doses of mineral fertilizers increased the accumulation of dry biomass by 20.7% on the chernozems of the Transcamian region of the Republic of Tatarstan, and by 13.6% on the gray forest soils of the Pre-Kama region in 2005-2008

The article presents the results of research conducted in different soil and climatic conditions of the Middle Volga region on the influence of regulated factors, as well as environmental factors on the production process of plants of various types of spring wheat. The amount of photosynthetically active radiation (PAR) is enough to obtain yields within 12–13 tons of dry biomass or 6–7 tons of grain. Natural precipitation is able to provide 3.82–4.36 t of spring wheat grain from 1 ha, and 4.5–6.3 t/ha by the total influence of solar energy, heat and moisture supply. Natural level of soil fertility without application of organic and mineral fertilizers allows to receive about 2 tons of spring wheat grain from 1 ha. Application of nitrogen in the form of ammoniac water (N-20.5 %) increased the yield in comparison with the use of nitrogen in the form of ammoniac saltpeter: the increase was 0.14 t per 1 ha. In the conditions of grey forest soil in the Predkamye region of the Republic of Tatarstan the optimal norm of sowing of spring wheat Triticum dicoccum Schuebl (spelt) depending on the feeding background was established. Growth of yield at sowing of 6 million seeds per hectare at all levels of nutrition in comparison with sowing rate of 4 million tons per hectare was 0.18 tons per hectare against the natural background, against the estimated background of NRC on 2.0 tons of grain – 0.19 tons and 2.5 tons of grain – 0.24 tons per hectare. The maximum yield increase was received at a combination of a mineral foodstuff with an optimum norm of sowing and has made on a settlement background 2 tons of grain from hectare – 0.20 tons, on 2.5 tons of grain – 0.34 tons from hectare. Thus, the aim of our research was to develop methods of growing high yielding quality grain of different types of wheat adapted to the conditions of forest-steppe in the Volga region.

The formation of the yield by crops is influenced by many factors and the state of the plant itself. The purpose of the study is to determine the efficacy of the preparation Zircon in combination with mineral fertilizers and seed protectant for the formation of spring wheat yield. The research is conducted at the experimental field of the Kazan State Agrarian University in years 2016-2018, with Yoldyz, a regional variety of spring wheat. Seed treatment with growth regulator Zircon increases yield on the background without fertilizers amounts to 0.14 t/ha and 0.21 t/ha without fertilizers and with fertilizers, respectively. Seed treatment with growth regulator Zircon and protectant Dospekh 3 provides the yield increase of 0.18 t/ha without fertilizer additions. When fertilizers are added yield increases by 0.29 t/ha and 0.35 t/ha, for N61P55K55 and N120P126K97, respectively. In this case, return of fertilizers of the grain per 1 kg D. V. makes fertilizers N61P55K55 increase to 7.89 kg, while N120P126K97 amount to 5.57 kg.

Improving the efficiency of fertilizers used, growth stimulants, taking into account the active phases of culture development remains relevant. The purpose of our study is to identify the impact of calculated doses of nutrients, pre-sowing seed treatment and treatment of vegetative plants with a growth stimulant on the productivity of spring soft wheat. Field experiments and laboratory studies were conducted in 2019-2021 on gray forest soils of Agrobiotechnopark LLC of Kazan State Agrarian University. The scheme of the field experiment involved the study of the following options: mineral fertilizers (factor A) - without fertilizers (0); calculated dose for grain yield 3.5 t/ha (N36P23K35); calculated dose for grain yield 4.5 t/ha (N94P83K77); growth stimulants (factor B) - seed treatment with Vial Trust 0.5 l/t; seed treatment with Vial Trust 0.5 l/t + spraying of plants in the tillering phase Stimax Growth 1 l/ha; seed treatment with Vial Trust 0.5 l/t and Stimaks 0.5 l/t + spraying of plants in the tillering phase Stimaks Growth 1 l/ha; seed treatment with Vial Trust 0.5 l/t and Stimax 0.5 l/t + spraying plants in the tillering phase Stimax Growth 1 l/ha + spraying plants in the booting phase Nutrivant Plus 2 kg/ha. The survival of plants on an unfertilized background was 57.7...62.0%, N36P23K35 - 62.5...67.2%, N94P83K77 - 71.8...79.8%. The complex effect of the disinfectant and growth stimulants in the treatment of seeds and plants in the tillering and booting phases ensured an increase in the survival of plants on an unfertilized background by 4.3%, against the background of N36P23K35 - by 4.7%, against the background of N94P83K77 - by 8.0% . The average wheat yield of the Ulyanovska 105 variety on an unfertilized background was 3.21 t/ha, N36P23K35 - 3.69 t/ha, N94P83K77 - 4.28 t/ha. The combined use of growth stimulants in the treatment of seeds and plants in the tillering and booting phases was accompanied by an increase in wheat yield by 4.7, 5.1 and 7.0%, respectively.

The results of two–year (2018–2019) studies on the effect of various seeding rates and nutritional backgrounds on the yield and grain quality of two types of spring wheat – soft wheat and emmer wheat (spelt) – are considered. The agrochemical characteristic of the gray forest soil of the experimental plot is as follows: the humus content in the layer of 0–20 cm was 2.9–3.4 % (Tyurin method), mobile phosphorus amount was 176–241 mg, exchange potassium amount was 77–109 mg/kg of soil (Kirsanov method). The degree of saturation with bases was 85.2–87.7 %, the pH of the salt extract was 5.6–5.8. Agrometeorological conditions of 2018–2019, on the whole, met the requirements for early spring crop seeding, HTC (hydrothermal coefficient) was 0.85–1.2. Two levels of mineral nutrition were studied in the experiment (natural background, without fertilizing, NRK for the planned grain yield of 3 t/ha), four seeding rates against each nutrition background: 4, 5, 6 and 7 million germinating seeds per 1 ha. The seedling completeness in both types of wheat over an average of 2 years depended on the seeding rate, regardless of the background of nutrition. In soft wheat of Ulyanovskaya 105 variety, against a natural background, with an increase in the sowing rate from 4 to 7 million germinating seeds per ha, the seedling completeness decreased and amounted to from 82.5 to 76.3 %, in spelt, it was 84.7–78.6 %. On a fertilized ground it was, respectively, 83.4–78.0 and 84.1–77.6 %. Good preservation of plants in both types of wheat from the number of sown seeds and seedlings was noted when the sowing rate was reduced from 7 to 4 million: without fertilizer 82.6–88.5 % in common wheat and 83.5–90.4 % of spelt. On a fertilized ground it amounted, respectively, to 84.3–90.5 and 86.5–92.3 %. Changes in nutritional background by introducing calculated doses of mineral fertilizers for all options with seeding rates on average for 2018–2019 yielded an increase in soft wheat by 0.94 tons of grain per hectare and by 0.61 tons of spelt. The highest conversion efficiency of fertilizers at a sowing rate of 6 million in common wheat was 8.1 kg of grain per 1 kg of a.a., for spelt at a sowing rate of 4 million the figure was 5.6 kg per 1 kg of a.a.