Prospects for the use of calcium ammonium nitrate on acidic soils of the Non-Black Earth Area

. The results of the effectiveness of the application of calcium ammonium nitrate (CAN) in winter wheat crops of the "Moskovskaya-39" variety on the dark-gray forest, heavy-loamy soil in the Ryazan region is presented. The advantage of CAN-a a universal form of nitrogen fertilizer, which has a neutral reaction and creates optimal conditions for feeding plants with nitrogen in the zone of its application, where the main mass of plant roots is located, is revealed. Along with nitrogen, fertilizer contains calcium and magnesium, which are essential for the formation of winter wheat productivity, the exchange of carbohydrates and proteins. In the field experience with winter wheat on soils not saturated with bases, the results were obtained, indicating the effectiveness of a physiologically neutral form of nitrogen fertilizer, which showed an advantage over physiologically acidic fertilizer - ammonia nitrate. Dynamics of the formation of the productivity of sowing showed that the area of leaves reached the maximum sizes by the flowering phase of 61.6-76.6 cm 2 /plant, the largest value of the indicator 76.6 cm 2 /plant was in the variant with the use of CAN feeding at a dose of 54 kg/ha of nitrogen. The use of CAN provided a reliable increase in the harvest of winter wheat grain in comparison with ammonium nitrate. The grain harvest in the experiment was 63.7 - 67.1 cents per hectare, statistically close were the values of yield in variants using CAN in doses of 68 and 54 kg/ha of nitrogen, the increase in the harvest was 3.8-5.3% respectively. The creation of optimal conditions for winter wheat during the growing season was accompanied by an improvement in the quality of the grain, in comparison with the variant

chemical properties of the soil. This property allows the use of CAN on various types of soils, especially effective on sod-podzolic medium and slightly acidic soils [1].
The indisputable advantage of CAN is the presence in its chemical composition, in addition to nitrogen, of calcium and magnesium carbonates, which cause an increase in the efficiency of non-root fertilization of crops on both acidic and alkaline soils, as well as on soils of light granulometric composition (sandy, sandy loam) and saline [2,3]. The use of CAN not only increases the supply of plants with such elements of mineral nutrition as nitrogen and calcium but also contributes to the preservation of soil fertility and the creation of sustainable agriculture.
In the development of grain farming, the priority direction is to increase the production of winter wheat grain and improve its quality, this is the most realistic way to increase the resources of food and feed protein [4,5]. One of the main and controlled methods for improving the technology of winter wheat cultivation is the scientifically based use of mineral fertilizers, taking into account soil and climatic conditions and the physiological needs of plants, which makes it possible to significantly increase the yield and harvest of plant proteins [6][7].
Along with nitrogen, phosphorus, and potassium, an important physiological role of calcium for the formation of winter wheat productivity has been established. Calcium participates in the metabolism of carbohydrates and protein substances, provides favorable conditions for the development of the root system, and actively affects the protoplasm and its colloidal-chemical properties [8][9].
Winter wheat in the Russian Federation occupies a leading position among grain crops, including, in comparison with spring wheat, and is characterized by a higher and more stable yield. Among the grain crops, winter wheat is the most demanding for the level of mineral nutrition. It consumes about 10 kg of calcium per 1 ton of grain, and there may be a lack of it due to the increased yield and increased removal from the soil [10]. When there is a lack of calcium, as a rule, there is a slime of root cells, the absorption of nutrients from the soil is disrupted, the growth of leaves is delayed, they appear chlorotic -light yellow spots, which leads to the death of leaves [11].
When improving the fertilizer system, the issues of plant nutrition with calcium were not given much importance, and mainly highly concentrated species containing mainly N, P, K are used [12]. This leads to an increase in calcium in agrocoenosises, including in chernozems, which will naturally have a negative impact on the yield and quality of winter wheat grain [13].
Against the background of the use of highly concentrated unbalanced mineral fertilizers, extremely low application of organic and lime fertilizers, a negative balance of calcium in the soil is formed [14]; therefore, the search for methods of activating physiological processes that provide an increase in protein synthesis in plants and an increase in protein content without reducing grain productivity is not only relevant but also promising [15].
The purpose of the research was to study the effectiveness of the use of various doses of CAN in non-root top dressing on winter wheat crops of the "Moskovskaya-39" variety on the dark gray forest, heavy loamy soil in the Ryazan region. Agrochemical indicators of the site's soil are presented in Table 1. The scheme of the experiment was built according to the method of organized repetitions, the repetition is 4-fold. In the experiment, a comparative assessment of the effectiveness of CAN (nitrogen content of 27%) with ammonium nitrate (nitrogen content of 34%) was carried out. As background, in autumn (NPC)60 fertilizers were introduced in the form of nitrophosk NPK =16-16-16 (375 kg/ha by weight). Mineral fertilizers were applied for pre-sowing cultivation of KPS-4 with simultaneous embedding according to the variants. Nitrogen fertilizing with ammonium nitrate and CAN was carried out after the fixation of the VNVV (the time of the beginning of the spring vegetation of winter wheat). The agricultural technology of winter wheat cultivation corresponded to the zonal recommendations. All studies, including the assessment of the quality of the grain of the resulting crop, were carried out under GOST. Sowing of winter wheat "Moskovskaya-39" was carried out with the SZ -5,4 A -0,6 seeder, according to the generally accepted technology of cultivation of the crop. The seeding rate is 5.5 million/ha of germinating grains. At the time of sowing, the soil moisture in the layer of 0-30 cm was 16.8%.
The growth and development of winter wheat were greatly influenced by the climatic conditions of the 2019-2020 experiment. In general, they were favorable for their growth and development.
Winter wheat plants in the fall of 2019 developed in conditions of high temperatures and lack of moisture. In total, 78.9 mm of precipitation fell during the autumn growing season, which is 15% of the long-term average values. Despite such conditions, visually, the crops in the autumn period were assessed as good. The scheme of the experiment consisted of 4 variants: Experience variants

Discussion of research results
Spring nitrogen fertilization had a great influence on tillering, increasing the number of stems with an ear ( Table 2). Wheat plants on the variants with top dressing formed a more powerful root system and were bushier. There were no differences in overwintering in the experimental variants Questions of the nitrogen regime of soils, diagnostics of the need of plants for nitrogen are not sufficiently studied. The main source of nitrogen nutrition of plants in the field is nitrate and ammonia nitrogen ( Table 3). As a result of the conducted studies, it was found that the reserves of nitrate and ammonium nitrogen in the soil in the variants vary slightly, but no significant differences were found. CAN is a physiologically neutral fertilizer, so on acidic soils, it may have advantages over the widely used, physiologically acidic ammonium nitrate. The study of biometric indicators of winter wheat plants showed that the weight of the aboveground part of the plants did not differ much in the tubulation phase in the experimental variants; however, by the time of flowering, better plant development was noted in variants 2, 3, and 4. The height of plants in the same variants increased significantly, by 15.5 cm, 22.4, 9.7 cm, respectively, compared to the variant where ammonium nitrate was used. The determination of the leaf surface area by the development phases showed that both forms of nitrogen fertilizers had a positive effect on the value of the indicator. Almost before the phase of milk ripeness, there was an increase in the leaf apparatus in all variants, which contributed to the intensive consumption of batteries.
It was found that the assimilation area in the tubulation phase was 42.  (Table 6).  In the phase of milk ripeness, the leaf area decreased due to the drying of the leaf tips, but there is a tendency to increase the leaf area in variants No.  Table 7). The use of various nitrogen fertilizers did not affect the phosphorus content. The  (Table 8). The change in the values of the main elements of the structure of the winter wheat crop, due to the use of nitrogen fertilization by various types of fertilizers, affected the final yield of winter wheat grain (Table 9).  The assessment of the quality of wheat grain showed that in the conditions of 2020 when using different types of nitrogen fertilizers, there were no significant differences in the content of st`arch, protein, gluten, and the value of IDC; however, the grain nature in variants 2, 3, and 4 decreased (Table 10). Evaluation of the effectiveness of CAN on winter wheat crops of the "Moskovskaya-39" variety showed that the highest gross profit of 40,702 rubles was obtained in the 2 nd variant, where CAN was applied to top dressing at a dose of 68 kg/ha of nitrogen. In the 3 rd and 4 th versions of the experiment, where CAN was used at a dose of 54 kg/ha of nitrogen and VRU, a similar gross profit was obtained -39022 and 39324 rubles, respectively. Profitability, also the greatest-154.2% was noted in the conditions of a top dressing of CAN in the maximum dose in the 2 nd variant. The reduction of the dose of CAN in the 3 rd variant and the use of VRU provided similar profitability indicators -144, and 143.1%.

Conclusion
A comparative assessment of the effectiveness of calcium ammonium nitrate with traditional nitrogen-ammonium nitrate on winter wheat crops of the "Moskovskaya-39" variety on dark gray forest heavy-loamy soil indicates that CAN with non-root fertilization of the crop during the growing season had an advantage in its effect on plant development and the formation of grain yield. The grain yield in the variants with the use of CAN at doses of 68 and 54 kg/ha of nitrogen was statistically similar in value, the increase was 3.8-5.3 % compared to the variant where ammonium nitrate was used.