No abstract

Reverse drying is acknowledged to be widely used in the woodworking industry, and in corn cob drying, but it is hardly used for drying grass and cereal seeds. It can be explained by insufficient research into the matter. It is noted that the reversible dryer operation is characterized by the duration of one-direction blowing and the permissible temperature of the drying agent. It has been found that a temperature increase in the drying agent is crucial for dryers designed for processing small-seed crops, since they operate at lower temperatures compared to those designed for cereals. (Research purpose) To determine the effectiveness of a reversible grain dryer that lies in reduced unit costs and increased productivity, as well as the duration of blowing in one direction and the drying agent allowable temperature. (Materials and methods) The main parameters characterizing the operation of a reverse grain dryer have been determined as follows: the duration and permissible temperature of grain heating, the indicators of the one-direction blowing mode and the permissible temperature of the drying agent. It has been found that the intensification of the reverse drying process can be achieved by an increase in the drying agent temperature compared to drying in the one-direction blowing mode, possible due to a higher permissible temperature of seed heating. (Results and discussion) The economic testing of a reversible dryer proved its efficiency in terms of an increase in productivity, a decrease in the specific heat consumption as well as the seed drying non-uniformity below the norm. It is emphasized that an increase in the maximum permissible grain temperature by about 2 degrees Celsius corresponds to a 4-6-degree rise in the drying agent temperature and a 10-12 percent increase in the dryer productivity. (Conclusions) A reverse dryer is proved to be more efficient compared to a traditional one that lies in a 13-percent increase in productivity and a 10-percent decrease in the specific heat consumption, as well as the seed drying non-uniformity below the norm. It has been found that the duration of one-direction blowing mode in a reversible grain dryer was 0.3 hours. It has been determined that compared to the traditional drying, the maximum temperature of the drying agent in the reverse-mode drying is calculated based on the seed permissible temperature, that is to be 2-3 degrees higher than the maximum permissible one. According to the findings, it is 57 degrees Celsius for ryegrass seeds.

Analyzing agro-climatic conditions for the period of 1981–2020 has revealed a tendency for local climate warming under the condition of its aridization in the territory of the Central region of the Russian Non-Chernozem zone, and the new northern borders for soybean growing in the region have been marked. The isotherm of the sum of active temperatures has been established to have shifted towards high latitudes by 150–200 km. The values of the sum of active temperatures have increased from 1700–2200 °С to 1950–2400 °С, while the amount of precipitation during the growing season has decreased by 20–40 mm on average, from 270–280 mm to 190–230 mm. Three agro-climatic subzones—northern (NAS), central (CAS) and southern (SAS)—have been identified, each characterized by similar temperature and humidity conditions during the growing season. Thus, in the northern agro-climatic subzone, the sum of temperatures during the growing season is 2000–2200 °C, the HTC (hydrothermal coefficient) is 1.4–1.7, and the sum of precipitation is 285–295 mm; in the central subzone, the sum of temperatures is 2200–2400 °C, the HTC is 1.1–1.4, and the sum of precipitation is 265–285 mm; in the southern one, the sum of temperatures is 2400–2600 °C, the HTC is 0.7–1.1, and the sum of precipitation is 255–265 mm. Along with the northern ecotype varieties recommended for this zone, the vegetation features of early maturing soybean varieties of other ecological types—southern and Far Eastern—were studied. As a result of the agro-ecological analysis of early maturing soybean varieties, it has been found that the soybeans belonging to the group of very early or early maturing with a determinant type of growth are recommended for cultivation in the northern agro-climatic subzone of the Central region of the Non-Chernozem zone; the soybean varieties belonging to the group of very early or early maturing with a determinant or semi-determinant type of growth—in the central zone; the soybean varieties belonging to the group of very early or early maturing with a determinant, semi-determinant, and indeterminant type of growth—in the southern zone. Considering the variety characteristics and the agro-ecological tests conducted, it has been found that the northern ecotype varieties can sustainably ripen in all agro-climatic subzones in the Central region of the Non-Chernozem zone, the southern and the Far Eastern varieties—in the central and the southern zones.