Sowing Period Research Articles

Problems and effectiveness of breeding of winter wheat varieties with increased environmental stability

Aim. The search of adaptive response peculiarities to adverse environmental factors is an important condition of development of varietal technologies and control of adaptive potential of winter wheat varieties. Methods. The studies were carried out in accordance with the field test methodology. The wheat varieties of different types of growing, different genetic and ecological origins were studied. Results. The alternative variety Clarisa and the new universal varieties of winter wheat Perlyna, Askaniyska, Askaniyska Bereginya were characterized by the highest yield at different times of spring vegetation recovery. Thus, on average over the years of research, they exceeded the standard variety of Kherson Bezosta by 0.51–1.27 t/ha in terms of yield, and under unfavorable conditions of the late recovery of spring vegetation, their advantage was at the level of 0.58–1.34 t/ha. Conclusions. For stable production of high-yielding winter soft wheat grain, use new varieties of the universal type Askaniyska, Askaniyska Bereginya, Perlyna and alternative types Clarissa, Solomia for different agrophones for late sowing periods according to different predecessors.

ВСХОЖЕСТЬ, ЭНЕРГИЯ ПРОРАСТАНИЯ И ПРОДУКТИВНОСТЬ РЫЖИКА ОЗИМОГО

The current structure of arable land in the Volgograd region leads to a number of problems in our agricultural complex, which must be solved through expanding the set of crops. In the current situation, winter ginger may turn out to be a real alternative to sunflower, partially replacing it in the group of oilseeds. In this regard, it is extremely important to improve the elements of the technology of growing winter ginger in relation to the conditions of light chestnut soils of the Volgograd region. The aim of the research was to study the effect of sowing dates and growth regulators on the productivity of winter ginger in the subzone of light chestnut soils of the Volgograd region. Field experiments were conducted in 2014-2017 in the conditions of the UNPC of the Volgograd State Agrarian University "Gornaya Polyana", Volgograd. Laboratory germination of winter ginger seeds of the Penzyak variety before sowing on average for 2014-2016 in the variant without treatment with growth stimulants was within 95.3%. On the Humat + KalMag variant, it was 1.8% more. In the variant with Humate, the laboratory germination was 2.7% higher compared to the control. In the variant treated with Zircon, laboratory germination was 3.0% higher compared to the control. And the highest laboratory germination was observed on the variant with the Epin-extra preparation and amounted to 99.4%, thereby exceeding the laboratory germination of the variant without growth stimulants by 5.1%. The field germination of winter ginger by sowing dates was not the same and on average over 3 years of research ranged from 62.0% at the first sowing period to 68.2% at the third term. The influence of growth regulators on field germination turned out to be more significant. Zircon increased field germination from 5 to 8.2%, and Epin-extra from 7.3 to 8.2%. Over the years of research, the winter hardiness of winter ginger varied from 66.1 to 77.4%. The maximum yield of winter ginger on average for 2015-2017 was formed on option 3 of the sowing period (September 17-20) and was equal to 2.26 t/ha. The minimum yield for an average of three years of research was formed on the control variant without seed treatment with growth regulators at the first sowing period and amounted to 1.57 t/ha.

Effects of prostaglandin administration after farrowing on milk output, vaginal discharge, and mastitis during the early postpartum period in sows under field conditions

Effects of prostaglandin administration after farrowing on milk output, vaginal discharge, and mastitis during the early postpartum period in sows under field conditions

Evaluation of the productivity of maize (ATP) under different sowing dates in the western highlands of Cameroon

This study aims to assess the effects of three sowing dates on the growth and yield of maize. The trial was conducted at the Teaching and Research Farm of the University of Dschang in Bansoa (Penka-Michel) over two growth cycles: 2020 and 2021. The experiment was arranged in a randomized complete block design. Treatments, replicated three times, included a control (T) and three levels of fertilizer input: mineral fertilizer (E), organic fertilizer (F), and organo-mineral fertilizer (EF). The maize variety used was the Acid Tolerable Population (ATP). Sowing occurred sequentially on March 30, April 10, and April 20. Daily rainfall data were collected using a graduated cylinder rain gauge. Observations focused on growth and yield parameters at different sowing dates. The results obtained indicate that maize responded significantly to different sowing dates (p < 0.05). Fertilizer application also positively influenced growth compared to the control. The tallest plants were observed in the F treatment sown during the first date (300 cm). Similarly, the collar diameter followed the same trend, with the F treatment measuring 3.43 cm compared to 2.14 cm for the control, indicating significant differences. Yield results showed the first sowing date > second date > third date. The highest yield was achieved with the EF treatment during the first period (6985 kg/ha), compared to the control during the third period (2009 kg/ha). Within each period, the yield results followed the order: EF > E > F > T. Organic fertilizers alone also produced favorable results compared to the control. Given the current climatic conditions and the results obtained, maize sowing conducted in the first sowing period (March 30) with organo-mineral fertilizer would likely result in optimal grain yield.

The effect of sowing time on productivity of new maize hybrids

The relevance of the current study is due to the fact that global warming in the south of Russia has significantly moved forward the onset of the hot period, especially in areas of risky farming. Sowing at the previously recommended scientifically based optimal time no longer guarantees stable yields of maize. Based on this, the purpose of the study was to determine the effect of the sowing time of new promising maize hybrids of our own breeding on productivity and yield structure elements in the steppe part of Kabardino-Balkaria. The study was carried out in field trials on the field of the research and production site of the Institute of Agriculture of the KBRC of the Russian Academy of Sciences in 2019–2021. In general, during the years of study, weather conditions were typical for the steppe area of the KBR. As a result, there was determined that the optimal sowing time for maize hybrids was the second decade of April. When sowing at this time, there was identified productivity improvement and an increase in the values of yield elements. On the contrary, sowing in the third decade has shown a decrease in the values of these indicators in all studied samples. During the second sowing period, there was the greatest productivity decrease among the late-maturing hybrids ‘Karat SV’, ‘Terek’ and the hybrid population ‘Kabardinskaya 3812’ by 1.4; 1.5 and 1.8 t/ha, respectively. The middle-early hybrid ‘Maisky 260 MV’ has shown a smaller decrease by 0.7 t/ha. During the first sowing period, number of ears per 100 plants increased by 4–11 pieces. The ears were better grained with 5–60 pieces of the excess over the second period. The weight of one cob during the first sowing period ranged 105–120 g on average, which was 9–22 g more than the same indicator during the second sowing period.

Variability in the responses of rice ecotypes to elevated CO2 based on data from FACE studies in China and Japan: Implications for climate change adaptation

Elevated CO2 increases rice yields, and the response level varies across locations and genotypes. Previous analyses of genotypic variations from diverse Free-Air CO2 Enrichment (FACE) studies lacked specificity, limiting their applicability in simulating the responses of crop growth to elevated CO2. Using meta-analysis approach and the ORYZA (v3) model with historical and projected climatic data, this study evaluated the differences in the responses of rice ecotypes to elevated CO2 and identified adaptive measures. Meta-analytical findings indicated that Chinese inbred indica (indicai) and hybrid indica (indicah) rice exhibited comparable yield response rates (28.4% and 31.1%, respectively) to elevated CO2, surpassing those of Chinese japonica rice and Japanese indicai and japonica rice. Achieving higher adaptation to elevated CO2, exemplified by Chinese indicah rice, necessitates the consideration of balanced yield components, with individual contributions to yield responses ranging from 9.8% to 36.2%. This study highlighted the susceptibility of japonica rice to adverse effects of maximum temperatures on yield component responses to elevated CO2 compared to indicai or indicah rice. Strategic adjustments in sowing dates can enhance rice production under climate change, with high-response genotypes benefiting more from optimal sowing periods. Furthermore, for genotypes with less responsiveness to elevated CO2, augmenting nitrogen application in conjunction with sowing date adjustments was beneficial for yield optimization. This research not only advances our understanding of the diverse adaptation strategies of rice genotypes under varying climatic conditions but also enhances the precision of crop growth simulations by accounting for the varied responses to CO2 enrichment. These insights are pivotal for developing targeted breeding and management practices aimed at enhancing climate resilience in rice production.

An improved crop calendar model for winter wheat incorporating vernalization and winter survival to project changes in phenology

Crop phenology and associated crop calendars are necessary for designing breeding goals and for developing effective management practices. Winter wheat is a representative biennial, the cultivation schedule of which is constrained by winter climate conditions, particularly the processes of vernalization and winter survival. Here, we present improvements to a rule-based crop calendar model by incorporating these factors so that it can be used to accurately estimate the phenological events of winter wheat from daily meteorological data. We tested the improved model in Hokkaido, the northernmost Japanese island, which is characterized by seasonal snow cover and a wet summer. The results confirmed that implementing these factors contributed to accurate estimates of peak occurrence dates of winter wheat phenological events. Furthermore, we applied the improved model to simulate wheat phenology under 2 K and 4 K warmer scenarios. The results showed a delayed sowing period up to approximately one month and slight advancements in both flowering and harvesting, leading to a shorter growth period. While this shortened period may be largely compensated by a decrease in the snow-covered period, the shifts in the vegetative and reproductive phases may modify sink-source balance of wheat. We also assessed the risks of pollination failure and preharvest sprouting, both of which are associated with the timing of precipitation, based on the number of rainy days around flowering, and the incidence of precipitation over two consecutive days around the time of harvesting. Our simulations suggested increased risk of pollination failure and reduced risk of preharvest sprouting, leading to an increase in the probability of crop failure. These findings underscore the importance of implementing adaptation measures to mitigate precipitation-related risk under future climates. Further, the findings provide valuable insights for winter wheat breeders and agronomists, thereby facilitating crop production adaptation.

New lines of the Triticum Spelta in Sought Dagestan

Few people know about the existence of such a grain crop as spelt and its benefits for human health. This is a unique product with a balanced vitamin and mineral composition, surpassing even soft wheat in the content of valuable substances. The center of origin this crop is the Mediterranean countries. The first mentions of spelled are found in Ancient Egypt, Babylon, Greece, Turkey and Armenia. After a long period of oblivion, spelled Triticum dicoccum (Schrank) Schuebl reappeared in the crops of European countries and is actively cultivated in Iran, India, Turkey, the USA, and in Russia – in the Krasnoyarsk region, Omsk region, Tatarstan, Dagestan. The absence of gene-modified varieties and the complex of beneficial properties of its grain are interesting for the use of this crop. Spelled grain contains more than 18% protein and has a higher content of fiber, Zn, Fe and Mn compared to other types of wheat. Products made from spelled grain are use as dietary products. Using spelled as food reduces the risk of cardiovascular diseases and a number of cancers. Today, the main suppliers of spelled cereal are Iran, India, Turkey, USA, Armenia, and Dagestan. Literary information about the regions with soil and climatic conditions appropriate for the cultivation of this crop is rather scarce. The morpho-biological study of spelled in connection with economically valuable traits and the identification of promising samples for cultivation in a particular region is relevant. Since 2013, the Dagestan Experimental Station has been conducting laboratory and field evaluation of new naked spelt lines, created by Professor Vladimir Dmitrievich Kobylyansky (St. Petersburg, VIR). These lines were created by selection hybrids(F12) from crossing of spelt (T. dicoccum) and hard wheat varieties (T. durum Desf.) In 2016, 2 best ones with glassy grain were selected and were included in the control nursery for a comprehensive study under the winter sowing period of spring grain crops accepted in the region. The samples were studied for early maturite, resistance to fungal diseases, lodging and yield. The results of a three-year (2020–2022) study of the two selected forms were obtained and the contribution of various traits to the formation of the crop was determined.

The effect of sowing dates and sowing rates of wintering peas when cultivated in the southern part of the Rostov region on the economic efficiency of grain production

The current paper has presented the results of field trials carried out at the FSBSI “ARC “Donskoy” in 2019–2021 to study individual elements of cultivation technology (sowing dates, sowing rate) of wintering peas. The purpose of the study was to estimate the effect of sowing dates and sowing rates of wintering peas when cultivated in the southern part of the Rostov region on the economic efficiency of grain production. When cultivating wintering peas in the southern part of the Rostov region, the largest shares of costs have been spent on pesticides and seeds and were, respectively, 43.7–38.4 % and 25.4–35.9 % for the variety ‘Zimus’; 44.4–39.2 % and 23.9–34.3 % for the variety ‘Fokus’; 45.9–41.0 % and 20.7–30.6 % for the variety ‘Faeton’. The maximum gross income of 42,370 rubles/ha from the sale of wintering pea grain was obtained from the variety ‘Fokus’ in the third sowing period in the variant with a seeding rate of 1.4 million pcs. of germ. seeds/ha. The maximum conditional net income of 16,798 rubles/ha wasnoted for this variety in the second sowing period with a seeding rate of 1.2 million pcs. of germ. seeds/ha. The minimum production cost of 11,052 rubles/t was obtained from the variety ‘Fokus’ in the third sowing period with a seeding rate of 1.0 million pcs. of germ. seeds/ha, the maximum level of profitability of 72 % was noted in the same option. For the variety ‘Faeton’, grain was sold on 37,430 rubles/ha in the first sowing period at a seeding rate of 1.2 million pcs. of germ. seeds/ha. Also in this option, the highest conditional net income was 14347 rubles / ha with the lowest cost of production of 11717 rubles/ton and the maximum level of profitability of 62 %. For the variety ‘Zimus’, the maximum gross income from grain sales was 41420 rubles/ha with a seeding rate of 1.4 million pcs. of germ. seeds/ha in the second sowing period. In the same option, the highest conditional net income was 14423 rubles/ha, the lowest cost of production was 12384 rubles/t with the highest level of profitability of 53 %.

Effect of Sowing Date, Scheme and Nutritional Conditions on Glycine Height Grown for Grain

The article presents the results of the research conducted on the influence of cultivation factors on the growth of the Biyson variety of soybeans in 2018-2020 in the Absheron region to obtain the grain harvest. In the studies, when the optimal sowing period of soybean was carried out in the 3rd decade of April, in all three sowing schemes, the highest indicator of the height of the plant was at the N60P40+15 tons of manure option. At the mentioned version, the height of the plant, depending on the sowing scheme, was 2.8-4.4 cm at the stage of 4-5 true leaves, 6.2-11.1 at the stage of branching, 4.9-15.9 cm at the stage of budding-flowering, 4.2-14.4 cm in pod formation stage and at the full maturity stage, it was 5.6-26.3 cm taller than the non-fertilized version. This has created conditions for more branching of the plant and the formation of beans, which, in turn, have a substantial effect on the increase in productivity.

Impacts of Fiber Supplementation in Sows during the Transition Period on Constipation, Farrowing Duration, Colostrum Production, and Pre-Weaning Piglet Mortality in the Free-Farrowing System.

This study investigated how dietary fiber supplementation during the transition period in sows affects constipation, farrowing duration, colostrum production, milk yield, and pre-weaning piglet mortality in the free-farrowing system. A total of 92 Landrace × Yorkshire sows and their 1272 offspring were included in the study. Sows were divided into two groups by parity: control (n = 41) and treatment (n = 51). The control group was fed a standard lactation diet 7 days before farrowing, whereas the treatment group received the same diet with 75 g/day of a dietary fiber supplement. The dietary fiber content analyses were 4.30% and 5.53% in the control and treatment groups, respectively. Sows were fed with 3.89 ± 0.92 kg per day with a diet containing 17.8% crude protein, 3732 kcal/kg of metabolizable energy, and 1.1% lysine. Parameters including farrowing duration, litter characteristics, and the fecal condition of sows were measured. Piglet mortality rates were recorded at 3, 7, and 21 days of lactation. Sows had an average farrowing duration of 216 ± 159 min, with litter sizes of 13.8 ± 4.2 piglets per litter, and a 7.4% stillbirth rate. The treatment group showed a lower constipation rate compared to the control group (17.6% vs. 46.3%, p = 0.003). Farrowing duration did not significantly differ between groups, but the treatment group experienced a 43.6 min shorter duration. In sows with litter sizes of ≥16 piglets per litter, the farrowing duration for sows in the treatment group tended to be shorter than that of the control groups (202.0 ± 37.9 vs. 287.5 ± 41.3 min, p = 0.115). The mean colostrum intake of piglets in the control and treatment groups averaged 424.0 ± 13.7 g and 421.8 ± 12.6 g, respectively (p = 0.908). Likewise, the milk production of sows from Days 3 to 10 and from Days 10 to 17 of lactation in the treatment group (7.34 ± 0.27 and 8.76 ± 0.43 kg/day, respectively) did not differ from that of the control group (7.85 ± 0.30 and 9.55 ± 0.47 kg/day, respectively, p > 0.05). Pre-weaning piglet mortality was slightly lower in the treatment group (13.4% vs. 17.3%, p = 0.085). Across groups, piglet mortality rates within 3, 7, and 21 days were 10.3%, 11.9%, and 15.4%, respectively. Piglets with a ≤200 g colostrum intake had a higher pre-weaning mortality compared to those with a higher intake (p < 0.05), except for the 201-300 g intake (p = 0.472). In conclusion, introducing dietary fiber to sows during the transition period reduced constipation and tended to decrease farrowing duration, especially in sows with large litters. Additionally, it lowered pre-weaning piglet mortality by 3.9% in the free-farrowing system. Nonetheless, providing sows with a 75 g/day dietary fiber supplement for only 7 days before farrowing was not enough to enhance colostrum and milk production, nor did it lead to an increase in piglet colostrum consumption.

Study on spring drought in cold and arid regions based on the ANOVA projection pursuit model

Due to the influence of snow cover and soil freeze–thaw processes in the early spring, the characteristics of spring drought in cold regions are different from those in other regions. This paper takes Qiqihar, a cold and semiarid grain production area in Northeast China, as the study area. Based on factors such as snow cover in the early spring period and precipitation, temperature, evapotranspiration, and soil moisture during the spring sowing period, a projection pursuit model with analysis of variance (ANOVA PPM) was used to analyze the spatiotemporal variation characteristics of regional spring drought. For the ANOVA PPM, based on the grouping of the projection points, local aggregation is measured by the mean square within groups, and overall dispersion is measured by the mean square between groups, thus achieving comparability and balance between overall dispersion and local aggregation. The spatial analysis of spring drought showed that, from a spatial perspective, there were significant spatial differences in spring drought in different subregions, and spring drought was closely related to latitude, with significant differences occurring at different latitudes. The northern region is relatively light, while the central and southern regions are more severe. From a temporal perspective, there are significant differences in spring droughts between different decades (1980 s, 1990 s, 2000 s and 2010 s). Overall, spring drought first intensifies and then decreases.

Yield indexes and effective productivity in corn hybrids of different fao groups for different sowing periods in the Northern Steppe of Ukraine

Yield indexes and effective productivity in corn hybrids of different fao groups for different sowing periods in the Northern Steppe of Ukraine

ВЛИЯНИЕ ПРИЕМОВ ВОЗДЕЛЫВАНИЯ НА УРОЖАЙНОСТЬ И ВОДОПОТРЕБЛЕНИЕ ГОРОХА В УСЛОВИЯХ РОСТОВСКОЙ ОБЛАСТИ

Purpose: to identify an effective combination of primary soil tillage methods, fertilizer background, water consumption features at different sowing dates and their influence on the yield of new pea varieties in Rostov region. Materials and methods. The research was carried out in 2022–2023 at the experimental stationary of the scientific center. The following were studied: basic soil tillage methods (plowing, combined, chiseling) (factor A); fertilizer backgrounds: 1) without fertilizers, 2) Р₄₀K₄₀, 3) P₆₀K₆₀, 4) P₈₀K₈₀, 5) N₁₅Р₄₀K₄₀, 6) N₃₀P₈₀K₈₀ (factor B). Sowing was carried out in two stages. Soils are ordinary chernozem. Results. Higher yields were obtained in the variants of the 1st sowing date, regardless of cultivation and fertilizers. The increase was 6.3–6.8 % for the Donets and 6.9–8.4 % for the Amulet varieties, compared with the data for the 2nd term. A decrease in yield was noted with combined and chisel tillage, regardless of the fertilizer background and sowing dates; it was 6.0–6.3 and 5.2–5.3 % for the Donets and Amulet varieties, respectively; 4.9–5.2 and 3.5–4.7 %, compared with plowing (factor A). The highest pea yield according to factor B was provided by the N₃₀P₈₀K₈₀ variant: 3.03 and 2.86 t/ha for the Donets varieties, 2.56 and 2.39 t/ha for the Amulet varieties. The yield increases reached 0.89–0.93 t/ha (44.3–45.2 %) and 0.67–0.71 t/ha (38.3–38.9 %), respectively, compared to the control. The difference in average yield between the P₈₀K₈₀ and N₃₀P₈₀K₈₀ variants did not exceed 0.09–0.13 t/ha for the Donets variety and 0.03–0.06 t/ha for the Amulet variety. Conclusions. The best average yield was obtained in the variant with plowing and N₃₀P₈₀K₈₀ nutrition at the first sowing period in 2023, amounting to 3.72 t/ha for the Donetsk variety and 2.91 t/ha for the Amulet variety. The lowest water consumption coefficient of peas was also noted here – 804 m³/t.

Change of available soil moisture reserves in agrocenoses of winter wheat in short rotation crop rotations

The article presents the results of changes in available soil moisture in winter wheat crops in four short-rotation crop rotations. The research was carried out during 2012-2021 at the experimental field of the Belotserki National Agrarian University of the Kyiv region. The soil of the experimental field is a typical chernozem with a low humus content of average loamy humus in the 0–30 cm soil layer of 3,7–3,9 %. Four short-rotation crop rotations were studied (sunflower saturation 10 %); cereal grain (sunflower saturation 20 %); specialized seedbed (sunflower saturation 30 %); rowing (sunflower saturation 40 %). It was established that the reserves of available moisture for the period of winter wheat sowing were the highest in the grain-row specialized crop rotation, where wheat was sown after buckwheat with 257,2 mm in the 0–150 cm layer, 78,5 mm in the 0–50 cm layer. In the crop rotation in the 0–150 cm layer, they were 204,3 mm, in the 0–50 cm and 50–100 cm layers 59,4 and 52.4 mm, which is 19,1 and 15.0 less than in the grain-row crop rotation mm. During the crop rotation, the reserves of available moisture for the harvesting period were 1372 m3/ha, grain-rowing – 1154 m3/ha, specialized grain-rowing and row-rowing – 1327 and 928 m3/ha, which affected the total moisture consumption. The highest consumption of available moisture was observed during row crop rotation - 4029 m3/ha, while during crop rotation the available moisture reserves were 4032 m3/ha. The coefficient of moisture consumption was the highest in specialized and row-row crops – 97,8 and 90,7 m3/t, respectively, while for crop rotation – 70,7, grain-row crops – 85,2 m3, which was less than row crops by 5,5 and 20 m3/t.

The effect of sowing dates and seed rates on field germination of new varieties of wheat

The article presents the effect of sowing dates and seed rates on the field gemination of seeds of new varieties of durum wheat Javahir, Mingchinor, Langar, Yoqut-2014 in drought conditions. The complete harvest of winter durum wheat and its wintering, storage until harvest, and ultimately, obtaining an abundant and high-quality grain harvest from the crop directly depend on the correct determination of the optimal sowing period and norms. The purpose of the study was to determine the effect of sowing dates and seed rates on the field germination of new durum wheat in the conditions of typical gray soils of the drought conditions of Kashkadarya region. In research, the highest germination of durum wheat seeds was observed when planted on October 21, that is, the fertility of seeds compared to when planted on October 1 (control) was 2.9 in accordance with Javokhir, Mingchinor, Langar, Yoqut-2014 varieties; 2.7; 3.2; increased by 3.3%. A decrease in field fertility of all durum wheat cultivars was observed with late sowing. This indicator is 5.8 in the Jawakhir variety compared to the one planted on October 21 in the first ten days of December; 6.1 in Mingchinor; 6.3 at anchor; Ruby decreased by 6.4% in 2014. In the Mingchinor variety, 2.1% delay in planting dates from October 21 and 6.6% decrease in seed germination in field conditions were found. In the article, the impact of planting dates and standards of durum wheat varieties Javahir, Mingchinor, Langar, Yoqut-2014 included in the State Register of Agricultural Crops on field germination was studied and recommendations were given based on the experimental results.

Analysis of a pneumatic seeder equipped with an improved planting disc

The article analyzes the results of field experiments of a pneumatic seeder that accurately plants a bare cotton seed equipped with an improved planting disc. The type and parameters of a pneumatic seeding machine that precisely slots and plants bare seeds suitable for the harsh soil and climatic conditions existing in the world have been studied through field trials to ensure that an economic effect can be achieved with adequate research. The experiments were carried out during the spring sowing period. In addition, the parameters of an improved pneumatic seeder drive that accurately shows bare cotton seed have been scientifically substantiated. The article presents conclusions based on the results obtained.

Determination of planting periods of early, middle and late varieties of melon

This article meticulously explores the critical aspects of agricultural timing and plant development by examining the optimal sowing periods, germination rates, flowering phases, and the ripening process of various fruit cultivars. Focusing specifically on early-ripening varieties such as “Tarnak,” “Khandalak,” and “Gurvak,” alongside middle-ripening types like “Zargulobi,” “Ak Novvot,” and “Qariqiz,” and concluding with late-ripening varieties such as “Amudarya,” “Sakovat,” and “Gulobi Khorezmi,” the study investigates the distinct climatic and soil conditions of the Khorezm region. Through systematic experimentation and data analysis, the research identifies optimal sowing times that correspond to each variety’s growth cycle, thereby enhancing overall productivity. The findings indicate that the selected varieties demonstrate significant yield potential when aligned with the best agronomic practices. Ultimately, this study serves as a valuable resource for local farmers and agricultural experts, providing insights that can lead to informed decision-making and increased fruit production in the region. By emphasizing the importance of timing in cultivation, this research contributes to the broader discourse on sustainable agriculture and food security.

ЭЛЕМЕНТЫ ТЕХНОЛОГИИ ВОЗДЕЛЫВАНИЯ СОИ В РСО-АЛАНИЯ

The author presents the results of research on the study of sowing dates for soybean yields in the conditions of the forest-steppe zone of the Republic of North Ossetia-Alania. With the introduction of new varieties of various ripeness in the main and intermediate crops, there is a need to improve the timing of sowing. The purpose of the work is to study the effect of sowing dates on the yield of soybean seeds in the conditions of the foothill zone of the Russian Federation. The scientific novelty was to establish optimal sowing dates that would ensure optimal plant growth and development and high productivity. Our research was carried out in the experimental fields of the North Caucasus Scientific Research Institute of Mountain and Foothill Agriculture of the VNC RAS in 2018-2021. The object of research was the varieties of breeding of the Federal Scientific Center of the V.S. Pustovoit Research Institute of Oilseeds. Two main types of soils prevail in the foothill zone: chernozems of varying degrees of leaching, as well as meadow and meadow-marsh soils. The arable layer contains from 3 to 4.4% humus. Down the profile, the amount of humus decreases gradually. The reaction of the soil solution in the upper horizons is neutral, deeper than 80-90 cm – slightly alkaline. The predecessor of the experimental plots was corn for grain. It was found that at early sowing dates (April 20 – May 5), higher field germination (87-93%), plant foliage of 46.9 thousand m2/ha and their survival rate for harvesting 84-91% were noted. More nodules formed on the roots of the plants. The maximum yield is 2.6 t/ha, obtained during sowing on April 30. In the forest-steppe zone, the yield of medium-ripened varieties decreased from early to late sowing periods by 0.44 and 0.58 t/ha, while in early-ripening varieties it was less significant. Fertilizers (R90K30) increased the yield of seeds, depending on the timing of sowing, by 0.24-0.58 t/ha.

Large-Scale Freezing and Thawing Model Experiment and Analysis of Water–Heat Coupling Processes in Agricultural Soils in Cold Regions

Heilongjiang Province, the largest commercial grain base in China, experiences significant challenges due to the environmental effects on its soil. The freezing and thawing cycle in this region leads to the transport of water and heat, as well as the exchange and transfer of energy. Consequently, this exacerbates the flooding disaster in spring and severely hampers farming activities such as plowing and sowing. To gain a better understanding of the freezing and thawing mechanisms of farmland soil in cold regions and prevent spring flooding disasters, this study focuses on Heilongjiang Province as a representative area in northeast China. The research specifically investigates the frozen and thawed soil of farmland, using a large-scale low-temperature laboratory to simulate both artificial and natural climate conditions in the cold zone. By employing the similarity principle of geotechnical model testing, the study aims to efficiently simulate the engineering prototypes and replicate the process of large-span and long-time low temperatures. The investigation primarily focuses on the evolution laws of key parameters, such as the temperature field and moisture field of farmland soil during the freeze–thaw cycle. The findings demonstrate that the cooling process of soil can be categorized into three stages: rapid cooling, slow cooling, and freezing stabilization. As the soil depth increases, the variability of the soil temperature gradually diminishes. During the melting stage, the soil’s water content exhibits a gradual increase as the temperature rises. The range of water content variation during thawing at depths of 30 cm, 40 cm, 50 cm, and 80 cm is 0.12% to 0.52%, 0.47% to 1.08%, 0.46% to 1.96%, and 0.8% to 3.23%, respectively. To analyze the hydrothermal coupling process of farmland soil during the freeze–thaw cycle, a theoretical model of hydrothermal coupling was developed based on principles of mass conservation, energy conservation, Darcy’s law of unsaturated soil water flow, and heat conduction theory. Mathematical transformations were applied after defining the relative degree of saturation and solid–liquid ratio as field functions with respect to the relative degree of saturation and temperature. The simulated temperature and moisture fields align well with the measured data, indicating that the water–heat coupling model established in this study holds significant theoretical and practical value for accurately predicting soil temperature and moisture content during the spring sowing period, as well as for efficiently and effectively utilizing frozen soil resources in cold regions.