Optimum Sowing Date Research Articles

Influence of climatic variables on maize grain yield and its components by adjusting the sowing date.

Yield and its components are greatly affected by climate change. Adjusting the sowing date is an effective way to alleviate adverse effects and adapt to climate change. Aiming to determine the optimal sowing date of summer maize and clarify the contribution of climatic variables to grain yield and its components, a consecutive 4-year field experiment was conducted from 2016 to 2019 with four sowing dates at 10-day intervals from 5 June to 5 July. Analysis of historical meteorological data showed that more solar radiation (SR) was distributed from early June to mid-August, and the maximum temperature (Tmax) > 32°C appeared from early July to late August, which advanced and lasted longer in 1991-2020 relative to 1981-1990. Additionally, the precipitation was mainly distributed from early June to late July. The climate change in the growing season of summer maize resulted in optimal sowing dates ranging from 5 June to 15 June, with higher yields and yield stability, mainly because of the higher kernel number per ear and 1,000-grain weight. The average contribution of kernel number per ear to grain yield was 58.7%, higher than that of 1,000-grain weight (41.3%). Variance partitioning analysis showed that SR in 15 days pre-silking to 15 days post-silking (SS) and silking to harvest (SH) stages significantly contributed to grain yield by 63.1% and 86.4%. The extreme growing degree days (EDD) > 32°C, SR, precipitation, and diurnal temperature range (DTR) contributed 20.6%, 22.9%, 14.5%, and 42.0% to kernel number per ear in the SS stage, respectively. Therefore, we concluded that the early sowing dates could gain high yield and yield stability due to the higher SR in the growing season. Meanwhile, due to the decreasing trend in SR and increasing Tmax trend in this region, in the future, new maize varieties with high-temperature resistance, high light efficiency, shade tolerance, and medium-season traits need to be bred to adapt to climate change and increased grain yield.

Genetic analyses of grain yield and yield-attributing traits in wheat (Triticum aestivum L.) grown under terminal heat stress

Abstract (286) Terminal heat stress is a key constraint in wheat cultivation and its impact is anticipated to increase in the current context of climate change. Heat stress poses a serious threat, especially during the reproductive and grain-filling stages in wheat that can causes a significant reduction in yield. The current research was carried out to assess the nature of genetic variability and the relationship between yield and yield attributing traits of 30 different wheat genotypes grown under terminal heat stress and also to isolate the best performing genotypes based on stress tolerance indices. The highest estimates of PCV and GCV were observed for plant height (67 and 65, respectively). Most of the traits showed high heritability, among which days to germination (98.45%), plant height (96.51%), total grain per plant (99.71%) exhibited the highest. The highest genetic advance was estimated in filled spikelet per spike (97.37%). Total grain weight and hundred grain weight had strong positive correlation with yield per plant. The characters viz., plant height, chlorophyll content, no. of tiller per plant, days to 50% flowering, filled grain, hundred grain weight, flag leaf length, days to booting, total grain weight had a positive direct effect on grain yield. In this experiment, SADH-2, DSN-76, NK-5, NE-3, SA-2 had the lowest value of TOL which indicated that they had high tolerance towards heat stress. The highest value of YSI was observed in DSN-76, NE-3, BAW 1008, NK-5, SADH-22 which indicated that they had lower yield reduction and higher yield stability under heat stress. The optimum sowing date showed better performance for all the examined traits compare to heat stress condition. The identified genotypes hold promise for future breeding programs aimed at developing wheat varieties resilient to terminal heat stress.

Effect of Dates of Sowing and Nutrient Levels on Yield and Yield Attributes of Sunn hemp (Crotalaria juncea)

A field trial was done to determine the optimum sowing date and nutrient levels on yield and yield parameters of Sunn hemp during summer (January - May) 2022 at Eastern Block Farm, Tamil Nadu Agricultural University, Coimbatore. The field trial was laid out with 12 treatments in a split-plot design and every treatment was replicated thrice. Three sowing dates (the last week of January, the first and second weeks of February) were performed in the main plot, and four different nutrient levels (20:40:20 kg NPK ha-1, 25:50:25 kg NPK ha-1, 30:60:30 kg NPK ha-1 and 12.5 tons FYM ha-1) in the subplot. Yield attributes such as the number of pods per plant, Seeds per pod, seed index, pod setting percentile, pod filling percentile, and seed yield were noted. Sunn hemp sown during the second week of February along with 30:60:30 kg NPK ha-1 was noted with higher yield attributes and seed yield of Sunn hemp

Soybean yield dependence on the timing of sowing in the conditions of the foothill zone of the RNO-Alania

The article presents the results of research on the reaction of soybean plants depending on the timing of sowing in the foothill zone of the Republic of North Ossetia-Alania. The need to improve the timing of sowing occurs with the introduction of new varieties of various ripeness in the main and intermediate crops. The purpose of the paper is to study the effect of sowing dates on the yield of soybean seeds in the conditions of the foothill zone of the RNO-Alania. 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 Caucasian Research Institute of Mountain and Piedmont Agriculture of the VSC RAS in 2018-2021. The object of research was the varieties of breeding of the Federal scientific center "V.S. Pustovoit All-Russian Research Institute of Oil Crops. Two main types of soils prevail in the foothill zone: chernozems of varying degrees of leaching, as well as meadow and meadow-boggy 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, in horizons 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) resulted in higher field germination (87-93%), plant foliage of 46.9 thousand m2/ha and their survival rate for harvesting 84-91%. More nodules formed on the roots of the plants. The maximum yield is 2.6 t/ha, obtained during sowing on April 30.

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.

The Effect of Sowing Date on the Growth and Yield of Soybeans Cultivated in North-Eastern Poland

Soybean yields are influenced by numerous factors, including environmental conditions, location, and agricultural practices. Sowing date affects plant growth, development, and yields, and it plays a particularly important role in soybean cultivation. The optimal sowing date should be selected based on soil temperature, precipitation, and rainfall distribution in a given region. The aim of this study was to determine the effect of various sowing dates (I—early, II—optimal, III—late) on the time from sowing to emergence of soybean seedlings, length of the growing season, morphological traits of soybean plants, yield components, and seed yields of soybeans grown in north-eastern Poland. Sowing date considerably affected the time from sowing to the emergence of soybean seedlings and seed yields. In north-eastern Poland, soybeans should be sown in the first half of May to minimize the risk of ground frost damage, which can occur even in late May. Sowing date also influenced soybean yields. In north-eastern Poland (Region of Warmia and Mazury), yields were maximized when soybeans were sown late (in mid-May), which was decisively influenced by climatic conditions, mainly temperature. The linear regression analysis revealed that the length of the growing season was correlated with the seed yields of soybeans sown on different dates.

Creation of a green forage chain and haylage making from annual feed crops in Yakutia

The main branch of agriculture in Yakutia is animal husbandry. One of the urgent problems is the provision of livestock with feed. The basis for increasing the productivity of dairy cattle breeding is succulent and green feed. The main raw material for succulent and vitamin feed in Yakutia is the green mass of annual feed crops. The purpose of the research was to consider the creation of a green forage chain and the production of haylage from annual feed crops in Yakutia. The results of research on the creation of a green forage chain and the production of haylage from annual feed crops have been presented in the article. The research was carried out on the basis of the feed production laboratory of the Yakut Scientific and Research Institute of Agriculture in 2019–2021. Data on the yield, nutritional value of annual feed crops for the production of haylage and the creation of the green forage chain have been given. In order to obtain nutritionally balanced feed, the optimal species composition of mixed crops for the green forage chain and haylage was determined, optimal sowing dates and the mode of use of annual crops were established. On permafrost meadow-chernozem soils for the production of haylage, it is recommended to cultivate a vetch-oat mixture with a seeding rate of components: vetch 1,2 million pcs./ha + oats 2,5 million pcs./ha, pea-oat mixture with a seeding rate of components: peas 0,8 million pcs./ha and oats 2,5 million pcs./ha of germinating seeds. On the green forage chain, we recommend the vetch-oat mixture (vetch 1,2 million pcs./ha + oats 2,5 million pcs./ha), rapeseed-oat (rapeseed 2,0 million pcs./ha + oats 1,5 million pcs./ha). Obtaining raw materials for the production of haylage from annual feed crops gave an economic effect for 1 rub. of costs 1,42–1,53 rub. of income, and for creating the green forage chain for 1 rub. of costs gave 1,19–1,50 rub. of income, depending on the timing of sowing.

Determination of optimum sowing date for higher productivity and profitability in sesamum (Sesamum Indicum L)

Determination of optimum sowing date for higher productivity and profitability in sesamum (Sesamum Indicum L)

Association of cropping practices, cropping areas, and foliar diseases of common bean (Phaseolus vulgaris L.) in Ethiopia

Common bean production is being constrained by a number of diseases. The survey was carried out to prioritize common bean diseases and their associations with cropping areas and cultural practices. A stratified random assessment on 114 farmer's fields was conducted in Ethiopia's four common bean producing zones (Metekel, Sidama, Wolaita, and Halaba). Data are collected randomly on disease severity, incidence levels, and agronomic practices. The results revealed that eleven foliar diseases were found to affect common bean production. Among them, the maximum disease severity and distribution was scored for angular leaf spot (Pseudocercospora griseola) (mean disease severity of 17.8%) and bean anthracnose (Colletotrichum lindemuthianum) (10.9%) followed by floury leaf spot (Mycovellosiella phaseoli), ascochyta blight (Ascochyta phaseolorum Sacc), and web blight (Thanatephorus cucumeris). A multiple correspondence analysis was conducted, and revealed a significant association between the diseases, cropping areas and cultural practices. Optimal crop density was found to be associated with lower bean anthracnose and mosaic virus severities, while being liked to high levels of angular leaf spot and frog-eye leaf spot. Additionally, optimum sowing dates were associated with low severities of bean anthracnose, angular leaf spot, frog-eye leaf spot, Halo Blight, and mosaic virus. On the other hand, a high weediness level was found to be associated with higher levels of web blight and bean anthracnose. Intercropping and row planting were obtained to reduce angular leaf spot and increase occurance of ascochyta blight compared to monocropping. Furthermore, row planting were found to decrease bean anthracnose, angular leaf spot, and cercospora leaf spot when compared to broadcasting. The application of fertilizer was found to decrease the occurances of bean anthracnose, halo blight, floury leaf spot, and angular leaf spot. Therefore, efforts should focus on the optimization and integration of cultural practices for managing disease and producing common bean sustainably.

Жизнеспособность семян и адаптивность раннеспелых гибридов кукурузы в условиях Южного Урала

Abstract. The purpose is to study and identify the best high-yielding with rapid loss of grain moisture during ripening, ecologically plastic and stable corn hybrids adapted to the conditions of the Southern Urals. Methods. The studies were carried out in 2017–2020 in the North Caucasian and Ural regions of the Russian Federation at the earliest and optimal sowing dates, taking into account the temperature regime of the soil. Eight new early-ripening maize hybrids of the FSBSI ARRSI of corn breeding in 2016 were studied. Laboratory seed germination was determined at a temperature of +20 °C according to the method of V. S. Sotchenko and others and by cold germination in filter paper rolls after each year of storage. Field germination was determined by counting the number of seedlings after sowing. Plasticity and stability were calculated according to the method of S. F. Eberhart, W. F. Russel. Results. After four years storage of corn hybrids Nur and Mashuk 170 MV, the laboratory germination of seeds remained at the level of 98–99 % with cold germination. In the conditions of the Ural region, the hybrids Baikal and Mashuk 171 became ecologically plastic and productive, referring to high intensity forms. The hybrids with the lowest grainharvesting moisture for all the years of studying Bilyar 160 (27.0 %) and Ural’skiy 150 (27.5 %) were identified as adapted for growing for grain in the Ural region. Scientific novelty. For the first time, a variety test of new early-ripening maize hybrids bred by FSBSI ARRSI of corn was carried out in two ecological and geographical points. The results of the study of ecological plasticity, adaptability to natural and climatic conditions, yield, harvest moisture content of grain, preservation of the viability of seeds of hybrids during storage will make it possible to identify the most adaptive early-ripening hybrids according to a set of characteristics for the conditions of the Ural region.

Effect of Weather Indices under Different Sowing Windows on Grain Yield of Sorghum

Background: Sorghum (Sorghum bicolor L. Moench) is one of the major staple cereal crops after rice and wheat. Photoperiod (day length) sensitivity has been shown to affect the duration of plant’s vegetative phase based on sowing dates. Optimum sowing date is one of the most important factors that play an important part in yield. Methods: A field experiment was carried out during the summer season of 2022. in the Eastern block farm (37F) of Tamil Nadu Agricultural University, Coimbatore in sandy loam soil to study the phenological behaviour of sorghum as influenced by sowing window (D1 - First fortnight of February, D2 - First fortnight of march and D3 - First fortnight of April) by analysing the Helio-thermal units (HTU), Photo-thermal units (PTU) and growing degree days (GDD) and to evaluate the performance of sorghum CO-32 cultivar. The experiment was laid out in strip plot design. Results: Among the different sowing windows highest grain yield was recorded when sowing was done in I FN of April (2602.81 kg/ha) followed by I FN of March (2484.53kg/ha). The attainment of phenophases was found early in February sowing. It was observed that accumulated heat units increased by 114 °C and 142.2 °C days in March and April sown crop compared to February sown crop. Among the sowing windows maximum photo thermal units were accumulated by April sown crop (15135.2oC day hrs) followed by March (13485.57oC day hrs) and February (11608.5oC day hrs) sown crop respectively.

Exploring DSSAT Model Genetic Coefficient Estimation Methodologies for Chickpea in Bundelkhand Region of Uttar Pradesh, India

In modern crop production, essential factors that contribute to narrowing yield gaps and minimizing production costs include making informed decisions about the selection of plant varieties, determining optimal sowing dates, determining appropriate plant populations, selecting suitable fertilizer rates, and implementing effective pest control methods. Two field experiments were conducted during the Rabi seasons of 2021 and 2022 at ICAR-Indian Institute of Pulses Research (IIPR), Kanpur using split-plot experimental design, where the main plots were three different sowing dates (20-25th October, November 10-15th, and 25th November-5th December), and the sub-plots were four chickpea cultivars (JG 16, RVG 202, IPC-07-66, and IPC-05-62), each with three replications. The genetic coefficients of the cultivars were estimated using both the iterative process (IP) and Generalized Likelihood Uncertainty Estimation (GLUE) methods in DSSAT v 4.7 to simulate the yields. Upon model validation, it was found that the average relative error (ARE) in predicting grain yield across the different sowing windows was between -25.7% to 29.1% when using the iterative process, while ARE was between -23.4% to 19% when using GLUE. The findings report more accurate simulations of chickpea growth and phenological development stages were recorded in normal sowings. And the model calibration suggest that GLUE provided superior estimates of genetic coefficients compared to the IP method. Therefore, it can be inferred that Glue is a more user-friendly and precise method.

Optimizing sowing date and plant density improve peanut yield by mitigating heat and chilling stress

AbstractPeanut (Arachis hypogea L.) yield is dramatically declined by extreme weather stresses under climate change. Adjusting the sowing date and plant density are effective strategies to mitigate these stresses and improve peanut yield. However, a mechanistic understanding of the influence of environmental drivers and an optimized strategy have yet to be developed. Here, a 3‐year field experiment was conducted to evaluate the sowing date (April 25, early sowing; May 5, middle sowing; May 15, late sowing) and plant density (24, 30, and 36 plants m−2 as low, medium, and high) of peanut in the North China Plain. We found that higher pod yield was observed in the middle sowing (∼4492.4 kg ha−1) compared with the early and late sowing (∼3317.2 and 4088.1 kg ha−1, respectively). Meanwhile, the pod yield in high density (∼4162.5 kg ha−1) was 10.6% and 4.7% higher than low and medium density, respectively, mainly due to higher leaf area index. The relative peanut pod yield was positively correlated with the average minimum temperature 5 days before and after the flowering pegging stage, whilst it was negatively correlated with average maximum temperature 5 days before and after pod filling stage. Therefore, optimizing temperature conditions to improve the peanut yield can be achieved by adjusting the sowing date. In conclusion, sowing date and plant density manipulation constitute a useful method to mitigate heat and chilling stress and improve peanut yield.

Adaptability of wheat to future climate change: Effects of sowing date and sowing rate on wheat yield in three wheat production regions in the North China Plain

Adjusting sowing dates and sowing rates is a key adaptation strategy for adapting to future climate change, and maintaining wheat production in the North China Plain (NCP). However, it is still unclear whether the current sowing date and sowing rate can adapt to future climate change, and how to adjust the sowing date and sowing rate to compensate for the adverse effects of climate change on wheat yields. This study predicts the adaptability of agricultural management practices like sowing dates and sowing rates, to future climate change in three wheat regions by referring to four global climate models (GCMs) and AquaCrop model. Population structure and yield were maximized for sowing dates from Oct.11–20 and sowing rates of 10–13 kg/667 m2 (or 13–16 kg/667 m2) in 2016–2021. Three wheat regions were expected to show a warming trend, while the total precipitation has large spatial fluctuations under both representative concentration pathways (rcp) scenarios in the 2022–2100. AquaCrop model could simulate yield with a good precision (RMSE≤1043.7 kg/ha). Compared to the average yield of the baseline period (2016–2021), in the 2022–2100, the average predicted wheat yields of three wheat regions simulated based on the current optimal sowing date and sowing rate decreased by 5.45 % ∼ 11.05 % (9.35 % ∼ 16.84 %) and 2.57 % ∼ 10.95 % (6.97 % ∼ 12.75 %) under the rcp4.5 (rcp8.5), respectively. Average wheat yield losses were effectively compensated when the combinations of Oct.15 and 14 kg/667 m2 for the dryland wheat, Oct.21 and 14 kg/667 m2 for the irrigated wheat, and Oct.21 and 13 kg/667 m2 for the high-yield-rainfed wheat were applied under both rcp scenarios, respectively, with predicted yield losses of −4.17 %, −3.50 %, and − 3.25 %. Thus, adjusting sowing dates and sowing rates are viable options to effectively address the adverse effects of future global climate change, thereby guaranteeing food security in the NCP.

Predicting rice phenology and optimal sowing dates in temperate regions using machine learning

AbstractCrop phenology modeling often involves determining variety‐specific growing degree day thresholds, or parameterizing mechanistic crop models. In this work, we used machine learning methods to develop models that provide daily predictions of the probability that rice (Oryza sativa) crops had reached the panicle initiation and flowering growth stages. These per‐date classifications were summarized into per‐paddock growth stage transition dates, which were then compared with field‐sampled reference data, encompassing 15 rice varieties, 10 years, and 380 sites. Leave‐one‐year‐out cross validation was used to provide realistic estimates of model errors. Compared with more complex and computationally intensive algorithms, logistic regression produced competitive results (mean cross‐season validation RMSE 3.9 and 5.2 days for panicle initiation and flowering, respectively). Logistic regression had additional advantages: providing confidence of growth stage predictions at each date (as it is a probabilistic algorithm), and straightforward explainability (as model parameters directly indicated how the various input variables contributed to growth stage predictions). Input variables included accumulated weather, rice variety, and sowing methods. The models were applied to forecasting phenology transition dates of the rice crops planted throughout the Murray and Murrumbidgee valleys. In addition, recommendations for optimal sowing dates were developed, using simulations involving more than 40 years of weather data, with the goal of minimizing the risk of cold‐temperatures during the microspore growth phase, which can severely degrade yield in temperate rice growing regions.

Determination of optimum planting time of different Sesame (Sesamum indicium L.) varieties for Chewaka district, Western Oromia, Ethiopia

Sowing date is the major problem in the production and productivity of sesame in western Oromia Ethiopia. The experiment was conducted to identify optimum sowing dates for sesame varieties to produce better seed yields. A field experiment consisting of the combination of three sesame varieties and three sowing times employed Randomized Complete Block in factorial arrangements with three replications. Analysis of variance indicated that plant height; branches number per plant and number of capsules per plant were significantly increased with sowing sesame at the onset of rainfall. All sesame varieties sown on the onset of rainfall gave the maximum seed yield in both years whereas three varieties had low yield at 10 days after the first and 20 days after the first. Among the three varieties, the Walin variety produced a maximum seed yield of 670 and 747 kg ha-1 on a farm in the first and second year respectively. The maximum yield (670 and 971 kg ha-1) was obtained from Walin and Obsa sesame varieties in the first and second years of the farm respectively. Therefore, the result indicated that sowing sesame varieties at the onset of rainfall is recommended for Chewaka areas and similar agroecology.

Seed priming influences on yield and protein content of wheat sown at different time

The aim of this field experiment conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, was to investigate the impact of different seed priming techniques and sowing dates on the yield and quality of wheat. The study aimed to identify the most effective seed priming technique and optimal sowing date to enhance wheat productivity and minimize yield reduction. The experiment employed a split plot design with two factors: seed priming techniques (no priming, hydropriming with distilled water, osmopriming with PEG, and halopriming with CaCl2) and sowing dates (November 20, December 05, and December 20). The trial was conducted from November 2019 to April 2020 at the research field. The study consisted of three replications for each treatment combination. Osmopriming exhibited the most favorable results among all priming techniques, showing significantly higher values for effective tillers hill-1 (3.91), number of grains spike-1 (43.82), number of spikelets spike-1 (16.16), grain yield (3.87 tons hectare-1), biological yield (6.02 t ha-1), and harvest index (39.03%). No priming condition resulted in the highest protein content (12.11%), while osmopriming had the lowest protein content (11.77%). The sowing conducted on November 20 yielded the highest number of effective tillers hill-1 (3.57), number of grains spike-1 (42.49), number of spikelets spike-1 (15.75), grain yield (3.71 t ha-1), biological yield (9.70 t ha-1), and lowest protein content (11.74%). Sowing on December 20 resulted in the highest protein content (12.20%). Based on the study's findings, it can be concluded that the osmopriming technique, combined with sowing on November 20, offers the most promising approach to mitigate the yield reduction of wheat. This combination demonstrated the highest grain yield (4.23 t ha-1) compared to other treatments. Therefore, farmers and agricultural practitioners are recommended to adopt the osmopriming technique with a sowing date of November 20 for optimizing wheat production and enhancing overall crop quality.

Урожайность озимой пшеницы в зависимости от сроков и норм высева

Abstract. The article presents the results of experimental studies on the study of seeding rates – 3, 4, 5 million germinating seeds per 1 ha, and sowing dates, in the rainfed conditions of the steppe zone of the Republic of North Ossetia Alania, on two new high-yielding varieties – Gomer and Bagrat, bred by the National Central Plant named after. P. P. Lukyanenko. The purpose of the research is to study the optimal sowing dates and sowing rates of new high-yielding winter wheat varieties in the conditions of the steppe zone of North Ossetia-Alania. Scientific novelty. For the first time in specific soil and climatic conditions of the steppe zone, the reaction of new zoned varieties to different sowing dates and seeding rates was studied. Methodology. The studies were carried out in 2019–2021, on the experimental fields of the Vladikavkaz Scientific Center, located in the steppe zone of the Mozdok region. Sowing was carried out on September 10, 20, 30. We studied seeding rates of 3, 4, and 5 million germinating seeds. Before sowing, the seeds were treated with “Tabu Neo” insecticide (to protect seeds from pests) and “Maksim Forte” fungicide (to protect seeds from pathogens). Results. It has been established that the sowing of winter wheat in the third sowing period (September 30) with a seeding rate of 5 million. of germinating seeds per 1 ha showed the best results in terms of yield, where the yield of the Gomer variety was – 4.74 t/ha, when the same variety, when sown in the 1st term (September 10), the yield was 4.45 t/ha. The same trend was revealed for the variety Bagrat, where the yield was the highest – 4.65 t/ha, with a seeding rate of 5 million seedlings. Seeds per 1 ha in the third sowing period. The studied varieties formed a heavier grain in the third sowing period (September 30). In the winter wheat variety Homer, the weight of 1000 seeds was 45.4 g. in the variety Bagrat – 43.9 g.

Effect of Sowing Date on the Growth Characteristics and Yield of Growth-Constrained Direct-Seeding Rice.

To investigate changes in the yield and physiological characteristics of indica hybrid rice varieties sown on different dates, we evaluated appropriate hybrid rice varieties and their optimal sowing dates in the hilly areas of Sichuan. Three popular indica rice varieties were used as experimental materials, and five sowing dates were set uniformly locally [16 May (SD1), 23 May (SD2), 30 May (SD3), 6 June (SD4), and 13 June (SD5)] to investigate differences in the yield characteristics, growth period, and dry matter accumulation. The results showed that, over the two years, the sowing-to-heading period and overall growth period of the three varieties shortened as the sowing date was delayed, and the difference in yield between the SD1 and SD2 treatments was not significant, owing to higher material accumulation after flowering and higher assimilative material transport capacity. These varieties are both photosensitive and tolerant to low temperatures. Among the three varieties tested, the Huangyouyuehesimiao (V3) cultivar had the highest yield, with 10.75 t ha-1 under the SD2 treatment. The impact of shifting the sowing date on yield components varied. Delaying the sowing date increased and then decreased the number of effective panicles, and the number of grains per panicle and the seed setting rate decreased by differing degrees. In summary, a high yield of indica hybrid rice can be maintained by sowing between 16 and 23 May each year in the study area. It indicated that indica hybrid rice in the hilly rice-producing region of Sichuan is highly adaptable to different sowing dates.

Yield and Yield Components of Winter Poppy (Papaver somniferum L.) Are Affected by Sowing Date and Sowing Rate under Pannonian Climate Conditions

Poppy cultivation has a long tradition in Central Europe. Growing winter poppy instead of the commonly grown spring poppy might increase seed yield, especially in the face of changing climatic conditions. However, knowledge regarding optimum sowing date and optimum sowing rate for winter poppy under Pannonian climate conditions in Central Europe is missing. Therefore, a two-year field experiment was performed in Eastern Austria with four sowing dates ranging from early September to mid/end of October and two sowing rates with 50 or 100 mg seeds m−2. Seed yields were considerably higher than values reported for spring poppy throughout all sowing dates, mainly due to a higher number of seeds capsule−1 and, thereby, a higher seed yield capsule−1. The highest seed yields were obtained by sowing in early October, while the earliest and especially the latest sowing date resulted in lower seed yields. Consequently, the optimum sowing date for winter poppy under Pannonian climate conditions in Central Europe is early October but sowing can be performed over a wider range of dates. No seed yield differences were observed between sowing rates. Consequently, the sowing rate can be much lower than the recommended sowing rate for spring poppy.