Suitable Sowing Research Articles

Comparison of population photosynthesis characteristics and grain yield of wheat under various sowing dates and seeding rates

AbstractThis study investigated the effects of sowing dates and seeding rates on photosynthetic characteristics and grain yield in wheat (Triticum aestivum L.). A field experiment was conducted with three sowing dates—early sowing date (SD‐E), normal sowing date (SD‐N), and delay sowing date (SD‐D)—and three seeding rates—90 low seeding rate (SR‐L), 108 moderate seeding rate (SR‐M), and high seeding rate 126 kg ha−1 (SR‐H). The results revealed that the grain yield at SR‐L in the SD‐E regime, SR‐M in the SD‐N regime, and SR‐H in the SD‐D regime was increased by 7.48%–9.93%, 14.1%–16.7%, and 19.0%–41.6%, respectively, compared to other combinations under the same sowing date. Consistent with the yield performance, the aboveground biomass accumulation, nonstructural carbohydrates (NSC) accumulation in stems, and NSC remobilization amount from anthesis to maturity were the highest at SR‐L in the SD‐E, at SR‐M in the SD‐N, or at SR‐H in the SD‐D regime, among other treatment combinations. Improved canopy photosynthetic characteristics (i.e., leaf area index, leaf photosynthetic rate, canopy photosynthetically active radiation interception rate, and radiation use efficiency) were also observed at the SR‐M in the SD‐N or at SR‐H in the SD‐D regime. Collectively, a suitable sowing date combined with an optimum seeding rate could enhance grain yield, and increasing the seeding rate could mitigate the yield loss when sowing was delayed by optimizing traits photosynthesis in wheat.

Structural and physicochemical effects on the starch quality of the high-quality wheat genotype caused by delayed sowing.

Bread wheat is one of the most important food crops associated with ensuring food security and human nutritional health. The starch quality is an important index of high-quality wheat. It is affected by a complex series of factors; among which, suitable sowing time is a key factor. To analyze the integrative effects of sowing time on the starch quality of high-quality wheat, in the present study, we selected a high-quality bread wheat cultivar Jinan 17 and investigated the effect of different sowing times on the starch properties and the related genes by analyzing X-ray diffraction patterns, apparent amylose content, thermal properties, pasting properties, in vitro starch digestibility, and qRT-PCR. Meanwhile, we also investigated the agronomic and yield performance that may be associated with the starch properties. Delayed sowing had little effect on starch crystalline morphology, but there was a tendency to reduce the formation of crystals within wheat starch granules: (1) delayed sowing for 15 days altered the thermal properties of starch, including onset, peak and termination temperatures, and enthalpy changes; (2) delayed sowing for 30 days changed the thermal characteristics of starch relatively insignificant; (3) significant differences in pasting characteristics occurred: peak viscosity and hold-through viscosity increased, while final viscosity, breakdown viscosity, and setback viscosity tended to increase and then decrease, suggesting that delayed sowing caused changes in the surface of the starch granules resulting in a decrease in digestibility. Analysis of related genes showed that several key enzymes in starch biosynthesis were significantly affected by delayed sowing, leading to a reduction in apparent straight-chain starch content. In addition to starch properties, thousand-kernel weight also increased under delayed sowing conditions compared with normal sowing. The impact of delayed sowing on starch quality is multifaceted and complex, from the fine structure, and functional properties of the starch to the regulation of key gene expression. Our study holds significant practical value for optimizing wheat planting management and maximizing the potential in both quality and yield.

Climate-smart cotton (Gossypium herbaceum) crop production in Punjab: A comprehensive review of sustainable management practices

The growth and productivity of cotton (Gossypium herbaceum L.) crop are greatly influenced by major fluctuations in the local weather. The output of cotton is negatively impacted by extended periods of unfavourable weather, despite the crop's apparent relative resistance to heat and drought. Among various cotton growing states in India, Gujarat often leads as the highest cotton-producing state in the country followed by Maharashtra, Telangana, Rajasthan, Karnataka and Andhra Pradesh. These states collectively contribute more than 65% to India's cotton production. In Punjab, the optimal sowing window for cotton spans from the 1stApril to 15th May. Deviating from this recommended time frame, be it through excessively early or late sowing, correlates with compromised crop establishment and reduced productivity. Temperature thresholds dictate progression of the cotton crop's key stages. For germination, a threshold temperature of 16°C is required, while the range of 21 to 27°C is conducive to vegetative growth, and 27 to 32°C supports reproductive development. The diurnal/night time temperature for fostering cotton root growth resides within 30°C/22°C to 35°C/27°C. Elevated temperatures (40°C/32°C), even under adequate water and nutrient conditions, results in the emergence of shallow root systems. Strategic measures encompassing suitable sowing dates, precise plant spacing, favourable row orientations, judicious irrigation techniques and mulching can effectively temper the influence of climate change on cotton output. Furthermore, the application of crop simulation models and access to timely, accurate weather forecasts and agro-advisories equips decision-makers with invaluable insights for short-term operational planning.

Yield and Quality Traits of Black Cumin (Nigella sativa L.) Genotypes in Response to the Different Sowing Dates

Black cumin has been used in many countries for the treatment of diseases such as cancer and diabetes, and for thousands of years as a spice, flavoring in products such as bread, and as a food preservative in pickles. Too much delay in the sowing of black cumin has a negative effect on plant growth. In order to determine the most suitable sowing dates for different black cumin genotypes, an experiment was conducted in the open-field conditions of the Eastern Mediterranean region of Türkiye at Çukurova University, for two years, in 2020 and 2021, in three different sowing dates (October 15th, November 01st, and November 15th) with three different black cumin genotypes (Çameli cultivar (G1), Adana population (G2) and Iraq population (G3)). The findings of this research demonstrated significant differences in the agronomic characteristics and overall quality of black cumin. The main components were p-cymene (51.45%-66.33%), trans-4-Methoxythujane (8.40%-11.90%), thymoquinone (0.11%-19.26%), γ-Terpinene (1.28%-9.09%), and limonene (2.93%-4.50%). The main fatty acids were determined as linoleic acid (53.97%-57.56%), oleic acid (20.98-26.40), and palmitic acid (13.73%-15.02%). Consequently, the low number of flowers and the high temperatures observed in May, along with the early spring frosts, negatively affected the fertilization of the flowers. The seed yield was adversely affected because some of the seeds could not mature.

The Effects of Different Sowing Dates on Winter Wheat

Three separate field experiments, with different sowing dates, were conducted to determine a suitable sowing date for the highest agromorphological traits and tech- nological quality parameters. The results in growing season 2022–23 demonstrated the following: with a sowing date delay (i.e., with the second sowing date occurring on November 4, 2022), the grain yield was significantly advanced when compared to the first sowing date (occurring on October 13, 2022), while the grain yield was significantly increased in eight genotypes (out of a total of twelve of them) on the third sowing date (i.e., on November 14, 2022) when compared to the first. The rea- son for disproportions of grain yield on the first two sowing dates was the attack of barley yellow dwarf virus in autumn that seriously damaged more developed plants pertaining to the first sowing date, whereafter they were also more prone to other wheat diseases. The relative differences concerning the second sowing date with regard to the first one were as follow: an increase by 59.1% concerning the grain yield, by 6.3% concerning the test weight, and by 22.5% concerning a 1000 kernel weight, a decrease by 23.3% concerning the heading date, by 1.2% concerning the protein content, by 2.1% concerning the wet gluten content, and by 2.5% concerning the sedimentation value. The difference in grain yield between the second and the third sowing date amounted to 34.2% due to a premature senescence of plants in later sowing, as a result of increased June temperatures.

Effect of Seed Rate and Sowing Method on Seed Yield of Fennel

The present study was carried out at the research field of Spices Research Sub-Centre, Faridpur during Rabi season 2018-19. The experiment was done to determine the optimum seed rate and suitable sowing method for fennel cultivation to increase seed yield and quality of fennel. The experimental field belongs to high land of Low Ganges River Floodplain (AEZ 12) with clay loam in texture having 7.6-8.1 soil pH. The experiment was laid out in a Randomized Complete Block Design (factorial) with three replications. Four different seed rates viz., 6, 8, 10 and 12 kg seed/ha and two sowing methods viz., Broadcasting and Line sowing method were evaluated. All of all yield contributing parameters (number of plants per m2, number of branches per plant, number of umbels per plant, number of umbel lets per umbel, number of seeds per umbel let and seed yield (kg/ha) showed better result where seeds were sown at 10 kg/ha with line sowing method. Most of all yield contributing characters showed minimum results where seeds were sown at 6 kg seed/ha.The highest seed yield (1569 kg/ha) was recorded from the treatment combination of 10 kg seed/ha × line sowing method with highest benefit-cost ratio (2.9). The lowest seed yield (985.8 kg/ha) was recorded from 6 kg seed/ha × Broadcasting method with lowest benefit-cost ratio (1.87).

Effect of Varying Thermal Regimes on Yield and Yield Attributes of Mustard Varieties (Brassica juncea L.)

A field experiment was conducted at Agro-meteorological Research Farm, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, India during 2019-20. The experiment was conducted with Factorial Randomized Complete Block Design and replicated four times with nine treatment combinations consisting of three different sowing time D1 (31st October/23.5oC), D2 (10th November/23oC) and D3 (20th November/21oC) and three varieties V1 (Bio-902), V2 (NDR-8501) and V3 (Varuna). Results showed that higher growth and yield was observed when crop was sown on 31st October than other sowing times. Different thermal regimes were found to have a substantial impact on the yield attributes. Among the varieties Varuna gave highest growth and maximum yield as compared to other varieties due to fulfillment of congenial thermal Regime. Maximum utilization of heat from sowing to maturity was obtained when crop was sown on 31st October while minimum utilization of heat was obtained when the crop was sown on 20th November. Hence it can be concluded that the best sowing date of mustard is on 31st October in the early sowing. This study may help to select suitable sowing time under climatic condition of eastern Uttar Pradesh.

Agronomic assessment of the yield variability and yield gap of maize in Bhutan

Maize is the staple food crop in Bhutan, which has not achieved national food self-sufficiency. On-farm assessment of yield variability would provide insights into the priorities for Bhutan's maize development program. Here, we conducted three studies in Bhutan: a household survey, on-station experiment, and on-farm monitoring. First, we interviewed 100 households and collected information on maize crop management options and farming characteristics. Second, we evaluated maize growth at two research stations in different elevation zones (640 and 1,700 ​m a.s.l.). Third, we harvested maize from 25 farm fields at low and high elevations. The gaps between potential yield (with the best management practices at the research stations) and average farm yield and between the best and average farm yields were 53% and 23%, respectively, at the low elevation, and 23% and 20%, respectively, at the high elevation. The classification and regression tree (CART) model showed that field location (distance from the farmer's home), seed source (certified vs. self-produced), and the number of household members involved in farming were the key farming characteristics that affected yield variability, and the manure application regime, urea application, sowing method, and weeding frequency were key management practices. Our results suggest that future research should clarify the most suitable sowing methods and nutrient and weed management regimes, and identify optimal cultivars for each elevation zone, with the goal of developing crop management guidelines for smallholder farmers in Bhutan.

Effects of Temperature on Growth and Grain Maturity of Spring Maize in Northeast China: A Study of Different Sowing Dates

Situated at middle-to-high latitudes with limited thermal resources, Northeast China is the primary maize-producing region in China. It is also one of the regions most significantly impacted by climate change. Given the persistent impact of climate change, it is crucial to elucidate the effects of the varying thermal conditions and low temperatures for different sowing dates on the growth, development, and grain maturity of spring maize. To ensure secure maize production and disaster prevention, choosing the optimal sowing time for spring maize holds significant implications for the judicious utilization of climatic resources, risk mitigation, and the provision of meteorological guidance. Moreover, it can serve as a technical reference for relevant departments to conduct climate evaluation, disaster monitoring, prediction, and assessment, as well as impact analysis of corn production safety. Additionally, it can provide meteorological evidence to ensure food security and promote the sustainable development of modern agriculture. An interval sowing experiment of spring maize was conducted in Harbin in the north of Northeast China. Two varieties were used in the experiment. Four sowing dates were set, and the interval between adjacent sowing dates was 10 days. The local perennial sowing time, 5 May, was set as the second sowing date, with one date set later and two dates set earlier. During the experiment, the growth process, grain dry matter, seed moisture content, yield components, and temperature of spring maize were observed. The impact of temperature conditions on maize growth and yield formation was analyzed in this paper through mathematical statistics, which further led to the establishment of a monitoring and evaluation model for assessing the effect of thermal conditions and temperature on maize. The results showed that the growth rate of spring maize was closely related to temperature. When the average temperature, minimum temperature, and maximum temperature increased by 1 °C, the average emergence rate increased by 1.05%, 0.99%, and 1.07%, respectively, and the average vegetative growth rate increased by 0.16%, 0.16%, and 0.09%, respectively. The change rate of ≥10 °C active accumulated temperature was significantly correlated with the change rate of the dry weight of the grain kernel, which conformed to the quadratic equation of one variable. The temperature influence coefficients of different sowing dates varied from 1.0% to 1.7%. The relationship between the accumulated values of 10 ℃ active accumulated temperature and the grain moisture content of spring maize was a logarithmic function. From 10 to 50 days after anthesis, the effect of temperature can explain about 95% of the change in grain moisture content. After physiological maturity, the effect of thermal conditions can only explain 56–83%. The temperature influence coefficient ranges from 1.3% to 13.8%. Comparatively speaking, the second sowing date is the most suitable sowing date. Early sowing is prone to encounter low temperatures, resulting in underutilization of the early heat, while late sowing is prone to less heat. Both conditions are not conducive to better improve the yield of spring maize.

The Effect of Sowing Date on the Nutritional Quality of Kernels of Various Maize Varieties in Northeast China

Suitable sowing dates are crucial in plant production to cope with climate change and ensure high-quality crop production. We hypothesize that the analysis of the effect of sowing date and climatic resources on maize kernel nutritional quality (KNQ) (crude fiber, starch, crude fat, and crude protein) might contribute to selecting appropriate sowing dates according to different production requirements and meteorological conditions. The study was based on five main local varieties in three experimental stations (early-maturing variety: Zengyu1317, Hongshuo298, Keyu15; medium-maturing variety: Xianyu335; late-maturing variety: Danyu405) in Northeast China from 2018 to 2021. The results showed that: (1) the average starch content (67.7%) and crude protein content (9.1%) of early-maturing variety maize and the crude fiber content (3.3%) and crude fat content (3.6%) of late-maturing variety maize were the highest in Northeast China; (2) the sowing date had no significant effect on the starch content, but significantly affected the crude protein and crude fiber contents, the kernel protein content of early-maturing variety maize was the highest when the sowing date was delayed for 5 days (9.8%), and the crude fiber content of medium-maturing and late-maturing variety maize (4.3% and 5.39%, respectively) was the highest when the sowing date was advanced by 10 days; (3) during the reproductive growth stage, the more light and heat resources, the less starch content and crude protein content and the more crude fat content; when the diurnal temperature range increased by 1 °C, the crude fat content decreased by 0.28%, and the crude protein content increased by 0.77%; for every 100 mm more precipitation, crude fiber and crude protein content decreased by 0.68% and 0.73%, respectively, and fat content increased by 0.15%. Our results provide a meaningful reference for maize production to cope with climate change and improve kernel quality.

OFF-SEASON MAIZE YIELD FORECASTING FOR DIFFERENT SOWING DATES

Brazil is the world's third-largest maize producer. Its yield is influenced by climate, soil conditions, management and their interactions. Identifying the most suitable sowing window and using yield forecasting systems allows for increased yields and better harvest management. Crop simulation models can be used to assess crop responses to various conditions. This study aimed to identify the most favorable planting date for off-season maize by using the DSSAT CSM-CERES-Maize model for Jataí, Goiás state. Using meteorological data from 1986 to 2015, eight productivity forecasting strategies were tested. The results of the model application at different sowing dates indicated that the dates in January tended to present a more favorable attainable yield (Ya), i.e., values closer to the potential yield (Yp) of the crop, whereas in February, Ya were affected by lower precipitation from April to June. The best date for maize sowing was January 25th. The simulations indicated the possibility of predicting the off-season maize productivity in Jataí with high precision and accuracy up to 30 days prior to harvest (R² ≥ 0.81, d ≥ 0.90, and c ≥ 0.81).

Design and Experimental Testing of a Centrifugal Wheat Strip Seeding Device

Wheat sowing has the characteristics of wide and short sowing periods, and there are situations in which the suitable sowing period is missed. In order to meet the needs of high-speed sowing, a centrifugal wheat strip seeding device was designed, the principle of which is that rotating parts were mainly composed of centrifugal concave plate and guide strip rotating in the shell to provide the mechanical force and drive the airflow and then realize high-speed seeding. The influence of the rotational speed of the seed discharging plate, the seed feed rate, and the dip angle of the guide strip on the distribution of the flow field and trajectory of seeds in the device was analyzed. The aerodynamic characteristics of seeds and the distribution of the gas-phase flow field inside the seed displacer under airflow were analyzed by CFD–DEM coupled simulation. The effects of three operating parameters on the coefficient of variation of sowing uniformity (CVSU) and the row-to-row seeding amount coefficient of variation (RSCV) were clarified, and the simulation results were verified by bench experiments after secondary optimization. When the centrifugal concave plate rotational speed, seed feed rate, and guide strip angle were 408 rpm, 4938 grains/s, and 69°, the results showed that CVSU and RSCV were 1.12% and 2.39%, respectively, which was in line with the standards for grain strip seeders stipulated. The designed seed discharge device can sow 3.4 ha per hour. This study provides a reference for research of centrifugal airflow-assisted high-speed seeding devices for wheat.

Effect of sowing dates on physiological characteristics, yield, and quality of Carthamus tinctorius

A field experiment was conducted to measure the physiological characteristics, yield, active ingredient content, and other indicators of Carthamus tinctorius leaves undergoing 13 sowing date treatments. The principal component analysis(PCA) and redundancy analysis were used to analyze the correlation between these indicators to explore the effect of sowing date on the yield and active ingredient content of C. tinctorius in Liupanshan of Ningxia. The results illustrated that the early sowing in autumn and spring had significant effects on leaf photosynthetic parameters, SPAD value, antioxidant enzyme activity, nitrogen metabolism enzyme activity, filament yield, grain yield, and hydroxy safflower yellow A(HYSA) of C. tinctorius. Sowing in mid-November and late March had the best effect. Leaf transpiration rate, stomatal conductance, nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate synthase increased by 44.9%, 52.4%, 15.9%, 60.8%, 10.3%, and 38.3%, respectively. The activities of superoxide dismutase, peroxidase, and catalase decreased by 10.8%, 4.1%, and 20.9%, respectively. The improvement of photosynthetic physiological characteristics promoted the dry matter accumulation and reproductive growth of C. tinctorius. The yield of filaments and seeds increased by 15.5% and 11.7%, and the yield of HYSA and kaempferol increased by 17.9% and 20.0%. In short, the suitable sowing date can promote the growth and development of C. tinctorius in Liupanshan of Ningxia, and significantly improve the yield and quality, which is conducive to the high quality and efficient production of C. tinctorius.

Effect of Different Sowing Dates and Row Spacing on Growth and Yield of Faba Bean under Khumaltar Environment

Faba bean (Vicia faba L.) is an annual minor grain legume locally known as Bakulla. An experiment on sowing dates and different row spacing was conducted at the National Agronomy Research Centre (NARC) Khumaltar from 2019/20 to 2021/22 to identify suitable sowing dates and row spacing. Three sowing dates (October 24, November 7, and November 21), row spacings (30 cm, 45 cm, and 60 cm), and plant-to-plant spacing of 10 cm were evaluated in a split plot with four replications. Plot size was maintained at 7.2 m2 (2 m x 3.6 m), the variety used was local, and the fertilizer dose applied was 20:40:20 N: P2O5:K2O kg ha-1. At physiological maturity, five plants per plot were sampled randomly for measurements of plant height, number of pods per plant, unfilled pods/plant, and 100 seed weight. Data on 50% flowering, days to 90% maturity, plant height, number of pods per plant, green pod yield, biological yield, and hundred seed weight were recorded. Combined analysis showed that sowing dates significantly influenced days to 50% flowering, final stand/m2, plant height, number of branches per plant, and number of pods per plant. The final stand/m2, plant height, straw dry matter, seed yield, and hundred seed weight were affected significantly by various row spacing. There was no significant interaction effect between sowing dates x row spacing, and all three factors (sowing dates x spacing x year) also had no significant interaction. The year they have significantly influenced all the parameters except 90% maturity and number of pods per plant. Sowing dates x year and spacing x year did not significantly influence all the parameters. Crop sown on October 24 produced the highest grain yield (1571 kg ha-1), followed by November 21 (1354 kg ha-1). Grain yields were significantly higher in 30 cm row spacing (1825 kg ha-1), mainly due to higher plant population per m2 than in 60 cm row spacing. It was concluded that the last week of October and 30 cm row spacing is suitable for faba bean production.

Effects of Sowing Date Variation on Winter Wheat Yield: Conclusions for Suitable Sowing Dates for High and Stable Yield

Timely sowing and harvesting play important roles in agricultural production. The appropriate management decisions are necessary to cope with climate change and ensure high and stable crop yields. This study analyzed the effects of sowing date on the growth process of winter wheat and quantified the effects of climate resources and photothermal potential yield on theoretical yield at different stages of winter wheat. The analysis was based on the data from winter wheat interval sowing experiments conducted at the Hebei Gucheng Agricultural Meteorology National Observation and Research Station (Gucheng station) in north China (115°40′ E, 39°08′ N) during 2017–2019. The results showed that: (1) with the delay in sowing date, the growth process of winter wheat significantly advanced, the proportion of vegetative growth period significantly reduced (0.19% for per day delay), the proportion of reproductive growth period (RGP) significantly increased (0.12% for per day delay), and the prewintering light and temperature resources significantly reduced (12.2 °C·d accumulated temperature and 19.0 MJ·m−2 solar radiation for per day delay); (2) the theoretical yield of winter wheat showed a significant exponential relationship with the photothermal potential yield of the whole growth period: the minimum photothermal potential for yield formation was 26.6 t·ha−1, and the maximum theoretical yield was 12.6 t·ha−1; and (3) the wheat yield and yield stability were highest when the RGP photothermal potential yield was 16.0 t·ha−1 and the prewintering active accumulated temperature was 400 °C·d. This study also proposed a method to estimate the suitable sowing and harvesting dates to achieve high and stable yield of winter wheat, showing that the suitable sowing dates of winter wheat at Gucheng station from 1997 to 2021 ranged from 1 to 15 October, with no significant interannual variation; the suitable harvesting period ranged from 5 June to 10 July and showed a trend of gradual advance with the delay of the year. The results of the study provide a reference for sowing date adjustment of crops to adapt to climate change.

Effect of accumulated temperature before overwintering on wheat seedling growth status in north winter wheat area of China.

To explore the impacts of global climate change on the suitable sowing date for winter wheat in north winter wheat area of China, we carried out a wheat sowing date experiment during growing seasons of 2019-2021 at the Beijing Experimental Base of the Institute of Crop Sciences, CAAS. Two winter wheat cultivars with different tillering powers were selected as experimental materials. Four different sowing dates were set: September 25th (J), October 5th (S0), October 15th (S1) and October 25th (S2), to examine the responses of population quality, individual characters, and stem and tiller physiology to the accumulated temperature difference before overwintering. The results showed that with the delay of sowing date, the accumulated temperature before winter and their difference between the adjacent sowing dates decreased gradually. The accumulative temperature at the sowing J and S0 both exceeded 550 ℃, which met the basic condition for the formation of strong wheat seedlings before winter. The average accumulated temperature at sowing S1 and S2 was 148.0 and 282.4 ℃ lower than that of S0, which was not conducive to the establishment of strong wheat seedlings before winter. The average accumulated temperature decreased by 204.0, 148.0 and 134.4 ℃, when the sowing date was delayed by 10 days under the four different sowing dates, respectively. The days from sowing to emergence were affected by the average daily temperature. The days from sowing to emergence gradually increased with the delay of sowing date when the daily average temperature was lower than 15 ℃, while the days from sowing to emergence were constant when the daily average temperature was higher than 15 ℃. The total stem number, leaf area index, dry matter weight, nitrogen accumulation and tiller number per plant of wheat also decreased with the decreases of pre-winter accumulated temperature. The soluble sugar content and nitrate reductase activity at the seedling increased first and then decreased with the decreases of accumulated temperature before winter, while the soluble protein content and glutamine synthetase activity to accumulated temperature performed differently among varieties. According to the population quality and individual traits of wheat before winter, among the four different sowing dates, the total stem number and tiller number per plant of wheat before sowing on October 5 were the closest to the standard of strong seedlings before winter in north winter wheat area. The accumulated temperature before winter is conducive to the formation of strong seedlings. When the daily average temperature is 15-17 ℃, it is the best sowing time for winter wheat in Beijing.

Effects of Mixed Planting on Machine Transplanting Adaptability and Grain Yield of Hybrid Rice

Because the current hybrid rice machine transplanting sowing quantity is too large and the high rate of missing hills or poor seedling quality during mechanical transplanting, the mechanized planting of hybrid rice is limited, which results in significant hindrance of large-scale planting of hybrid rice in China. In this study, a mixed sowing technology (replacement of a portion of hybrid rice seeds with conventional rice seeds) in seedling cultivation was adopted to determine the appropriate variety combinations and conventional rice sowing quantity using a variety combination experiment and sowing quantity experiments, respectively. The results of the variety combination experiment showed that combinations of Changyou 4 mixed with Nanjing 5055, and Yuanliangyou mixed with Yangdao 6 could reduce the sowing quantity of hybrid rice, improve the quality of machine transplanting, and not reduce the grain yield. The results of the conventional rice sowing quantity experiment showed that with the increase in conventional rice sowing quantity, the seedling quality, spikelet per panicle, and filled kernel percentage decreased, and the mechanical transplanting quality improved. Compared with pure sowing hybrid rice, the grain yield was not significantly different in the japonica rice treatment when the sowing quantity of Nanjing 5055 was more than 75 g/tray and Yangdao 6 was more than 60 g/tray. With the increase in conventional rice sowing quantity, the missing hill rate decreased significantly and the seedling density increased significantly, so that the panicle number was also improved, which might have compensated the reduction in seedling quality, spikelet per panicle, and filled kernel percentage. As a whole, 90 g Nanjing 5055 seeds mixed with 30 g Changyou 4 seeds per tray and 75 g Yangdao 6 seeds mixed with 30 g Yuanliangyou seeds per tray were suitable sowing quantities for mixed planting that could ensure strong seedlings and better mechanical transplanting quality, while reducing the cost (reduce the sowing quantity of hybrid rice and conventional rice) without reducing the grain yield.

A Simulation Study on Optimization of Sowing Time of Maize (Zea mays L.) for Maximization of Growth and Yield in the Present Context of Climate Change under the North China Plain

Adjusting the sowing dates of crops is an effective measure for adapting them to climate change, but very few studies have explained how the optimum sowing dates can be determined. In this study, we used the sowing date field data from 2018 to 2021 from Hebei Gucheng Agricultural Meteorology National Observation and Research Station to analyze the effects of the sowing date on growth, development, and yield of maize, and to quantify the impact of light-temperature potential productivity on different stages of the yield formation. The results showed that delayed sowing decreased the vegetative growth period (VGP) and increased the reproductive growth period (RGP) of maize. The light-temperature potential productivity of the whole growth (WG) period had an exponential relationship with the theoretical yield. At least 14,614.95 kg ha−1 of light-temperature potential productivity was needed to produce grain yield. The maximum theoretical yield was approximately 18,052.56 kg ha−1, as indicated by the curve simulation results. The influence of light-temperature potential productivity on theoretical yield was as follows: VGP > RGP > vegetative and reproductive period (VRP). Accordingly, a method for determining the sowing time window based on VGP was established, and the optimal sowing dates were estimated for 1995–2021 and the SSP2-4.5 scenario in CMIP6 in the middle of this century (2030–2060). The simulation results showed that the optimum sowing date of maize “Lianyu 1” at the study site was 20–25 May in 1995–2021. In the middle of this century, the optimal sowing time of maize was ahead of schedule and the suitable sowing window was increased slightly. We conclude that advancing the sowing date of maize is a practical strategy for enhancing yield in the context of climate warming, and this strategy will provide a meaningful reference for scientific optimization of sowing dates to adapt maize to climate change.

A critical analysis of the effect of projected temperature and rainfall for differential sowing of maize cultivars under RCP 4.5 and RCP 6.0 scenarios for Punjab

A simulation study was conducted for two maize cultivars (PMH1 and PMH2) under two Representative Concentration Pathways (RCPs) in four agroclimatic zones of Punjab state of India where climate change depicts a consistent rise in temperature and variability in rainfall. The temperature and rainfall varied from location to location so agroclimatic zone II (Ballowal Saunkhri), zone III (Ludhiana, Amritsar, and Patiala), zone IV (Bathinda), and zone V (Abohar and Faridkot) were selected for the study. The bias-corrected ensemble model data from seventeen global circulation models (GCMs) for RCP 4.5 and RCP 6.0 was used to simulate maize yield for a period of 70 years (2025–2095) using calibrated and validated CERES-Maize model. The simulated yield trend in Punjab under current dates of sowing indicated a strong negative correlation between the yield and the weather parameters under the two scenarios. Agroclimatic zones II, III, and V (Faridkot) observed an increase in temperature by 1 °C over the 70 years’ time period which led to lowering of the maize yield from high yield category (> 5000 kg/ha) to low (< 3000 kg/ha). The cv PMH1 was able to compensate these effects and performed better in agroclimatic zones II, III, and V (Faridkot). In agroclimatic zones IV (Bathinda) and V (Abohar), an increase in temperature by 2 °C is observed, which led to decline of yield categories from medium yield years to low yield years. Though the rainfall in the region was higher for low yield years, but the rainfall amount was insufficient to mitigate the impact of temperature. Under the future stabilization scenarios, amongst the current sowing dates, mid-June was found suitable in agroclimatic zones II and III and in agroclimatic zone V (Faridkot) both early and mid-June sowing dates performed well. Considering the suitable sowing dates under current farming practices, it would be easy to determine the future sowing window for maize cultivars in Punjab.

Allometric dynamics of Sinapis alba under different ecological conditions

ObjectivesThe indigenous oilseed crops are facing the problems of insects, diseases attack with poor yield potential. Canola needs high water requirement and also > 50 % shattering losses. Therefore, farmers are compelled to cultivate alternative crops. Sinapis alba is the best replacement of winter rapeseed due to superior phenotypic plasticity for dry temperate climate like Pakistan Pertinent sowing time augments the soil and climatic resources efficiency in a specific ecological zone to expose various phenological stages for appropriate growth and development to achieve potential yield. MethodsField experiments were performed to appraise the suitable sowing date at three locations (NARC, SAWCRI and Talagang) in Pothwar plateau of Pakistan. Six sowing dates from 1st October up to 15th December with fifteen days interval were quart replicated in RCBD during two 2017–18 and 2018–19. Explicated environment of various locations prudently influenced Sinapis alba performance and yield attributes to accomplish potential yield during both years. Among sowing dates, 15th October enormously promoted morphological development to attained maximum mean values of pods plant−1, 1000-seed weight, biological yield and seed yield. Among locations, SAWCRI nurtured highest number of plants−2, plant height, primary and secondary branches, pods plant−1, seed pod-1, 1000-seed weight, biological yield and seed yield. Variability in Agro-meteorological indices of three locations significantly influenced the interactive effect of year × location × sowing dates for growth and yield attributes of Sinapis alba. It was observed that 15th October sowing at SAWCRI attained 2.25 t ha−1 seed yield that was 10.9 % and 24.4 % higher from the optimal dates at NARC and Talagang that accomplished 84.43 %. 91.12 % and 95.76 % more yield from the delayed (15th Dec) sowing at three locations. ConclusionBetter coordination of soil and climatic conditions with 15th October sowing for growth and development signified the monumental importance of optimal sowing date as the benchmark of superior crop productivity to improve the livelihood of the farmers.