Maize Sowing Research Articles

Sowing Environments and Yield of Maize (Zea mays L.) Cultivars under Changing Climate Conditions of North Western Himalayan Region

Sowing dates, as one of the primary agronomic practices have significant influence over yield of maize especially during the times of climate change. Therefore, the present field investigation was conducted during the Kharif cropping seasons of 2013 and 2014 to evaluate different sowing dates for their influence over maize (Zea mays L.) yield. The field experiment was conducted in a randomized block design with factorial arrangement consisting of four dates of sowing and three maize cultivars. The study results revealed that sowing of crop by 10th June can have taller plants (261.5 and 265.2 cm for 2013 and 2014, respectively), significantly better yield contributing characters of maize such as number of cobs per plant (1.1 and 1.1 for 2013 and 2014, respectively), number of grains per cob (258.7 and 268.3 for 2013 and 2014, respectively) and test weight (268.5 and 271.6 grams for 2013 and 2014, respectively). Similarly, the significantly higher maize grain (57.3 and 60.1 quintal/hectare for 2013 and 2014, respectively) and stover yield (108.8 and 109.2 quintal/hectare for 2013 and 2014, respectively) was recorded with sowing of maize crop by 10th June. Among the maize cultivars, HQPM-1 resulted in substantially higher maize grain (53.9 and 56.5 quintal/hectare for 2013 and 2014, respectively) and stover yield (102.9 and 104.1 quintal/hectare for 2013 and 2014, respectively). Based on the present field investigation, it can be concluded that sowing of maize by 10th June and maize cultivar HQPM-1 can be recommended for better yield levels under the given conditions of North-western Himalayas.

Effects of long-term saline water irrigation on soil salinity and crop production of winter wheat-maize cropping system in the North China Plain: A case study

Fresh water shortage is a major problem for grain production in the low plain around Bohai Sea in the North China Plain. Relative abundance of shallow saline groundwater could serve as an alternative water resource for use during dry seasons. A continuous 8-year field study was conducted from 2015 to 2023 to assess the effects of salt content in irrigation water on soil salt accumulation and crop production. Fresh water (FW) with electrical conductivity (EC) at 1.6 dS/m and three levels of saline water (SW) with EC at 4.7 (SW1), 6.3 (SW2) and 7.8 dS/m (SW3) were used for irrigation. Results showed that a single irrigation event at the jointing stage of winter wheat increased grain production averagely by 18.6 %, 22.5 %, 12.9 % and 9.5 % compared with a rain-fed treatment (RF) under FW, SW1, SW2 and SW3, respectively. With an additional irrigation applied at flowering stage, both irrigations using FW increased the yield by 28.6 %, and both irrigations using SW2 increased the yield by 19.3 % compared with RF. Negative effects of salt on winter wheat overshadowed the positive effects of increased water supply under two irrigations both using SW. With an irrigation at maize sowing and the subsequent summer rainy season, the yield of maize following winter wheat was not affected by a one-time SW irrigation to the previous crop, but showed a 5.3 % yield reduction when two irrigations of SW were applied. There was no apparent salt accumulation in the top 1 m of the soil profile, but a slight increasing trend in the salt content in the 1–2 m layer of the soil profile under SW2 and SW3 irrigation. No apparent changes in soil physical properties were observed for continuous application of SW. It was suggested that SW with EC not exceeding 6.3 dS/m should be applied for a single irrigation during the winter wheat season. This practice could alleviate the fresh water shortage in this region and allow for the maintenance of a relatively stable yield of winter wheat and maize without the risk of salt accumulation in the soil.

Maize yield and Fall armyworm damage responses to genotype and sowing date-associated variations in weather conditions

Due to climate disruption and delayed onset of rains, maize is often sown late, outside the optimal window, increasing the impact of pests such as fall armyworm and reducing yields. Identifying optimal sowing dates and the best genotypes is crucial to maximise yields while limiting fall armyworm (FAW) damage. Thus, this study was undertaken to evaluate yield and FAW damage variation in relation to sowing-date weather conditions to determine the optimal sowing window. The experiment had a split-plot design with four genotypes ('PVAH-1 L', 'PVAH-3 L', 'PVAH-6 L' and 'SAM 4 VITA') and four sowing dates (30 November to 14 January and delayed by 15, 30 and 45 days) during the three consecutive cropping seasons. Abundant rainfall and a high number of wet days increase yields while reducing FAW damage. The genotype shows that 'PVAH-1 L' has ear resistance (3.24) and leaf partial resistance (4.05) to FAW, with a high yield (6.54 t.ha−1). In contrast, 'PVAH-3 L' (4.27 and 5.05), 'PVAH-6 L' (4.24 and 4.37) and 'SAM 4 VITA' (4.25 and 4.00) show partial resistance to FAW in both ears and leaves, but have relatively lower yields, except for 'PVAH-6 L' (6.29 t.ha−1). Maize sown on 15 December had a high yield (8.76 t.ha−1), similar to those sown on 30 November. However, sowing on 30 December and 14 January reduced yields by 2 t.ha−1 and 7 t.ha−1 respectively, while increasing FAW infestation and damage. Therefore, in the Lubumbashi region, due to the delayed onset of rains and climatic disturbances, the sowing period can be extended to 30 December, with an optimal window extending from 30 November to 15 December. To maximise yields and limit FAW damage, it is recommended that 'PVAH-1 L' be sown on 15 December, 'SAM 4 VITA' on 30 November or 15 December and 'PVAH-6 L' on 30 November or 15 December.

Utilization of Diversified Cover Crops as Green Manure-Enhanced Soil Organic Carbon, Nutrient Transformation, Microbial Activity, and Maize Growth

Studying green manure in several returning methods to enhance soil fertility and crop benefits is a strong foundation for cropland nutrient management. However, how different types of green manures and their variable doses affect the efficacy of applied manures, either buried or mulched, remain overlooked. The objective of this study was to optimize green manure management to enhance soil fertility and maize biomass using five types of green manures (white mustard, forest rye, fiddleneck, sufflower, and pea) in two different doses (low, 5 g per pot, and high, 10 g per pot), which were either buried or mulched before and after maize sowing. Results revealed that total carbon content increased due to green manure treatments, representing a 10% increase over control, particularly through buried w. mustard (10% increase before maize cultivation) and mulched safflower and pea (12% and 11% increase after maize cultivation over control). Dry maize aboveground biomass yields also improved across all variants, with buried mustard yielding 18.4 g·plant−1 (compared to 8.6 g·plant−1 in the control), mulched mustard yielding 16.4 g·plant−1, and buried pea yielding 17.8 g·plant−1. Green mulching generally acidified the soil (pH 5.71 compared to 6.21 in the control), except for buried fiddleneck (pH 6.39 after maize cultivation) at a high dose of manures. Carbon-mineralizing enzyme activities (dehydrogenase and β-glucosidase) were significantly increased by green manures, with buried fiddleneck showing a 22.6% and 20.6% increase over the control, and mulched fiddleneck showing a 24.5% and 22.4% increase under high doses. The study suggests that partially decomposed and mineralized mulched biomass may induce a negative priming effect on carbon-mineralizing enzymes due to a decrease in the C/N ratio of the soil. It emphasizes that the nutrient content and stoichiometry of green manures, alongside soil characteristics such as the C/N ratio, are critical factors for sustainable soil management and carbon sequestration. These findings underscore the need for careful selection and management of green manures to optimize soil health and carbon-storage outcomes.

Effect of Prolonged Action of Mineral Fertilizers under Conditions of Temperature Stress on Silage Maize Yield in the Steppe Zone of the Southern Urals

In modern agriculture in the Southern Urals, an important agronomic technique is to counteract drought. Of particular importance in increasing the feed base is the cultivation of maize for silage, which ensures maximum yields in extreme conditions. The aim of the study was to determine the potential possibilities of increasing the yield of green mass of maize for silage under the influence of temperature stress in conjunction with the prolonged action of mineral fertilizers and precursors in arid conditions. The study was carried out in the central zone of the Orenburg region from 1993 to 2022 on a stationary site with the southern carbonate heavy loamy chernozem soils with a humus content of 3.2–4.0%. The experiment was carried out with and without mineral fertilizers. The content of nitrate nitrogen in the soil was determined by the ionometric method of Tyurin, mobile phosphorus – by Machigin, exchangeable potassium – by Maslova. A thermostatic-weight method was used to determine soil moisture. On average, over 30 years of research, when cultivating maize for silage in a 6-field crop rotation, an increase in yield was noted with the use of mineral fertilizers from 0.23 to 0.84 t/ha. The annual application of mineral fertilizers in permanent sowing of maize provided an increase in the yield of green mass of 2.51 t/ha. In years with severe aridity, the yield of leaf-stem mass on a fertilized background decreased by an average of 1.61 t/ha. In very dry years, maize plants consumed less nitrate nitrogen (by 2 or more times) than in years with different humidity, but at the same time, potassium consumption increased.

Impact of mechanical weed control on soil N dynamics, soil moisture, and crop yield in an organic cropping sequence

Mechanical weed control is a major element of weed suppression in organic farming systems. In addition to the direct effect on weed growth, mechanical weeding, such as harrowing or hoeing, is known to induce side effects on several soil- and crop-related properties. In this study, we investigated the impact of mechanical weeding on soil mineral nitrogen (SMN), soil moisture, and crop yield in an organic crop rotation of grass-clover (Lolium multiflorumLam., Trifolium pratense L.), silage maize (Zea mays L.) and winter barley (Hordeum vulgare L.). The experiment was conducted in two consecutive years (2021, 2022), where each crop was grown in each year on a Plaggic Anthrosol with sandy loam in North-West Germany. Two weed control treatments (mechanical: harrowing, hoeing; chemical: herbicide application) were implemented in a randomized block design with four replications. Greater net nitrogen (N) mineralization in maize compared to winter barley were attributed to the incorporation of grass-clover residues before sowing of maize and greater mineralization potential during the maize growing season. Higher weed growth in maize after mechanical weeding resulted in a reduction of up to 47% in SMN content in the topsoil. In barley, no differences in weed suppression were observed between the treatments and only small effects on SMN were determined after mechanical weeding. The soil water content in the mechanically weeded plots was significantly higher at several events in both years and for both crops, which was attributed to increased water infiltration by disrupting the soil crust. Neither crop yield nor N uptake in harvest products was affected by the different treatments.

Intercropping maize (Zea mays L.) and field beans (Vicia faba L.) for forage, increases protein production

In 2005–2007, a field study was conducted into intercropping of maize with faba bean at Pawlowice research station, Wroclaw University of Environmental and Life Sciences. The main aim of the multi-year field research was an investigation into the reactions of differing maize hybrid earliness to intercropping cultivation with faba bean. The field research evaluated the effect of three maize hybrids—Wilga (early—E), Blask (medium—M) and Iman (late—L)—and the sowing rate of faba bean—18 (Fb1), 27 (Fb2) and 36 (Fb3) seeds per 1 m2—on growth dynamics and yield structure, and biomass, protein, and energy yield. Cultivation of faba bean in maize inter-rows led to significant competition with maize and affected yields, causing a decrease in maize dry matter yield from 14.1 (Fb1) to 20.6% (FB3) compared with maize sown alone. In terms of total biomass yield from maize and faba beans, no significant differences were found, but a slight increase in yield of 1.1–4.2% (repective to Fb1 and Fb3) was noted compared to maize sown alone. The early maize hybrid had a significantly lower yield but was most suitable for intercropping with faba bean. The dry biomass yield of early hybrids increased in intercropping by 25% compared to pure maize cultivation. Total protein yield from both intercropping components was higher than in the pure sowing of maize: from 24 (Fb1) to 39% (Fb3). The increase in protein production resulted in an improvement in the energy–protein ratio. The number of UFL per kg of total protein decreased from 13.2 in pure maize cultivation (M-P) to 9.3 (Fb3). A more balanced forage biomass was produced from intercropping maize with faba bean, especially when an early maize hybrid was sown with faba beans.

Variations in Primary Nutrients and Sowing Dates Influence Performance of Monsoon Maize (Zea Mays L.) in Punjab, India

ABSTRACT Maize, being a nutritious and multipurpose crop requires proper nutrition (N, P, and K) and standardization of sowing time to enhance productivity and profitability under changing climate scenario. Therefore, a field experiment was conducted during monsoon season of 2021 and 2022 at agricultural farm, Lovely Professional University, Punjab, in split plot design with four fertilizer levels (125, 100, 75, and 50% recommended dose of fertilizers; RDF) in main plots and four sowing dates (15 and 30 of June and July) in subplots, replicated thrice. Maize sown on 30 June and fertilized with 125% RDF ensured higher growth attributes throughout crop growth. Besides, comparatively greater yield attributes as well as grain yield (8.22 t ha−1), stover yield (11.86 t ha−1), and harvest index (40.9%) were observed from that treatment combination, and it also recorded higher quality protein and nutrient uptakes but less residual soil fertility. Maize grown on 30 July under application of 50% RDF was the poorest yielder. Further, production economics and energy analysis showed similar trend and indicated that maize grown on 30 June under application of 125% RDF recorded maximum gross return (₹168275 ha−1), net return (₹109565 ha−1), and benefit-cost ratio (2.87) as well as energy output (269084 MJ ha−1) and net energy gain (250750.3 MJ ha−1).

Maize miRNAs and their putative target genes involved in chilling stress response in 5-day old seedlings

BackgroundIn the context of early sowing of maize as a promising adaptation strategy that could significantly reduce the negative effects of climate change, an in-depth understanding of mechanisms underlying plant response to low-temperature stress is demanded. Although microRNAs (miRNAs) have been recognized as key regulators of plant stress response, research on their role in chilling tolerance of maize during early seedling stages is scarce. Therefore, it is of great significance to explore chilling-responsive miRNAs, reveal their expression patterns and associated target genes, as well as to examine the possible functions of the conserved and novel miRNAs. In this study, the role of miRNAs was examined in 5d-old maize seedlings of one tolerant and one sensitive inbred line exposed to chilling (10/8 °C) stress for 6 h and 24 h, by applying high throughput sequencing.ResultsA total of 145 annotated known miRNAs belonging to 30 families and 876 potentially novel miRNAs were identified. Differential expression (DE) analysis between control and stress conditions identified 98 common miRNAs for both genotypes at one time point and eight miRNAs at both time points. Target prediction and enrichment analysis showed that the DE zma-miR396, zma-miR156, zma-miR319, and zma-miR159 miRNAs modulate growth and development. Furthermore, it was found that several other DE miRNAs were involved in abiotic stress response: antioxidative mechanisms (zma-miR398), signal transduction (zma-miR156, zma-miR167, zma-miR169) and regulation of water content (zma-miR164, zma-miR394, zma-miR396). The results underline the zma-miRNAs involvement in the modulation of their target genes expression as an important aspect of the plant’s survival strategy and acclimation to chilling stress conditions.ConclusionsTo our understanding, this is the first study on miRNAs in 5-d old seedlings’ response to chilling stress, providing data on the role of known and novel miRNAs post-transcriptional regulation of expressed genes and contributing a possible platform for further network and functional analysis.

Spatial and temporal distribution of optimal maize sowing dates in Nigeria.

Climate change and inter-annual variability cause variation in rainfall commencement and cessation which has consequences for the maize growing season length and thus impact yields. This study therefore sought to determine the spatially explicit optimum maize sowing dates to enable site specific recommendations in Nigeria. Gridded weather and soil data, crop management and cultivar were used to simulate maize yield from 1981-2019 at a scale of 0.5°. A total of 37 potential sowing dates between 1 March and 7 November at an interval of 7 days for each year were evaluated. The optimum sowing date was the date which maximizes yield at harvest, keeping all other management factors constant. The results show that optimum sowing dates significantly vary across the country with northern Nigeria having notably delayed sowing dates compared to southern Nigeria which has earlier planting dates. The long-term optimal sowing dates significantly (p<0.05), shifted between the 1980s (1981-1990), and current (2011-2019), for most of the country. The most optimum planting dates of southern Nigeria shifted to later sowing dates while most optimum sowing dates of central and northern Nigeria shifted to earlier sowing dates. There was more variation in optimum sowing dates in the wetter than the drier agro-ecologies. Changes in climate explain changes in sowing dates in wetter agro-ecologies compared to drier agro-ecologies. The study concludes that the optimum sowing dates derived from this study and the corresponding methodology used to generate them can be used to improve cropping calendars in maize farming in Nigeria.

Development of A Robotic Maize Seed Planter

The automatic maize seed planter design to address the limitations of traditional planting techniques and reduce the lead time in agricultural processes and enhance the output. The research encompasses a comprehensive study of maize sowing techniques, challenges, and advancements in agricultural robotics. The literature review explores the limitations of traditional maize sowing techniques, such as inaccurate seed placement, labor intensiveness, and weather dependence. The construction process involves the integration of a chassis, wheels, sensors, microcontroller, and seed dispensing system. The software component utilizes a custom algorithm to control the movement and seed placement of the robot. Experimental testing and evaluation were conducted to assess the performance of the robot. The accuracy of seed placement was determined by analyzing the deviation from the desired spacing. The efficiency of the robot was measured by comparing the time taken for sowing with traditional methods. The results demonstrated that the automatic maize seed planter achieved high accuracy in seed placement with minimal deviation from the desired spacing. The results validate the effectiveness of the robotic system in addressing the limitations of traditional sowing techniques and demonstrate its potential to revolutionize the agriculture industry. The objectives are to develop a cost-effective, efficient, and accurate maize seed planter and implement the design in the fabrication. Recommendations for further work is real-time mapping and monitoring. Real-time mapping and monitoring of the field can help the robot navigate the field more efficiently and accurately.

Efficacy of Sowing Dates in Growth and Yield of Hybrid Maize under Namsai Conditions

The study was conducted in the instructional and research farm during the period 10th February to 11th September 2023 in a randomized block design (RBD) method. The first sowing dates started on 10th February, followed by 20th February, 2nd March, 12th March, 22nd March, 1st April, 11th April, 21st April, 1st May and 11th May, respectively, at 10 days intervals. The growth parameters like seed germination, number of leaves per plant, plant heights, number of cobs per plant, number of grains per cobs, 100 grain seed index, leaf area index and grain yield per hectare has been observed and evaluated. On evaluation it was noted that maize sown on 1st April gave highest seed germination of 95.87%, tallest plant of 198.83 cm, maximum number of 20.33 leaves per plant, highest leaf area index of 582.56, maximum number of 8.00 cobs per plant, maximum number of 31.27 grains per cob, highest seed index of 41.33 and highest grains yield of 9.31 kg/plot when compared to all other sowing dates. The germination (r= 0.704), plant height (r= 0.641), number of leaves (r= 0.966), leaf area (r= 0.709), number of cobs per plant (r= 0.994), number of grains per cob (r= 0.698) and seed index (r= 0.968) are positively stimulated yield response in hybrid maize. Thus, sowing on 1st April has a paramount effect on the production of hybrid maize in Namsai conditions. Further study may be needed to investigate precise sowing dates of local maize in the Namsai region.

Optimization of inter-seasonal nitrogen allocation increases yield and resource-use efficiency in a water-limited wheat–maize cropping system in the North China Plain

Winter wheat–summer maize cropping system in the North China Plain often experiences drought-induced yield reduction in the wheat season and rainwater and nitrogen (N) fertilizer losses in the maize season. This study aimed to identify an optimal interseasonal water- and N-management strategy to alleviate these losses. Four ratios of allocation of 360 kg N ha−1 between the wheat and maize seasons under one-time presowing root-zone irrigation (W0) and additional jointing and anthesis irrigation (W2) in wheat and one irrigation after maize sowing were set as follows: N1 (120:240), N2 (180:180), N3 (240:120) and N4 (300:60). The results showed that under W0, the N3 treatment produced the highest annual yield, crop water productivity (WPC), and nitrogen partial factor productivity (PFPN). Increased N allocation in wheat under W0 improved wheat yield without affecting maize yield, as surplus nitrate after wheat harvest was retained in the topsoil layers and available for the subsequent maize. Under W2, annual yield was largest in the N2 treatment. The risk of nitrate leaching increased in W2 when N application rate in wheat exceeded that of the N2 treatment, especially in the wet year. Compared to W2N2, the W0N3 maintained 95.2% grain yield over two years. The WPC was higher in the W0 treatment than in the W2 treatment. Therefore, following limited total N rate, an appropriate fertilizer N transfer from maize to wheat season had the potential of a “triple win” for high annual yield, WPC and PFPN in a water-limited wheat–maize cropping system.

Ruminal degradation of maize starch is affected by sowing date

Context Delaying sowing date of maize allows producers to achieve stabilised yield. Delays in the sowing date generate changes in the grain structure, which may affect the ruminal degradability of the maize starch. Aims The objective of this study was to evaluate the effects of maize sowing date on ruminal starch degradability, and how it is related with grain physical characteristics and source:sink ratio during the grain-filling period. Methods To study the effects of maize sowing date on grain physical characteristics and on starch in situ effective degradability (ED; 6%/h passage rate from the rumen), eight treatments were defined on the basis of eight different sowing dates in Argentina of a commercial semi-dentate maize hybrid (Dekalb 7210 VT3P), as follows: Treatment 1 (13 October), Treatments 2, 3, and 4 (4, 17 and 26 November respectively), Treatments 5, 6 and 7 (3, 15 and 28 December, respectively) and Treatment 8 (5 January). For each sowing date, three plots of maize were sown in a complete randomised-block design and harvested at grain physiological maturity. Key results Starch ED of ground (2.0-mm) grains ranged from 631 to 801 g/kg and showed a ‘J’-shape response, being lower for the sowing dates from 17 November to 3 December and highest on the sowing date of 5 January. Grain density increased until the sowing date of 17 November, and then decreased. Grain vitreousness and hardness were initially not affected, but started to decline after the sowing date of 17 November. Grain test weight was not affected until the sowing date of 15 December, when it started to decline. The source:sink ratio during the grain-filling period decreased as the sowing date was delayed. Effective starch degradability was negatively correlated with the physical characteristics evaluated and the source:sink ratio. Conclusions Delaying sowing date affected the maize source:sink ratio during the grain-filling period; this was associated with changes in grain physical characteristics and with an increase in ruminal starch degradability. Implications Delaying sowing date increases dry matter (DM) and starch effective degradability, and therefore could affect cattle weight gain and feed conversion efficiency.

Effects of succession crops and soil tillage on suppressing the syndrome 'basses richesses' vector Pentastiridius leporinus in sugar beet.

Pentastiridius leporinus (Hemiptera: Cixiidae) is the most important vector of syndrome 'basses richesses' (SBR), a new disease that leads to severe economic losses in sugar beet. In this study, different soil tillage methods (ploughing and cultivator) and crops (winter wheat, spring wheat, maize and bare soil) following SBR-infested sugar beet were tested as potential management options in field trials. In the laboratory, the survival and development of first and third instar nymphs on wheat and maize was studied to further assess their suitability as host plants. In five out of seven field sites, reduced soil tillage had no effect on adult planthopper emergence compared to ploughing. In two sites, reduced tillage resulted in higher emergence rates. In nearly all field sites, up to 98.9% fewer emerging adults were detected in bare soil and maize, when compared to winter wheat. Under laboratory conditions, the lowest survival rate was found in first instar nymphs feeding on maize seedlings (4.2%), while 66.7% survived on wheat, over a period of 300 days. In contrast, 73.3% and 70% of third instar nymphs survived on wheat and maize over a period of 150 days. Soil tillage had little effect against Pentastiridius leporinus. Maize is a poor host for first instars but a suitable resource for third instar nymphs, the stage which encounters maize under field conditions. Hence, reductions in planthopper emergence in the field were likely caused by starvation due to the long host-free period between sugar beet harvest and the sowing of maize. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Agrobiological substantiation of growing Hungarian vetch in mixed crops

The production of high-protein feed stays an integral part of the development of feed production. The purpose of this study was to investigate the biological characteristics of Hungarian vetch when grown in agrophytocenoses using different types of winter cereals. Changes in the chemical composition of dry matter at different microstages of growth and development were studied, and the influence on the yield, nutrient content, and digestibility of plant material was determined depending on the stages of growth and development. The study was conducted using field, laboratory, laboratory-field, and statistical methods. It was found that to reach the full flowering phase, the sum of active temperatures should be 754°C, with precipitation of about 100 mm and daylight hours of 973 h. Observations of the growing season indicate the relationship between plants and the environment, which is important to consider when growing Hungarian vetch. Vetch plants reach a height of 100-104 cm in conditions of excessive moisture. The phytocoenotic balance of such mixtures, specifically vetch of the Orlan variety and winter triticale of the Bozhych and Bohodarske varieties, ensures sustainable productivity and nutritional value of plant material. The best harvesting time for high quality vetch is from the beginning to the middle of flowering, which ensures a crude protein content of 17-20% in dry matter. The effectiveness of mixed phytocoenoses has been confirmed by ecological tests of crop combination models in different soil and climatic zones of Ukraine, where yields of 36.2-51.8 t/ha of green mass and 7.1-11.5 t/ ha of dry matter were obtained over the years of use. The creation of a mixed crop allows producing high-quality plant material that is superior in energy and protein content to conventional vetch and oat mixtures. It was recommended to create such mixtures by sowing 2.5 mln/ha of cereal and 2.1 mln/ha of leguminous components after applying N45P45K45 to form a crop with high digestibility and nutrition. The system of mixed cropping of Hungarian vetch is promising for the production of silage and high-quality haylage in the face of climate change and as a precursor for post-cutting sowing of maize or sorghum crops

The Study of Various Regression Models Establishment to Identify Farmland Soil Moisture Content at Different Depths Using Unmanned Aerial Vehicle Multispectral Data: A Case in North China Plain

Soil moisture content is one of the most important soil indices for agriculture production. With the increasing food requirement and limited irrigation water sources, it is of great significance to accurately and quickly measure the soil moisture content for precision irrigation, especially in deficient agricultural areas, such as North China Plain. To achieve this goal, more attention was paid to the application of unmanned aerial vehicle multispectral reflectance technology. However, it was urgent to enhance the regression models between spectral data and soil realistic moisture content, and there were limited studies about the regression research on deep soil layers. Thus, the farmland of winter wheat–summer maize double cropping at Yongnian District, Hebei, North China, was selected as the study area. A six-band multispectral camera mounted on a low-altitude unmanned aerial vehicle (UAV) was used to obtain the field spectral reflectance with bands from 470~810 nm, and meanwhile, soil moisture content at different depths (10, 20, 30, 40, 50, and 60 cm) was measured after maize sowing. Unary linear regression (ULR), multivariate linear regression (MLR), ridge regression (RR), and an artificial neural network (ANN) were employed to establish regression models. The results demonstrated that the sensitive bands of spectral reflectance were 690 nm, 470 nm, and 810 nm. Those models all established significant regression at the depths of 0–20 cm and 40–60 cm, particularly at 10, 50, and 60 cm soil layers. However, for a depth of 20–40 cm, the prediction accuracy was generally lower. Among MLR, RR, and BP models, the MLR exhibited the highest identification accuracy, which was most recommended for the application. The findings of this study provide technical guidance and effective regression for the multispectral reflectance on the farmland of North China Plain, especially for deep soil layer moisture prediction.

The effects of sowing date on maize: Phenology, morphology, and yield formation in a hot subtropical monsoon region

Context or problemWith abundant thermal resources, there is a long-time span for potential maize sowing in the hot subtropical monsoon region. However, with different sowing dates, maize may be exposed to elevated temperatures at different growth stages. ObjectiveThis study aims to understand the impact of sowing date on maize growth and development and yield formation as temperatures increase. MethodsA 3-year field experiment was carried out in the typical subtropical monsoon region in China, with 11 sowing dates ranging from mid-March to late June with approximately 10-day intervals (named S1 to S11), and three main commercial varieties were included to validate the impact of sowing date. ResultsFollowing delayed sowing, maize plants were exposed to increased temperatures during the emergence (VE) to silking (R1) stages. Maize plants of the three varieties exhibited similar responses to delayed sowing dates in terms of growth, development, and yield performance. Vegetative growth was accelerated, while the anthesis-silking interval (ASI) and the vegetative-to-reproductive transition, that is, the interval of V12 (twelfth leaf) to R1 stages, were prolonged. The grain yield gradually decreased and reached a minimum at approximately S8-S10 (varied among varieties), which was in accordance with the decreased grain number. Further analyses revealed that the decreased grain number and yield were associated with a prolonged V12-R1 interval with delayed sowing. The duration of V12-R1 was significantly positively correlated with the maximum and minimum temperatures within a day, suggesting that the V12-R1 interval could be a parameter for evaluation of heat’s impact on yield formation. Grain weight decreased as the temperature of the R1-R6 stage rose before S8 but increased as the temperature dropped after S8. Inconsistently, biomass accumulation, leaf area, and plant and ear height first increased and then decreased before and after S3-S6, respectively. Conclusions and significanceDelayed sowing in hot subtropical monsoon regions exposes maize plants to elevated temperatures, leading to accelerated vegetative and reproductive growth but a prolonged vegetative-to-reproductive transition, and suppresses yield by reducing grain number and/or weight, resulting the yield decreased with the delayed sowing. By demonstrating the impacts of high temperature with different sowing dates on the phenology, morphology, and yield formation of maize, this study provides a basis for improving maize yield in practical production by optimizing the sowing date.

Agronomic and Economic Performance of Rain-Fed Maize (Zea mays L.) Production under Varying Sowing Dates and Multinutrient Fertilizer Levels in Shire Area, Northern Ethiopia

The present study was carried out to examine the combined effects of varying seed sowing and multinutrient fertilizer levels on maize yield in Shire area, Northern Ethiopia, in two consecutive cropping seasons (2018-2019). The experimental plots were designed in a split plot design with three replications. Sowing dates were determined based on the rainfall criteria of the AquaCrop model. Accordingly, the sowing date treatments were set as June 1, June 7, June 12, and June 16 for the 2018 cropping season, and the corresponding sowing dates for the 2019 cropping season were May 26, June 3, June 8, and June 12. The multinutrient fertilizer levels included 0, 100, 200, and 300 kg·ha−1. Agronomic related data were subjected to the analysis of variance, and partial budget analysis was applied for the economic performance evaluation. Maize yield was agronomically and economically influenced by sowing dates and multinutrient levels. Relative yield superiority that varies between 48.9 and 87.7% was found for each 100 kg·ha−1 multinutrient applied. On the other hand, with 4–6 days shifted towards earlier sowing resulted in an average yield increase by 4.9–66.9%. Application of 300 kg·ha−1 multinutrient for the early sown maize seems agronomically the superior treatment. However, from the economic analysis perspective, early maize sowing combined with the application of 200 kg·ha−1 multinutrient fertilizer was reported as the most profitable treatment. Late sowing of maize with the application of multinutrient fertilizer beyond 200 kg·ha−1 resulted in negative economic returns. The regression analysis results also indicated that maize grain yield tends to increase with the level of multinutrient fertilizer application (R2 = 0.841–0.864), whereas yield decreased with the delay in sowing dates (R2 = 0.927–0.995). Hence, this study concluded that the treatments with the best agronomic performance are not necessarily the best in terms of profitability.

Grain yield estimation of wheat-maize rotation cultivated land based on Sentinel-2 multi-spectral image: A case study in Caoxian County, Shandong, China

Establishing the remote sensing yield estimation model of wheat-maize rotation cultivated land can timely and accurately estimate the comprehensive grain yield. Taking the winter wheat-summer maize rotation cultivated land in Caoxian County, Shandong Province, as test object, using the Sentinel-2 images from 2018 to 2019, we compared the time-series feature classification based on QGIS platform and support vector machine algorithm to select the best method and extract sowing area of wheat-maize rotation cultivated land. Based on the correlation between wheat and maize vegetation index and the statistical yield, we screened the sensitive vegetation indices and their growth period, and obtained the vegetation index integral value of the sensitive spectral period by using the Newton-trapezoid integration method. We constructed the multiple linear regression and three machine learning (random forest, RF; neural network model, BP; support vector machine model, SVM) models based on the integral value combination to get the best and and optimized yield estimation model. The results showed that the accuracy rate of extracting wheat and maize sowing area based on time-series features using QGIS platform reached 94.6%, with the overall accuracy and Kappa coefficient were 5.9% and 0.12 higher than those of the support vector machine algorithm, respectively. The remote sensing yield estimation in sensitive spectral period was better than that in single growth period. The normalized differential vegetation index and ratio vegetation index integral group of wheat and enhanced vegetation index and structure intensify pigment vegetable index integral group of maize could more effectively aggregate spectral information. The optimal combination of vegetation index integral was difference, and the fitting accuracy of machine learning algorithm was higher than that of empirical statistical model. The optimal yield estimation model was the difference value group-random forest (DVG-RF) model of machine learning algorithm (R2=0.843, root mean square error=2.822 kg·hm-2), with a yield estimation accuracy of 93.4%. We explored the use of QGIS platform to extract the sowing area, and carried out a systematical case study on grain yield estimation method of wheat-maize rotation cultivated land. The established multi-vegetation index integral combination model was effective and feasible, which could improve accuracy and efficiency of yield estimation.