Maize Yield Formation Research Articles

Adaptation to priming drought at six-leaf stage relieves maize yield loss to individual and combined drought and heat stressors around flowering

The frequency and magnitude of drought and heat events are predicted to increase, exerting adverse effects on maize yield. Repeated stress events may lead to critical stage or process shifts in maize yield response, but few studies document such shifts. In this experiment, maize plants were exposed to drought at the six-leaf period (V6) to investigate the priming effects on maize yield formation under control (CK), drought stress (DS), heat stress (HS), and combined drought and heat stress (DHS) occurring around flowering (AF). The stressors was significantly reduced maize yield by 10.0%–41.4% compared with T1 (V6CK+AFCK), with the exception of the T5 (V6DS+AFCK) treatment. Fortunately, compared with T1 (V6CK+AFCK), T2 (V6CK+AFDS), T3 (V6CK+AFHS), and T4 (V6CK+AFDHS) treatments around flowering, exposure to drought at V6 improved yield by 6.4%, 11.1%, 2.6%, and 33.4%, respectively. The increased yield in stressors around flowering was attributed to the enhancement of kernel numbers (KNS) and kernel weight (KW). However, KNS and KW showed variable responses to treatments. Drought exposure at V6 relieved KNS loss without stressors around flowering, as the fertilized florets increased by 2.7%. The KNS loss in DS and DHS treatment around flowering was reversed via seed setting, increased by 6.0% and 7.4%, resulting from strengthened sugar-starch conversion. Furthermore, the reduced KW in HS and DHS treatment around flowering was improved due to increased starch synthesis ability during kernel filling. Consequently, drought priming at the V6 stage increased seed setting, sugar-starch conversion, and starch synthesis ability, improving KNS and KW, offering a method to relieve yield loss under stressors around flowering.

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.

A spectral decomposition method for estimating the leaf nitrogen status of maize by UAV-based hyperspectral imaging

Leaf nitrogen status plays a crucial role in characterizing maize nutrient activity, which ultimately affects both the photosynthetic efficiency and yield formation of maize. For this reason, hyperspectral imaging technology based on unmanned aerial vehicle (UAV) has emerged as a popular tool for estimating crop phenotypic traits. Canopy structure and leaf nutrition together determine the crop canopy spectrum. Efficient separation of the spectral information sensitive to the leaf nitrogen status from the canopy spectrum is considered of utmost importance for improving the estimation accuracy of maize leaf nitrogen status. Along these lines, the main goal of this work was to develop a canopy spectral decomposition method to reduce the interference of other traits on leaf nitrogen concentration (LNC) and leaf nitrogen density (LND) estimation using UAV-based hyperspectral images. First, the weights of the leaf nitrogen status, aboveground biomass (AGB), and leaf area index (LAI) contributing to the canopy spectrum were calculated by using the entropy weight method. Then, the sensitive bands of LNC and LND before and after spectral decomposition were selected by implementing the successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) algorithm. Finally, the reflectance of all bands and sensitive bands was compared to estimate maize LNC and LND using partial least squares regression (PLSR), Gaussian process regression (GPR), support vector regression (SVR), and random forest regression (RFR). These models were systematically tested using independent samples. From the acquired results, it was demonstrated that the correlation coefficient (r) between LNC and each band increased after spectral decomposition compared to the correlation before spectral decomposition. The r between the band reflectance in the near infrared region and LNC or LND after spectral decomposition was significantly higher than that before spectral decomposition. In addition, the sensitive bands of maize leaf nitrogen status after spectral decomposition were around 470 nm, 538 nm, 638 nm, 682 nm, 710 nm, 734 nm, and 830 nm. Regardless of using the reflectance of all bands or sensitive bands, the four estimation models of LNC and LND after spectral decomposition performed better than those before spectral decomposition. The estimation models of LNC and LND constructed by CARS-SVR can successfully reproduce the estimation accuracies of the models constructed by using all-bands-SVR, with R2 on the testing set of 0.68. Theresultshighlight that spectral decomposition is an effective method to significantly improve the estimation accuracy of maize leaf nitrogen status using UAV hyperspectral images, thus effectively reducing the interference of canopy structure traits (AGB and LAI).

An Increase in Solar Radiation in the Late Growth Period of Maize Alleviates the Adverse Effects of Climate Warming on the Growth and Development of Maize

Against the background of long-term climate change, quantifying the response of maize growth and development to climate change during critical growth stages will contribute to future decision-making in maize production. However, there have been few reports on the impact of climate change on maize dry matter accumulation and yield formation using long-term field trial data. In this study, field trial data from 13 agricultural meteorological stations in the Beijing–Tianjin–Hebei region from 1981 to 2017 were analyzed using partial correlation analysis and multiple regression models to investigate the effects of climate change on maize growth and yield. The results showed that the average temperature (Tavg) and accumulated effective precipitation (EP) during the maize growing season increased while the accumulated solar radiation (SRD) decreased from 1981 to 2017. During the seedling stage (GS1, VE-V8) and ear development stage (GS2, V8-R1), Tavg increased by 0.34 °C and 0.36 °C/decade, respectively, and EP increased by 1.83 mm and 3.35 mm/decade, respectively. The significant increase in Tavg during GS1 was the main reason for the inhibitory effect of climate change on maize growth, development, and biomass accumulation. However, the increase in SRD during the grain formation stage (GS3, R1–R3) and grain filling stage (GS4, R3–R6) was favorable for yield formation, increasing the grain number per ear (GN) and grain weight (GW) by 5.00% and 2.84%, respectively. SRD significantly increased after the silk stage, partially offsetting the adverse effects of temperature on maize yield formation, but the final result was a 0.18% and 0.94% reduction in maize plant dry weight (TDW) and grain yield (GY), respectively, due to the combined effects of the three climate factors. Spatially, climate change mainly had a negative impact on maize in the eastern and western parts of the central region of Beijing–Tianjin–Hebei, with a maximum GY reduction of up to 34.06%. The results of this study can provide a scientific basis for future decision-making in maize production against the background of climate change.

Effect Mechanism of Solar Radiation on Maize Yield Formation

Solar dimming due to global climate change is becoming increasingly more common in some agricultural areas. Such low-light stress inhibits maize ear number, kernel number per unit area (KN), and kernel weight (KW) as vital yield components. However, which yield component factors are most important for yield formation under low-light stress remains unknown. In this study at Qitai Farm in Xinjiang, China, in 2019 and 2020, we planted three maize (Zea mays L.) cultivars (Denghai 618 (DH618), Xianyu 335 (XY335), and Zhengdan 958 (ZD958)) at two densities (7.5 × 104 (D1) and 12 × 104 (D2) plants ha−1). We used four shading treatments (85% (S1), 70% (S2), and 50% (S3) natural light and no shading (CK)) from the three-leaf stage until maturity to create different light conditions. KN was the key factor that directly affected yield under low-light stress. For every 100 MJ m−2 decrease in photosynthetically active radiation (PAR), the KN decreased by 803.2 kernels per m2 . When the PAR was >674.3 MJ m−2 , KW tended to stabilize at 36.2 g/hundred kernels and the growth rate was 5.82 g/100 MJ m−2 per hundred kernels. DH618 and XY335 KNs were more sensitive to lowered solar radiation than ZD958. When density increased, DH618 required fewer light resources than the other cultivars to produce an equivalent amount of photosynthates for kernels. Therefore, in the face of climate change, particularly solar dimming, there is an urgent need to breed maize cultivars, such as DH618, with low-light stress tolerance and high grain yield.

Multifunctional Superabsorbent Polymer under Residue Incorporation Increased Maize Productivity through Improving Sandy Soil Properties

Superabsorbent polymer (SAP) is a new water-retaining and nutrient-holding material with the potential to improve soil properties and promote crop growth in arid and semiarid areas. This study investigated the effects of multifunctional SAP on the sandy soil properties and maize productivity in Yanghuang irrigated area of Ningxia where residue incorporation was a common agricultural practice, we tested multifunctional SAP at different doses of 0, 30, 60, 90, and 120 kg ha–1 under the residue incorporation to the field. The soil bulk density in the 0–0.40 m layer was significantly lower by 6.2–8.2% under SAP at 60–120 kg ha–1 compared with no SAP, but the total soil porosity was improved significantly by 8.5–11.2%, where the SAP at 90 and 120 kg ha–1 had the greatest effects. The applications of SAP at 60 and 90 kg ha–1 significantly improved soil organic matter, and availablePandKcontents in the 0–0.40 m soil layer. The soil water storage (0–1.0 m) under SAP at 60–120 kg ha–1 was significantly increased by 17.1–18.7% compared with no SAP throughout the whole maize growing season. The SAP at 60–90 kg ha–1 significantly promoted crop growth and maize yield formation, and increased grain yield, whereas the net income were the highest with applying SAP at 30–60 kg ha–1. In combination with the soil physicochemical property, crop productivity and economic benefit comprehensive analysis of this two-year study, we recommended that the application of multifunctional SAP at 30–60 kg ha–1 under residue incorporation significantly improved the sandy soil properties, as well as increasing maize growth, crop productivity, and obtain the higher net income for farmers in Yanghuang irrigation area of Ningxia, China.

Suitable fertilization depth can improve the water productivity and maize yield by regulating development of the root system

An undeveloped root system generally leads to low water utilization efficiency and decreases the yield in spring maize (Zea mays L.). Little is known about whether changing the fertilization depth can optimize the root distribution to improve the water productivity and maize yield. During 2019 and 2020, we conducted a field experiment with spring maize and applied the fertilizer at different soil depths of 0.05 m (D5), 0.15 m (D15), 0.25 m (D25), and 0.35 m (D35) to clarify the regulatory effects of the fertilization depth on the root distribution, water productivity at the biomass level (WPb), and maize yield formation. Compared with D5, D25 significantly increased the root length density of the vertical roots, inter-row roots, and within-row roots in the 0–1.0 m soil depth by 18%, 14%, and 24%, respectively, and the root surface area density increased by 39%, 17%, and 22%. Compared with D5, D25 significantly increased the soil water consumption by 28 mm during the maize jointing to silking stage and reduced the soil water content in the 0.4–1.4 m soil depth at the maize silking stage. D25 and D15 also significantly increased the root sap production rate and NO3–-N and NH4+-N concentrations in the root sap compared with D5 and D35 after the maize silking stage. The N uptake and nitrogen use efficiency under D25 were 17% and 39% higher, respectively, compared with D5. The water productivity at the grain yield and biomass level, biomass, and maize yield values under D25 were 23.5 kg ha–1 mm–1, 45.7 kg ha–1 mm–1, 24320 kg ha–1, and 12477 kg ha–1, respectively, which were 10%, 12%, 13%, and 14% higher compared with D5. The different fertilization depths explained 91%, 86%, and 66% of the variations in the maize yield, N uptake, and total evapotranspiration, respectively. Therefore, deep fertilization at a suitable soil depth regulated the distribution of the root system, which improved the capability of soil water and nitrogen utilization, and eventually increased the water productivity and maize yield. The most effective fertilizer depth was 0.25 m and it can be used as an effective water and fertilizer management strategy for the sustainable development of maize.

Quantitative Relationship Between Solar Radiation and Grain Filling Parameters of Maize.

A quantitative understanding of the factors driving changes in grain filling is essential for effective prioritization of increasing maize yield. Grain filling is a significant stage in maize yield formation. Solar radiation is the energy source for grain filling, which is the ultimate driving factor for final grain weight and grain filling capacity that determine maize yield. Here, we first confirmed the quantitative relationships between grain filling parameters and photosynthetically active radiation (PAR) by conducting field experiments using different shading and plant density conditions and cultivars in 2019 and 2020 in Xinjiang, China. The results showed that with every 100 MJ m−2 increase in PAR, the average grain filling rate (Gave), maximum grain-filling rate (Gmax), and the kernel weight at the time of maximum grain-filling rate (Wmax) increased by 0.073 mg kernel−1 day−1, 0.23 mg kernel−1 day−1, and 0.24 mg kernel−1, and the time of maximum grain-filling rate (Tmax) delayed by 0.91 day. Relative changes in PAR were significantly and positively correlated with relative changes in yield and Gave. With every 1% change in PAR, yield and Gave changed by 1.16 and 0.17%, respectively. From the perspective of grain filling capacity, DH618 was a more shade-resistant cultivar than XY335 and ZD958. It is urgent to breed maize cultivars with low light tolerance and high grain yield in the face of climate change, particularly the decrease in solar radiation.

Straw Mulching with Minimum Tillage Is the Best Method Suitable for Straw Application under Mechanical Grain Harvesting

Mechanical grain harvesting is a crop production development direction. However, the residue management methods suitable for mechanical grain harvesting have been not established. In order to study the effect of residue management modes on maize yield formation and explore the best residue management methods for mechanical grain harvesting, four crop field surveys were carried out in Southwest China. Crops were mechanically harvested, and the residues were shredded and returned to the field using various straw application methods including straw deep burial with plowing (SDBP), straw shallow burial with rotary tillage (SSBRT), and straw mulching with minimum tillage (SMMT). The first-season rape residues were returned to the field, and the second-season maize yield under SDBP and SSBRT was significantly higher than that under SMMT. However, with the increase in rounds of residue application, compared with SDBP and SSBRT, SMMT continuously increased the soil moisture content in the 0–30 cm soil layer at the early stage of maize growth, increased the soil alkaline-hydrolyzed nitrogen content in the 0–20 cm and 40–60 cm layers, and reduced the soil compaction under 40 cm layer, which were more conducive to the root system growth. Maize yield with the SMMT increased by 5.4% compared with that of the previous season, while the yields with SDBP and SSBRT decreased by 16.7% and 12.7%, respectively, compared with those of the previous season. In conclusion, it is recommended to employ the SMMT method during crop mechanical harvesting, which is of great significance to improve soil quality and increase maize grain yield.

Differential responses of maize yield to drought at vegetative and reproductive stages

Determining the effects of progressive drought (PD) on dry matter production, partitioning, and grain yield of maize will help in designing a suitable strategy for water management. Though influences of drought on maize growth and development have been investigated extensively, few of them focused on the effects of different duration and occurrence stage of PD on yield formation of maize. Six variations of PD, in the form of withholding irrigation for varying lengths of time from jointing or tasselling, were tested in the field, using a mobile rain shelter, in terms of their effects on aboveground biomass accumulation, partitioning, and grain yield in 2015–2016. The results showed that grain yield was significantly reduced by PD during either vegetative or reproductive stage, and the reduction in grain yield from reproductive PD (41.6–46.6%) was greater than that from vegetative PD (18.6–26.2%). The decrease in grain yield was largely caused by the decrease in kernels per ear (r<sup>2</sup> = 0.88, P < 0.001). This research implied that guaranteeing water supply for maize during reproductive stage is crucially important to avoid the reduction in kernels per ear and grain yield.

Effects of water deficit on the growth and yield formation of maize (Zea mays L.)

Maize (Zea mays L.) is the most important consuming cereal crop in the world after rice and wheat. This requires an understanding of various management practices as well as conditions that affect maize crop performance. Water deficit stress during crop production is one of the most serious threats to crop production in most parts of the world and drought stress or water deficit is an inevitable and recurring feature of global agriculture and it is against this background that field study of crops response to water deficit is very important to crop producer and researchers to maximize yield and improve crop production in this era of unpredicted climatic changes the world over.A pot experiment was carried out to determine the effects of water deficit on growth and yield formation of maize. Two maize cultivars were used Xundan20 and Zhongdan5485. Three levels of soil water content were used in two stages of water control levels at two stages of the maize plant development1. The JOINTING STAGE: A. CONTROL (CK) soil water content: from 70% to 80% of soil water holding capacity at the field, soil water content: from 55% to 65% of soil water holding capacity at the field, soil water content: from 40% to 50% of the Soil water holding capacity at the field.2. The BIG FLARE PERIOD: A. CONTROL (CK) soil water content: from 75% to 85% of soil water holding capacity at the field, soil water content: from 58% to 68% of soil water holding capacity at the field, soil water content: from 45% to 55% of the soil water holding capacity at the field.This research mainly studied the effects of water deficit on physiological, morphology and the agronomical characteristics of the maize plant at the different water stress levels.The importance of these results in this experiment will enable plant producers to focus and have a fair idea as to which stage of the maize plant’s development that much attention must be given to in terms of water supply.

Modelling the impact of heat stress on maize yield formation

The frequency and intensity of extreme high temperature events are expected to increase with climate change. Higher temperatures near anthesis have a large negative effect on maize (Zea mays, L.) grain yield. While crop growth models are commonly used to assess climate change impacts on maize and other crops, it is only recently that they have accounted for such heat stress effects, despite limited field data availability for model evaluation. There is also increasing awareness but limited testing of the importance of canopy temperature as compared to air temperature for heat stress impact simulations. In this study, four independent irrigated field trials with controlled heating imposed using polyethylene shelters were used to develop and evaluate a heat stress response function in the crop modeling framework SIMPLACE, in which the Lintul5 crop model was combined with a canopy temperature model. A dataset from Argentina with the temperate hybrid Nidera AX 842 MG (RM 119) was used to develop a yield reduction function based on accumulated hourly stress thermal time above a critical temperature of 34°C. A second dataset from Spain with a FAO 700 cultivar was used to evaluate the model with daily weather inputs in two sets of simulations. The first was used to calibrate SIMPLACE for conditions with no heat stress, and the second was used to evaluate SIMPLACE under conditions of heat stress using the reduction factor obtained with the Argentine dataset. Both sets of simulations were conducted twice; with the heat stress function alternatively driven with air and simulated canopy temperature. Grain yield simulated under heat stress conditions improved when canopy temperature was used instead of air temperature (RMSE equal to 175 and 309gm−2, respectively). For the irrigated and high radiative conditions, raising the critical threshold temperature for heat stress to 39°C improved yield simulation using air temperature (RMSE: 221gm−2) without the need to simulate canopy temperature (RMSE: 175gm−2). However, this approach of adjusting thresholds is only likely to work in environments where climatic variables and the level of soil water deficit are constant, such as irrigated conditions and are not appropriate for rainfed production conditions.

The impact of nitrogen fertilizer injection on kernel yield and yield formation of maize

In field experiments over three vegetation periods (2010–2012) we studied impact of the CULTAN (controlled uptake long term ammonium nutrition) method on yield and yield parameters of kernel maize. The field experiments were conducted at three sites with different soil-climatic conditions. CULTAN treatments were fertilized once with the total amount of nitrogen using an injection machine (at the canopy height of 20 cm) and compared to conventional fertilization with calcium ammonium nitrate application at pre-sowing preparations. In all treatments the amount of nitrogen was the same, 140 kg N/ha. In 2010 at Humpolec site, CULTAN urea ammonium nitrate + inhibitor of nitrification treatment gave by 20.5% higher number of ears compared to CULTAN urea ammonium nitrate treatment. In 2011 at Ivanovice all CULTAN treatments reached statistically significantly higher number of kernels per ear. The higher 1000 kernel weight at CULTAN treatments was observed in 2012 at the Ivanovice site; a statistically significant difference between conventional and CULTAN urea ammonium nitrate + inhibitor of nitrification treatment was observed. Fertilization of maize with nitrogen using the CULTAN method under the conditions of the Czech Republic provides the same yield certainty as the conventional surface application and the CULTAN method of fertilization increases the yield certainty at delayed sowing. Harvest index was statistically significantly influenced by year, fertilization treatment and site.

Effects of Plant Density, Nitrogen Application, and Water Stress on Yield Formation of Maize

It is important to promote adaptability of maize varieties to high-density,low nitrogen,and drought stresses so as to improve maize yield.Six maize varieties of Yuyu 22,Shaandan 902,Jingdan 28,Shaandan 8806,Xianyu 335,and Zhengdan 958 were planted under two kinds of densities(45 000 and 75 000 plants ha-1),pure nitrogen levels(112.5 and 337.5 kg ha-1),and water treatments(controlling water at prophase and normal irrigation) in fields to elucidate effects of stresses(high density,low nitrogen,and drought) on yield formation of maize varieties.Main physiological parameters of source-sink traits and grain yield were measured.The results showed that differences of grain yield were little among maize varieties under less environmental pressure(low density,high nitrogen,and normal irrigation),while these were significant under stress(high density,low nitrogen,and drought).Changes of source traits(LAI,Pn of ear leaves and source capacity),sink traits(sink capacity of population),harmonious source-sink traits(sink-source ratio,grain filling rate and harvest index),dry matter accumulation at maturity and dry matter accumulation from silking stage to maturity showed the same rules as grain yield.There were significantly positive correlations between grain yield and LAI,source capacity,dry matter accumulation at maturity,dry matter accumulation from silking stage to maturity,sink capacity of population and harvest index.To improve maize yield,we should strengthen artificial selection for adapting to natural selection,improve source-sink trait of maize population under stress,enhance leaf photosynthetic efficiency from silking stage to maturity,strengthen source and promote sink,and improve production capacity and adaptability under stresses.

Effect of sowing date, nitrogen fertilization and plant density on the dynamics of dry matter accumulation and yield formation of maize (Zea maysL.) hybrids

Effect of sowing date, nitrogen fertilization and plant density on the dynamics of dry matter accumulation and yield formation of maize (<i>Zea mays</i>L.) hybrids

Fertilisation and irrigation effects on maize (Zea mays L.) grain production

Research has shown that the two most important factors in maize yield formation in Hungary are water and nutrient supply. Utilising eleven years of data from a long-term maize field experiment at the Debrecen University Latokep Experimental Station, the interaction between irrigation and nutrient supply of maize was analysed. Calculations were made to determine the schedule of irrigation based on soil moisture, precipitation, and transpiration. The experiment had three levels of nutrient supply: plots without fertilisation (Tl); fertilised plots at rates of 120 kg ha−1 N, 90 kg ha−1 P and 106 kg ha−1 K (T2); and fertilised plots of 240 kg ha−1 N, 180 kg ha−1 P and 216 kg ha−1 K (T3). Statistical methods of stability and relative stability analysis were used to evaluate the effects of irrigation and fertilisation on grain yield. Nutrition treatments behaved differently in non-irrigated and irrigated plots. Without irrigation, if the environment was unfavourable the control yield was greater and more stable than fertilised treatments. In high yielding environments, fertilised treatments produced similar amounts grain. In the case of irrigation, the yield of fertilised plots exceeded the yield of the control, irrespective of the environment. In irrigated plots, fertilised treatments reacted similarly, but the most stable treatment was treatment T2.