Improve Maize Yield Research Articles

Impacts of High Temperature and Vapor Pressure Deficit on the Maize Opened Spikelet Ratio and Pollen Viability

High temperatures (HTs) and high vapor pressure deficits (VPDs) have significant impacts on maize yields, partly due to the high sensitivity of maize tassels. However, there are few studies quantifying the impacts of HTs and VPDs on maize tassel performance under changing environments. Therefore, we carried out a two-year field experiment that included 20 inbred lines and four sowing dates. Compared with the first sowing date, the seed set in the second sowing date decreased by ~80% in both years. The opened spikelet ratio (OSR) and pollen viability (PV) were the key determinants of seed set, and their respective correlation coefficients with seed set were 0.58 and 0.90. The OSR and PV decreased by ~20% and ~50%, respectively, under high-temperature stress. When Tmax exceeded 32.5 °C or the VPD exceeded 0.91 KPa, PV began to decline; when Tmax exceeded 33.8 °C or VPD exceeded 1.10 KPa, the OSR began to decline. The OSR was more dependent on genotypic background than PV (28.4% vs. 19.7%). The maize tassel water content was significantly correlated with the OSR and PV. Based on the OSR and PV values, the 20 genotypes were divided into three different groups, namely the high H, middle M, and low L groups. The H group, on average, had the highest kernel number per ear and seed set, followed by the M and L groups. The average seed sets of the H, M, and L genotypes under the second sowing date were 17.4%, 10.9%, and 0%, respectively, in 2019 and 13.8%, 7.9%, and 0.6%, respectively, in 2020. The present results indicate that selecting maize varieties with a high OSR is an effective approach for improving maize yield under heat stress.

Improving maize yield and drought tolerance in field conditions through activated biochar application

Amidst depleting water resources, rising crop water needs, changing climates, and soil fertility decline from inorganic modifications of soil, the need for sustainable agricultural solutions has been more pressing. The experimental work aimed to inspect the potential of organically activated biochar in improving soil physicochemical and nutrient status as well as improving biochemical and physiological processes, and optimizing yield-related attributes under optimal and deficit irrigation conditions. Biochar enhances soil structure, water retention, and nutrient availability, while improving plant nutrient uptake and drought resilience. The field experiment with maize crop was conducted in Hardaas Pur (32°38.37’N, 74°9.00’E), Gujrat, Pakistan. The experiment involved the use of DK-9108, DK-6321, and Sarhaab maize hybrid seeds, with five moisture levels of evapotranspiration (100% ETC, 80% ETC, 70% ETC, 60% ETC, and 50% ETC) maintained throughout the crop seasons. Furthermore, activated biochar was applied at three levels: 0 tons/ha (no biochar), 5 tons per hectare, and 10 tons per hectare. The study’s findings revealed significant improvements in soil organic matter, bulk density, nutrient profile and total porosity with biochar supplementation in soil. Maize plants grown under lower levels of ETC in biochar supplemented soil had enhanced membrane stability index (1.6 times higher) increased protein content (1.4 times higher), reduced malondialdehyde levels (0.7 times lower), improved antioxidant enzyme activity (1.3 times more SOD and POD activity, and 1.2 times more CAT activity), improved relative growth (1.05 times more) and enhanced yield parameters (26% more grain and stover yield, 16% more 1000-seed weight, 29% more total seed weight, 33% more apparent water productivity) than control. Additionally, among the two biochar application levels tested, the 5 tons/ha dose demonstrated superior efficiency compared to the 10 tons/ha biochar dose.

Cow Dung Liquid Mulch Improves Maize Yields: Beneficial Microorganisms Are Enriched and Environmental Risks Are Reduced and Nutrient Cycling Is Promoted

Cow dung liquid mulch (CDLM), which uses cow dung as a raw material, has a good degradability and is a potential alternative to traditional plastic agricultural mulch, but there is a lack of research on the effects of CDLM on rhizosphere soil physicochemical properties, rhizosphere soil microbial functions, and crop yields. In this study, the link between maize yield, environmental factors, and functional genes as well as the responses of microbial community functions to CDLM and polyethylene mulch (PE) were studied using metagenomic sequencing. Functional annotation was also performed on clusters of orthologous groups of proteins, the Kyoto Encyclopedia of Genes and Genomes, and carbohydrate-active enzyme sequencing data. The results showed that CDLM significantly increased maize yield by 30.9% compared to CK while maintaining lower soil microplastic levels. CDLM promotes the enrichment of beneficial microorganisms such as Mycolicibacterium and Pseudomonas. The relative abundance of functional genes related to microbial metabolism, soil element cycling pathways, and organic matter degradation was significantly higher in CDLM than in CK. Microbial functional genes were positively correlated with maize yield and environmental factors such as soil nutrients. These results suggested that CDLM can improve maize yield by enriching beneficial microorganisms, reducing rhizosphere soil environmental risks, and enhancing rhizosphere soil microbial function. Rhizosphere soil nutrients and microbial functional genes together mediated the positive response of maize yield to CDLM. This study can provide a scientific basis and data support for the safe use of mulch in the future.

Comparative Study of the Efficacy of Two Biological Insecticides (Azadirachta indica and Bacillus thuringiensis) and a Chemical insecticide (Diflubenzuron WP) against Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) in Maize Crop, Western Bur

Aims: This study aimed at comparing the biological efficacy of Diflubenzuron WP, a chemical insecticide, and two biopesticides, one based on neem oil (Azadirachta indica) and an entomopathogen (Bacillus thuringiensis) against the fall armyworm on maize. Place and Duration of Study: The work was carried out on the irrigated scheme of Bama, western Burkina Faso during the 2022 and 2023 wet seasons. Methodology: The experimental design was a Fisher block with 4 treatments: T0: untreated or control; T1: Bacillus thuringiensis; T2: neem oil; T3: Diflubenzuron WP, in 4 replications. Entomological observations focused on the score and severity of attacks, as well as the pest's infestations rate. Results: The results showed that the different insecticides tested over the two wet seasons of 2022 and 2023 induced better control of S. frugiperda populations, with larval density being kept lower with the treatment of Diflubenzuron WP (4.25±1.2%), neem oil (14.28±1.6%) and Bacillus thuringiensis (24.5±3.2%). The insect damage severity rates and scores of damaged ears were also low for the three treatments respectively (1.09±0.2, 0.9±0.26 and 0.27±0.71) over the two cropping seasons. Diflubenzuron WP insecticide treatment not only reduced pest pressure, but also significantly improved maize yield. No surprisingly the highest yield (5.14 t/ha) was recorded with Diflubenzuron WP, followed by neem oil (4.62kg/ha) and finally Bacillus thuringiensis (3.92kg/ha). Conclusion: Further studies are needed to determine the optimal doses of neem oil and Bt for the control of Fall Armyworm. Neem oil can be considered as a good alternative to a chemical insecticide like Diflubenzuron WP.

Agronomic potential of maize stover biochar under cowpea–maize sequential cropping in Northern Uganda

Biochar is a nature-based solution for sustainable agriculture but its potential adoption in some parts of sub-Saharan Africa is still minimal. In this study, we evaluated the agronomic potential of maize stover biochar in cowpea-maize sequential cropping in Uganda under field conditions. The treatments included; the common farmer practice of no inorganic fertilizer and no biochar (CTR), inorganic fertilizer (F), 10 t ha−1 biochar (B10), 40 t ha−1 biochar (B40), 10 t ha−1 biochar + inorganic Fertilizer (FB10), and 40 t ha−1 biochar + inorganic Fertilizer (FB40), arranged in a randomized complete block design (RCBD) with three replications. The results showed that cowpea seed yield was not significantly affected by biochar and fertilizer application but the haulm yield was significantly improved only in FB40 treatment. Maize grain and stover yield was significantly improved only in the FB40 treatment but biochar showed a high potential to also improve yield even without inorganic fertilizer. The potential for biochar to improve maize yield either in the presence or absence of fertilizers could be attributed to the residual soil fertility from cowpeas. In both seasons, biochar significantly improved soil pH, EC, SOC, total N, available P, exchangeable K and Ca, irrespective of fertilizer application. However, exchangeable Mg did not significantly vary among the treatments. This study further revealed that in cowpea-maize rotation, optimum yield could also be possible with sole biochar application. Therefore, instead of burning the maize stovers after harvest, farmers should convert the residues into biochar and return it to the soil so as to achieve sustainable food systems.Graphical

Mixture Effect of Rock Phosphate and Triple Superphosphate on Maize Yield in Acid Soils of Côte d'Ivoire

Aims: Determine the optimum rock phosphate (RP) / Triple superphosphate (TSP) ratio for improved maize yield Study Design: The experimental design was of random blocks with 3 replications. Place and Duration of Study: The study was carried out in central Cote d'Ivoire, in a savannah area over 3 consecutive years 2019, 2020 and 2021. Methodology: Eight treatments were tested: control T0, T0r (100 Kg urea ha-1 + 200 Kg NPK ha-1), T1 (300 Kg RP ha-1), T2 (270Kg RP ha-1 + 19,6 Kg TSP ha-1), T3 (240 Kg RP + 39,2 Kg TSP ha-1 ), T4 (180 Kg RP ha-1 + 78,4 Kg TSP ha-1), T5 (60 Kg RP ha-1 + 156,8 Kg TSP ha-1 ), T6 (196 Kg TSP ha-1 ). For maintenance, 200 Kg NPK ha-1 and 100 Kg urea ha-1 were added to all treatments except control. After harvest, yields were calculated, pH levels were measured at the beginning, after three months and at the end of the trial. Results: the effect of the RP/TSP combination was effective in the second year. Ratio T3 obtained the best yield (5.71 t ha-1) and was more efficient than the treatment used for maize extension in Côte d'Ivoire (T0r). At the same time, the soil pH has become neutral, contributing to an improvement in soil fertility due to the gradual bioavailability of phosphorus from the solubilized phosphate rock. Conclusion: Mixing RP and TSP in proportions of T3 (240 Kg RP + 39,2 Kg TSP ha-1) is effective in improving maize yields.

Straw incorporation and nitrogen fertilization regulate soil quality, enzyme activities and maize crop productivity in dual maize cropping system

BackgroundStraw incorporation serves as an effective strategy to enhance soil fertility and soil microbial biomass carbon (SMBC), which in turn improves maize yield and agricultural sustainability. However, our understanding of nitrogen (N) fertilization and straw incorporation into soil microenvironment is still evolving. This study explored the impact of six N fertilization rates (N0, N100, N150, N200, N250, and N300) with and without straw incorporation on soil fertility, SMBC, enzyme activities, and maize yield.ResultsResults showed that both straw management and N fertilization significantly affected soil organic carbon (SOC), total N, SMBC, soil enzyme activities, and maize yield. Specifically, the N250 treatment combined with straw incorporation significantly increased SOC, total N, and SMBC compared to lower fertilization rates. Additionally, enzyme activities such as urease, cellulase, sucrose, catalase, and acid phosphatase reached their peak during the V6 growth stage in the N200 treatment under for both straw management conditions. Compared to N250 and N300 treatments of traditional planting, the N200 treatment with residue incorporation significantly increased yield by 8.30 and 4.22%, respectively. All measured parameters, except for cellulase activity, were significantly higher in spring than in the autumn across both study years, with notable increases observed in 2021.ConclusionsThese findings suggest that optimal levels of SOC, soil total N (STN), and SMBC, along with increased soil enzyme activities, is crucial for sustaining soil fertility and enhancing maize grain yield under straw incorporation and N200 treatments.

Combining No-Tillage with Hairy Vetch Return Improves Production and Nitrogen Utilization in Silage Maize.

The combination of no-till farming and green manure is key to nourishing the soil and increasing crop yields. However, it remains unclear how to enhance the efficiency of green manure under no-till conditions. We conducted a two-factor field trial of silage maize rotated with hairy vetch to test the effects of tillage methods and returning. Factor 1 is the type of tillage, which is divided into conventional ploughing and no-tillage; factor 2 is the different ways of returning hairy vetch as green manure, which were also compared: no return (NM), stubble return (H), mulching (HM), turnover (HR, for CT only), and live coverage (LM, for NT only). Our findings indicate that different methods of returning hairy vetch to the field will improve maize yield and quality. The best results were obtained in CT and NT in HM and LM, respectively. Specifically, HM resulted in the highest dry matter quality and yield, with improvements of 35.4% and 31.9% over NM under CT, respectively. It also demonstrated the best economic and net energy performance. However, other treatments had no significant effect on the beneficial utilization and return of nutrients. The LM improved yields under NT by boosting soil enzyme activity, promoting nitrogen transformation and accumulation, and increasing nitrogen use efficiency for better kernel development. Overall, NTLM is best at utilizing and distributing soil nutrients and increasing silage maize yield. This finding supports the eco-efficient cultivation approach in silage maize production in the region.

Sub-surface drip-fertigation and legume residue improved maize yield and nitrogen use

Sub-surface drip-fertigation and legume residue improved maize yield and nitrogen use

Climate Change Impact on Rain-Fed Maize Yield Cultivated with Small-Scale Landowners in Wolaita Zone, Ethiopia

Ethiopia is a country that heavily relies on rainfall-aided cultivation which is carried out by small-scale landowners, leaving it very vulnerable to climate change and fluctuation. The primary goal of this research is to investigate how climate change affects maize yield in Wolaita zone of Ethiopia. The authors were employed a linear regression method to evaluate the relationship between climate parameters and maize yield. Sen's slope magnitude estimator and the Mann-Kendal trend test were used to assess the significance of climate change. The outcome demonstrated that the temperature extreme indices of warm days and the length of warm days were considerably higher by 37.5% and 3.7% of days per year, however, cold days and cold spells were significantly decreased. Over the 1981-2021 periods, there was a significant upward pattern in TXx and TNn at an average of 0.033°C and 0.034°C. There was a considerable decline of 2.3% in the simple daily precipitation intensity index and 33% decreased in extremely heavy precipitation, respectively. The correlation analysis's findings indicated that growing period precipitation and maize outputs were positively correlated, but negatively correlated with maximum and minimum temperatures. Extreme temperature and precipitation were more explained a maize yield than average climate patterns. 12.4%, 14.76%, 13.08%, and 7.95% of maize output variability was attributed by the growing season mean climate conditions, which include precipitation, mean, minimum, and maximum temperature. The variability of maize output was explained by combined impact of precipitation and temperature extremes were 67.7% and 45.0%, respectively. Therefore, livelihood diversification and relevant policy formulation are suggested to adapt inevitable climate change by implementing irrigation and resistant varieties to improve maize yield production.

Improving maize yield estimation by assimilating UAV-based LAI into WOFOST model

ContextCrop growth models were widely applied for simulating the dynamic growth of crops at multi-scales. The data assimilation by integrating the remote sensing data retrieved crop parameters and crop models have showed great potentials for describing the crop growth and assessing the agricultural yields. ObjectiveThe purpose of this study was to integrates sequential observations of crop phenotyping traits from Unmanned Aerial Vehicles (UAV) remote sensing into World Food Studies (WOFOST) model to improve the simulation of crop growth processes. MethodsTwo years of Leaf Area Index (LAI) of summer maize retrieved from Unmanned Aerial Vehicles (UAV)-RGB images was assimilated into the WOFOST using the Ensemble Kalman Filter (EnKF). The sensitive crop parameters of WOFOST were firstly identified using the Extended Fourier Amplitude Sensitivity Test (EFAST) global sensitivity analysis approach, and then the parameters were adjusted and confirmed using the SUBPLEX optimization algorithm. The LAI data was assimilated into WOFOST model using EnKF by minimizing the differences between the UAV-retrieved LAI and crop-simulated LAI. Results indicated assimilating LAI into WOFOST model significantly improved the accuracy of maize yield prediction. ResultsCompared with non-assimilation, data assimilation reduced the Root Mean Square Error (RMSE) from 413 to 132 kg/ha for 2020, and from 392 to 215 kg/ha for 2021, respectively. Through the effects of different ensemble size and different time-point for data assimilation, it was obtained that the accuracy of yield prediction achieved the highest when ensemble size was 100 at reproductive growth stage. ConclusionsIntegrating UAV-based crop traits into WOFOST model using data assimilation (EnKF) could effectively improve the maize yield accuracy.

The additive function of YIGE2 and YIGE1 in regulating maize ear length.

Ear length (EL) is a key trait that greatly contributes to yield in maize. Although dozens of EL quantitative trait loci have been mapped, very few causal genes have been cloned, and the molecular mechanisms remain largely unknown. Our previous study showed that YIGE1 is involved in sugar and auxin pathways to regulate ear inflorescence meristem (IM) development and thus affects EL in maize. Here, we reveal that YIGE2, the paralog of YIGE1, regulates maize ear development and EL through auxin pathway. Knockout of YIGE2 causes a significant decrease of auxin level, IM length, floret number, EL, and grain yield. yige1 yige2 double mutants had even shorter IM and ears implying that these two genes redundantly regulate IM development and EL. The genes controlling auxin levels are differential expressed in yige1 yige2 double mutants, leading to lower auxin level. These results elucidated the critical role of YIGE2 and the redundancy between YIGE2 and YIGE1 in maize ear development, providing a new genetic resource for maize yield improvement.

Transcription factor ZmDof22 enhances drought tolerance by regulating stomatal movement and antioxidant enzymes activities in maize (Zea mays L.).

The Dof22 gene encoding a deoxyribonucleic acid binding with one finger in maize, which is associated with its drought tolerance. The identification of drought stress regulatory genes is essential for the genetic improvement of maize yield. Deoxyribonucleic acid binding with one finger (Dof), a plant-specific transcription factor family, is involved in signal transduction, morphogenesis, and environmental stress responses. In present study, by weighted correlation network analysis (WGCNA) and gene co-expression network analysis, 15 putative Dof genes were identified from maize that respond to drought and rewatering. A real-time fluorescence quantitative PCR showed that these 15 genes were strongly induced by drought and ABA treatment, and among them ZmDof22 was highly induced by drought and ABA treatment. Its expression level increased by nearly 200 times after drought stress and more than 50 times after ABA treatment. After the normal conditions were restored, the expression levels were nearly 100 times and 40 times of those before treatment, respectively. The Gal4-LexA/UAS system and transcriptional activation analysis indicate that ZmDof22 is a transcriptional activator regulating drought tolerance and recovery ability in maize. Further, overexpressed transgenic and mutant plants of ZmDof22 by CRISPR/Cas9, indicates that the ZmDof22, improves maize drought tolerance by promoting stomatal closure, reduces water loss, and enhances antioxidant enzyme activity by participating in the ABA pathways. Taken together, our findings laid a foundation for further functional studies of the ZmDof gene family and provided insights into the role of the ZmDof22 regulatory network in controlling drought tolerance and recovery ability of maize.

Moderately reducing N input to mitigate heat stress in maize

In a warming climate, high temperature stress greatly threatens crop yields. Maize is critical to food security, but frequent extreme heat events coincide temporally and spatially with the period of kernel number determination (e.g., flowering stage), greatly limiting maize yields. In this context, how to increase or at least maintain maize yield has become more important. Nitrogen fertilizer (N) is widely used to improve maize yields, but its effect in heat stress is unclear. For this, we collected 1536 pairs of comparisons from 113 studies concerning N conducted in the past 20 years over China. We classified the data into two groups – without high temperature stress (NHT) and with high temperature stress during the critical period for maize kernel number determination (HT) – based on the national meteorological data. We comprehensively evaluated N effects on grain yield under HT and NHT using meta-analysis. The effect of N on maize yield became significantly smaller in HT than that in NHT. In NHT, soil characteristics, crop management practices, and climatic conditions all significantly affected N effects on maize yield, but in HT, only a few factors such as soil organic matter and mean annual precipitation significantly affected N effects. Hence, it is difficult to improve N effect by improving soil characteristics and crop management when meeting with high temperature stress during flowering. On average, N effect increased with increased N input, but there were respective N input thresholds in NHT and HT, beyond which N effects on maize yield remained stable. According to the thresholds, it is speculated that moderately reducing N input (~20 %) likely increased high temperature tolerance of maize during flowering. These findings have important implications for the optimization of N management under a warming climate.

Intercropping improves maize yield and nitrogen uptake by regulating nitrogen transformation and functional microbial abundance in rhizosphere soil

Intercropping-driven changes in nitrogen (N)-acquiring microbial genomes and functional expression regulate soil N availability and plant N uptake. However, present data seem to be limited to a specific community, obscuring the viewpoint of entire N-acquiring microbiomes and functions. Taking maize intercropped with legumes (peanut and soybean) and non-legumes (gingelly and sweet potato) as models, we studied the effects of intercropping on N transformations and N-acquiring microbiomes in rhizosphere soil across four maize growth stages. Meanwhile, we compiled promising strategies such as random forest analysis and structural equation model for the exploitation of the associations between microbe-driven N dynamics and soil-plant N trade-offs and maize productivity. Compared with monoculture, maize intercropping significantly increased the denitrification rate of rhizosphere soils across four maize growth stages, net N mineralization in the elongation and flowering stages, and the nitrification rate in the seedling and mature stages. The abundance of most N-acquiring microbial populations was influenced significantly by intercropping patterns and maize growth stages. Soil available N components (NH4+-N, NO3−-N, and dissolved organic N content) showed a highly direct effect on plant N uptake, which mainly mediated by N transformations (denitrification rate) and N-acquiring populations (amoB, nirK3, and hzsB genes). Overall, the adaptation of N-acquiring microbiomes to changing rhizosphere micro-environments caused by intercropping patterns and maize development could promote soil N transformations and dynamics to meet demand of maize for N nutrient. This would offer another unique perspective to manage the benefits of the highly N-effective and production-effective intercropping ecosystems.

Photosynthetic capacity and assimilate transport of the lower canopy influence maize yield under high planting density.

Photosynthesis is a major trait of interest for the development of high-yield crop plants. However, little is known about the effects of high-density planting on photosynthetic responses at the whole-canopy level. Using the high-yielding maize (Zea mays L.) cultivars "LY66," "MC670," and "JK968," we conducted a 2-yr field experiment to assess ear development in addition to leaf characteristics and photosynthetic parameters in each canopy layer at 4 planting densities. Increased planting density promoted high grain yield and population-scale biomass accumulation despite reduced per-plant productivity. MC670 had the strongest adaptability to high-density planting conditions. A physiological analysis showed that increased planting density primarily led to decreases in the single-leaf area above the ear for LY66 and MC670 and below the ear for JK968. Furthermore, high planting density decreased chlorophyll content and the photosynthetic rate due to decreased canopy transmission, leading to severe decreases in single-plant biomass accumulation in the lower canopy. Moreover, increased planting density improved presilking biomass transfer, especially in the lower canopy. The yield showed significant positive relationships with photosynthesis and biomass in the lower canopy, demonstrating the important contributions of these leaves to grain yield under dense planting conditions. Increased planting density led to retarded ear development as a consequence of reduced glucose and fructose contents in the ears, indicating reductions in sugar transport that were associated with limited sink organ development, reduced kernel number, and yield loss. Overall, these findings highlighted the photosynthetic capacities of the lower canopy as promising targets for improving maize yield under dense planting conditions.

A Method to Estimate Climate Drivers of Maize Yield Predictability Leveraging Genetic-by-Environment Interactions in the US and Canada

Throughout history, the pursuit of diagnosing and predicting crop yields has evidenced genetics, environment, and management practices intertwined in achieving food security. However, the sensitivity of crop phenotypes and genetic responses to climate still hampers the identification of the underlying abilities of plants to adapt to climate change. We hypothesize that the PiAnosi and WagNer (PAWN) global sensitivity analysis (GSA) coupled with a genetic by environment (GxE) model built of environmental covariance and genetic markers structures, can evidence the contributions of climate on the predictability of maize yields in the U.S. and Ontario, Canada. The GSA-GxE framework estimates the relative contribution of climate variables to improving maize yield predictions. Using an enhanced version of the Genomes to Fields initiative database, the GSA-GxE framework shows that the spatially aggregated sensitivity of maize yield predictability is attributed to solar radiation, followed by temperature, rainfall, and relative humidity. In one-third of the individually assessed locations, rainfall was the primary responsible for maize yield predictability. Also, a consistent pattern of top sensitivities (Relative Humidity, Solar Radiation, and Temperature) as the main or the second most relevant drivers of maize yield predictability shed some light on the drivers of genetic improvement in response to climate change.

Response of nutrient accumulation, remobilization and yield to combined application of nitrogen and potassium in waxy maize

Unbalanced fertilizers supply with highly intensity and excessive nitrogen (N) and less potassium (K), lead to the decrease of soil fertility year by year. Balanced fertilization is one of the most effective measures to reduce fertilizer use while improving maize yield and efficiency. Two N levels (180 and 225 kg N ha−1, abbreviated N12 and N15) and four K treatments (0, 75, 150, and 75+75 kg K2O ha−1, abbreviated K0, K5, K10, and K5+5) were set to study the effects of combined application of N and K on the biomass and nutrient accumulation and remobilization characteristics in waxy maize. The results demonstrated that grain yield increased when higher amounts of K were applied at constant N levels, showing an average increase of 1,254.8 kg ha−1 (2020) and 727.3 kg ha−1 (2021) compared with K0. Under same N and K application, K5+5 increased grain yield by increasing kernel weight. Under K5+5 treatment, the biomass and nutrient accumulation had no significant difference between N12 and N15. Compared with K10, K5+5 not only enhanced the average remobilization amount (RBA) of biomass, but also increased RBA of N, phosphorus (P) and K. In addition, the average remobilization efficiency (RBE) of biomass, N, P and K in K5+5 were increased 3.3, 4.6, 10.6 and 4.2%, respectively. Furthermore, topdressing K improved the apparent contribution to grain (AC) of biomass, N, P and K, which promoted more nutrient to grains, and significantly increased nutrient harvest index. Considering yield and fertilizer use efficiency, we recommend optimized K application (basal and topdressing 75 kg ha−1) and moderately reduced N application (from 225 to 180 kg ha−1) in the production of spring-sown waxy maize in southern China.

Effect of lime, blended fertilizer and vermicompost on maize (Zea mays) yield in Assosa district, north-western Ethiopia

Application of organic and mineral fertilizers improves crop productivity and availability of plant nutrients. Further investigation into their integral application is crucial to obtaining optimum crop productivity. A field experiment was conducted during 2020–21 and 2021–22 at experimental field station in Benshangul Gumuz, Assosa University, Assosa, Ethiopia to investigate the response of maize (Zea mays L.) yield to lime, blended NPSZnB fertilizer and vermicompost. Two lime levels, three vermicompost levels, and three blended fertilizer levels were factorially combined and laid out in a randomized complete block design (RCBD). The integral application of organic fertilizer with blended fertilizer with lime significantly affected the agronomic parameters. Grain yield, number of grains per cob, 1000-seed weights, plant height, and days to 50% tasseling were parameters most affected by the amendments. Integral application of 50% of the recommended rate of blended fertilizer and vermicompost with lime improved maize yield by 53%, while the application of NPSZnB and vermicompost individually improved maize yield by 34% and 22% over the control treatment. One tonne of vermicompost and lime could substitute 38 kg and 23 kg of blended fertilizer, respectively. In conclusion, the integrated application of NPSZnB and vermicompost with the recommended amount of lime was the best soil fertility management option. In terms of grain yield and net benefit, 4 t/ha lime, 2.5 t/ha vermicompost and 100 kg/ha blended fertilizers were recommended for optimum maize production in the Assosa area and similar agroecologies.

Differences in dry matter production and grain yield of maize (Zea mays L.) cultivars with contrasting nitrogen efficiency

ABSTRACT We aimed to investigate the differences in dry matter accumulation (DMA), distribution, remobilisation, and yield of maize cultivars with contrasting nitrogen efficiency responses to nitrogen application rates. Nitrogen fertiliser increased DMA, crop growth rate (CGR), redistribution of pre-silking dry matter, and accumulation of post-silking dry matter while reducing the root/shoot biomass ratio to substantially increase biomass yield and final maize grain yield. Higher final theoretical biomass yield, maximum increasing rate (MIR), and average increasing rate, later days to MIR, longer duration of rapid growth period, higher ratio of vegetative organs, and rational dry matter distribution aboveground and belowground contribute to higher DMA and CGR in the later growth stage, and higher assimilated dry matter into grain and biomass yield to finally obtain higher grain yield for N-efficient maize cultivar. The N-efficient cultivar had obvious advantages on grain yield compared with N-inefficient cultivar caused by higher dry matter average increasing rate and biomass and kernels per ear, while the advantages increased first, then decreased with higher N rates, and the highest value was observed at 247.5 kg N ha−1. Therefore, selecting N-efficient maize improves maize yield per unit area while reducing N fertiliser supply, especially at low N application rates.