Enhanced Maize Growth Research Articles

WITHDRAWN: Enhancing Maize Growth Under Drought and Lead Stress with Deashed Biochar and Growth-Promoting Rhizobacteria

The agricultural sector faces significant challenges due to water scarcity and increasing lead (Pb) contamination, adversely affecting crop productivity by generating reactive oxygen species (ROS) during Pb stress and drought. Biochar and plant growth-promoting rhizobacteria (PGPR) are emerging as effective tools to manage oxidative stress, yet the combined use of deashed biochar (BC) and PGPR remains underexplored. This study aimed to investigate the synergistic effects of BC and Agrobacterium fabrum on maize growth and biochemical attributes. Two levels of BC (control and 0.5%) were applied with and without A. fabrum under no Pb stress (0 mg Pb/kg soil) and 400 mg Pb/kg soil stress conditions. Additionally, seeds inoculated with A. fabrum were subjected to no drought stress (65% field capacity w/v) and drought stress (40% field capacity w/v). Conducted with three replicates in a randomized design within controlled greenhouse conditions, the study demonstrated that BC+A. fabrum treatment significantly improved maize germination (53.33%), shoot length (69.32%), root length (11.76%), and total soluble protein content (32.36%) under 400 mg Pb/kg soil stress compared to controls. Furthermore, BC+A. fabrum effectively mitigated drought stress, enhancing chlorophyll a (55.02%), chlorophyll b (50.61%), and total chlorophyll (53.37%) levels compared to controls. Analysis of key antioxidants (peroxidase, superoxide dismutase, catalase, and ascorbate peroxidase) revealed BC+A. fabrum ability to modulate antioxidant defenses in maize, underscoring its potential as a sustainable strategy to enhance maize growth resilience under combined Pb and drought stress conditions. Future studies should explore the long-term effects and field applicability of BC+A. fabrum treatments to optimize agricultural sustainability and productivity in Pb-contaminated and drought-prone environments.

Evaluation of the Impact of a Fertilizer Mixture from Plant Extracts and Urea on Corn Yield in Vietnam

This study evaluates the impact of a fertilizer mixture combining plant extracts and urea on the growth and yield of NK54 maize in Vietnam. The experimental design included five treatments with different combinations of urea and plant extracts, compared against a control treatment. Growth parameters such as plant height, leaf number, leaf area, and leaf area index (LAI) were monitored throughout the growing season. The results indicated that the application of urea-coated plant extracts significantly improved growth duration, plant height, and leaf development compared to conventional urea fertilization. Specifically, treatments using the urea-plant extract mixture achieved higher plant heights and leaf area, with Treatment T3 (9 ml concentrated extract + 1 kg Urea) showing the highest theoretical and actual yields. The theoretical yield ranged from 63.62 to 68 q/ha, and the actual yield ranged from 43.7 to 48.4 q/ha, with Treatment T3 consistently outperforming others. The findings suggest that integrating plant extracts with urea can enhance maize growth and yield, highlighting the importance of optimizing fertilization strategies for improving crop productivity.

Biochemical Traits and Biological Assessment of Indigenous Biofilm-Forming Rhizophosphate Bacteria Isolated from Salinity and Acidity Stressed Soils to Enhance Maize Growth

Biochemical Traits and Biological Assessment of Indigenous Biofilm-Forming Rhizophosphate Bacteria Isolated from Salinity and Acidity Stressed Soils to Enhance Maize Growth

Coordinated influence of Funneliformis mosseae and different plant growth-promoting bacteria on growth, root functional traits, and nutrient acquisition by maize.

Rhizospheric interactions among plant roots, arbuscular mycorrhizal fungi, and plant growth-promoting bacteria (PGPB) can enhance plant health by promoting nutrient acquisition and stimulating the plant immune system. This pot experiment, conducted in autoclaved soil, explored the synergistic impacts of the arbuscular mycorrhizal fungus Funneliformis mosseae with four individual bacterial strains, viz.: Cronobacter sp. Rz-7, Serratia sp. 5-D, Pseudomonas sp. ER-20 and Stenotrophomonas sp. RI-4A on maize growth, root functional traits, root exudates, root colonization, and nutrient uptake. The comprehensive biochemical characterization of these bacterial strains includes assessments of mineral nutrient solubilization, plant hormone production, and drought tolerance. The results showed that all single and interactive treatments of the mycorrhizal fungus and bacterial strains improved maize growth, as compared with the control (no fungus or PGPB). Among single treatments, the application of the mycorrhizal fungus was more effective than the bacterial strains in stimulating maize growth. Within the bacterial treatments, Serratia sp. 5-D and Pseudomonas sp. ER-20 were more effective in enhancing maize growth than Cronobacter sp. Rz-7 and Stenotrophomonas sp. RI-4A. All bacterial strains were compatible with Funneliformis mosseae to improve root colonization and maize growth. However, the interaction of mycorrhiza and Serratia sp. 5-D (M + 5-D) was the most prominent for maize growth improvement comparatively to all other treatments. We observed that bacterial strains directly enhanced maize growth while indirectly promoting biomass accumulation by facilitating increased mycorrhizal colonization, indicating that these bacteria acted as mycorrhizal helper bacteria.

Effect of tillage and precision nutrient placement on growth and productivity of maize (Zea mays)

The experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi during rainy season of 2022 to asses the effect of tillage and precise nutrient placement on maize (Zea mays L.) growth. Employing a split-plot design with 3-tillage methods in main plots, viz. T1 , (conventional tillage); T2 , (once rotavator as minimum tillage) and T3 , (zero tillage) and 4, precision nutrient application options N1 , 50% RDF as point placement; N2 , 75% RDF as band placement; N3, 100% RDF as band placement and N4, 100% RDF as broadcasting were tested in subplots. Results indicated that tillage and precision nutrient placement practices improved the plant height and LAI of maize. Minimum tillage recorded significantly higher crop growth indices, viz. CGR (1.92 g/m2/day), RGR (26.80 g/g/day) and dry matter accumulation (204.58 g/plant) over other tillage practices at 60 to 90 Days after sowing (DAS). Root attributes also improved under minimum tillage. The grain yield was significantly higher with minimum tillage (6.22 t/ha) over other tillage practices. Among the precision nutrient application options, 100% RDF as band placement recorded significantly higher grain yield (6.20 t/ha) over N2 and N4 but remained statistically at par with 50% RDF point placement (6.06 t/ha). The findings suggested that adopting minimum tillage and precise nutrient point placement could significantly enhance maize growth and yield in kharif seasons, offering 50% reduction in fertilizer consumption.

Exploring the potential of green synthesized cerium oxide nanoparticles in mitigating chromium toxicity in maize

ProblemChromium (Cr) contamination in agricultural soils poses a significant threat to maize productivity and food security, necessitating the development of innovative strategies to enhance Cr tolerance and mitigate its toxic effects on plant growth and development. ObjectiveThe aims of current study are the green synthesis of cerium oxide nanoparticles (CeO2 NPs) using Jasminum officinale L. plant extract and their application to alleviate chromium stress in maize plants. MethodsFourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and elemental mapping methods were used to characterize the synthesized CeO2 NPs. The cerium oxide NPs (0, 25, 75 and 100 mg/L) treatment levels applied through foliar and seed priming to check growth, physiological responses and metal uptake by maize plants and a fully random design was used to set up a factorial experiment. ResultsThe findings showed that foliar application of 100 mg/L CeO2 NPs resulted in an improvement in the plant height (43 %), shoot fresh plant (41 %) and root fresh weight (84 %), and total chlorophyll concentrations (67 %) in maize plants as compared to seed priming (as 25, 32, 40 and 43 % respectively). It also effectively enhanced antioxidant enzymes including super oxide dismutase (75 %) and peroxidase (79 %). In maize plants, by foliar application over the control, CeO2 NPs reduce electrolyte leakage (53 %), malondialdehyde contents (32 %), and chromium content in roots (70 %) under chromium stress. ConclusionTherefore, these results suggested that increase in the concentration of CeO2 NPs more efficiently 100 mg/L has high ability against chromium stress and act as a promising solution to reduce metal concentration, enhance maize growth and promote sustainable agriculture. SignificanceThis study’s implications for future research on CeO2 NPs include elucidating their mechanisms in plant stress tolerance, exploring interactive effects with heavy metals, and expanding their use in plant stress management. Furthermore, this finding develops a novel strategy for improving maize cultivation in Cr-contaminated soils, contributing to sustainable agriculture and food security.

Zea mays cultivation, biochar, and arbuscular mycorrhizal fungal inoculation influenced lead immobilization.

Plant cultivation can influence the immobilization of heavy metals in soil. However, the roles of soil amendments and microorganisms in crop-based phytoremediation require further exploration. In this study, we evaluated the impact of Zea mays L. cultivation, biochar application, and arbuscular mycorrhizal fungi (AMF) inoculation on soil lead (Pb) immobilization. Our results indicated that biochar addition resulted in a significant, 42.00%, reduction in AMF colonization. Plant cultivation, AMF inoculation, and biochar addition all contributed to enhanced Pb immobilization, as evidenced by decreased levels of diethylenetriaminepentaacetic acid- and CaCl2-extractable Pb in the soil. Furthermore, soil subjected to plant cultivation with AMF and biochar displayed reduced concentrations of bioavailable Pb. Biochar addition altered the distribution of Pb fractions in the soil, transforming the acid-soluble form into the relatively inert reducible and oxidizable forms. Additionally, biochar, AMF, and their combined use promoted maize growth parameters, including height, stem diameter, shoot and root biomass, and phosphorus uptake, while simultaneously reducing the shoot Pb concentration. These findings suggest a synergistic effect in Pb phytostabilization. In summary, despite the adverse impact of biochar on mycorrhizal growth, cultivating maize with the concurrent use of biochar and AMF emerges as a recommended and effective strategy for Pb phytoremediation.IMPORTANCEHeavy metal contamination in soil is a pressing environmental issue, and phytoremediation has emerged as a sustainable approach for mitigating this problem. This study sheds light on the potential of maize cultivation, biochar application, and arbuscular mycorrhizal fungi (AMF) inoculation to enhance the immobilization of Pb in contaminated soil. The findings demonstrate that the combined use of biochar and AMF during maize cultivation can significantly improve Pb immobilization and simultaneously enhance maize growth, offering a promising strategy for sustainable and effective Pb phytoremediation practices. This research contributes valuable insights into the field of phytoremediation and its potential to address heavy metal pollution in agricultural soils.

Enhancing nitrogen use efficiency and yield of maize (Zea mays L.) through Ammonia volatilization mitigation and nitrogen management approaches

Management of nitrogen (N) fertilizer is a critical factor that can improve maize (Zea mays L.) production. On the other hand, high volatilization losses of N also pollute the air. A field experiment was established using a silt clay soil to examine the effect of sulfur-coated urea and sulfur from gypsum on ammonia (NH3) emission, N use efficiency (NUE), and the productivity of maize crop under alkaline calcareous soil. The experimental design was a randomized complete block (RCBD) with seven treatments in three replicates: control with no N, urea150 alone (150 kg N ha−1), urea200 alone (200 kg N ha−1), urea150 + S (60 kg ha−1 S from gypsum), urea200 + S, SCU150 (sulfur-coated urea) and SCU200. The results showed that the urea150 + S and urea200 + S significantly reduced the total NH3 by (58 and 42%) as compared with the sole application urea200. The NH3 emission reduced further in the treatment with SCU150 and SCU200 by 74 and 65%, respectively, compared to the treatment with urea200. The maize plant biomass, grain yield, and total N uptake enhanced by 5–14%, 4–17%, and 7–13, respectively, in the treatments with urea150 + s and urea200 + S, relative to the treatment with urea200 alone. Biomass, grain yield, and total N uptake further increased significantly by 22–30%, 25–28%, and 26–31%, respectively, in the treatments with SCU150 and SCU200, relative to the treatment with urea200 alone. The applications of SCU150 enhanced the nitrogen use efficiency (NUE) by (72%) and SCU200 by (62%) respectively, compared with the sole application of urea200 alone. In conclusion, applying S-coated urea at a lower rate of 150 kg N ha−1 compared with a higher rate of 200 kg N ha−1 may be an effective way to reduce N fertilizer application rate and mitigate NH3 emission, improve NUE, and increase maize yield. More investigations are suggested under different soil textures and climatic conditions to declare S-coated urea at 150 kg N ha−1 as the best application rate for maize to enhance maize growth and yield.

Engineered Bacillus subtilis Biofilm@Biochar living materials for in-situ sensing and bioremediation of heavy metal ions pollution

The simultaneous sensing and remediation of multiple heavy metal ions in wastewater or soil with microorganisms is currently a significant challenge. In this study, the microorganism Bacillus subtilis was used as a chassis organism to construct two genetic circuits for sensing and adsorbing heavy-metal ions. The engineered biosensor can sense three heavy metal ions (0.1–75 μM of Pb2+ and Cu2+, 0.01–3.5 μM of Hg2+) in situ real-time with high sensitivity. The engineered B. subtilis TasA-metallothionein (TasA-MT) biofilm can specifically adsorb metal ions from the environment, exhibiting remarkable removal efficiencies of 99.5% for Pb2+, 99.9% for Hg2+and 99.5% for Cu2+ in water. Furthermore, this engineered strain (as a biosensor and absorber of Pb2+, Cu2+, and Hg2+) was incubated with biochar to form a hybrid biofilm@biochar (BBC) material that could be applied in the bioremediation of heavy metal ions. The results showed that BBC material not only significantly reduced exchangeable Pb2+ in the soil but also reduced Pb2+ accumulation in maize plants. In addition, it enhanced maize growth and biomass. In conclusion, this study examined the potential applications of biosensors and hybrid living materials constructed using sensing and adsorption circuits in B. subtilis, providing rapid and cost-effective tools for sensing and remediating multiple heavy metal ions (Pb2+, Hg2+, and Cu2+).

Harnessing the Synergy of the Cyanobacteria-Plant Growth Promoting Bacteria for Improved Maize (Zea mays) Growth and Soil Health

Intensive use of chemicals in agriculture harms the soil, disrupts the ecological balance, and impacts microorganisms. Biofertilizers are gaining traction due to their eco-friendly and cost-effective benefits. This study evaluates the potential of the cyanobacterium MACC-612 (Nostoc piscinale) and plant growth-promoting bacteria (PGPB) (Azospirillum lipoferum, Pseudomonas fluorescens) in enhancing crop growth, yield, and soil health. A two-year field study was conducted using a factorial approach and a completely randomized block design, comprising four replications. The three levels of the cynobacterium (0, 0.3, or 1 g/L of N. MACC-612) and different bacteria strains were used in the experiments. The results demonstrated substantial enhancements in seed number per ear, kernel weight, and yield when using N. piscinale and PGPB, whether used individually or in combination. The soil pH, humus, (NO3− + NO2−)-nitrogen, and soil microbial biomass showed significant increases across both years. The combining application of the N. piscinale (0.3 g/L) with A. lipoferum increased grain yield by 33.20% in the first year and 31.53% in the second. The humus and (NO3− + NO2−)-nitrogen content significantly rose in treatments involving N. piscinale at 0.3 g/L combined with A. lipoferum at about 20.25% and 59.2%, respectively, in comparison to the untreated control. Hence, the most effective approach was the combined use of N. piscinale and A. lipoferum, which enhanced maize growth and soil fertility.

Struvite/biochar composites as recovered phosphorus fertilizers from domestic sewage sludge increased biomass and nutrient uptake of maize

Global mines of phosphates, which are a main source for the manufacturing of phosphorus (P)-fertilizers, are running out. To solve this problem, the recovery of P by struvite (NH4MgPO4·6H2O) precipitation as a slow-release P-fertilizer (SRPF) has been a growing interest of recent research. This study aimed to assess the effect of struvite/biochar composites as SRPFs on the growth yield, nutrient uptake responses of maize in two soils (with different amounts of calcium carbonate equivalent), and calculation of P use efficiency indices. The greenhouse experiment was designed with six P fertilizer treatments, i.e. triple super-phosphate (TSP), four types of struvite/biochar composites (S/G0, S/G25, S/G50, and S/G75), and control (no P fertilizer applied) with three replication. Results showed that struvite/biochar composite with high amounts of biochar i.e. S/G75 is the best treatment for improving biomass’s of maize (63 and 39%), plant height (25 and 16%), SPAD value (31 and 26%) compared to control and TSP in soil-1 with the low amount of calcium carbonate equivalent, respectively. Applying S/G75, S/G50, S/G25, and S/G0 composites, and TSP concentration of P increased by 2, 1.85, 1.76, 1.73, and 1.34 times over control in soils, respectively. Using of composites significantly influenced P uptake, and recovery efficiency of P by plants, while the S/G75 composite was showed superior to other P-fertilizers. Overall, the struvite/biochar composites showed great potential as efficient SRPF for enhanced maize growth, and the presence of biochar in struvite composite with high amount (S/G75) increased the efficiency of fertilization in calcareous soil.

Limited effectiveness of selected bioeffectors combined with recycling phosphorus fertilizers for maize cultivation under Swiss farming conditions.

The use of plant biostimulants, also known as bioeffectors (BEs), has attracted increasing attention as an environmentally friendly strategy for more sustainable crop production. BEs are substances or microorganisms that are applied to plants or the surrounding soil to stimulate natural processes to enhance nutrient uptake, stress tolerance, and plant growth. Here, we tested the effectiveness of five BEs to enhance maize growth and phosphorus (P) uptake from various recycled P fertilizers in a series of pot and field experiments. First, the impact of two bacterial BEs and one soil-specific plant-based BE on crop performance was assessed in a 4-week screening experiment conducted in two arable, P-deficient soils of differing soil pH (a silty clay loam of pH 7.1 and a silty loam of pH 7.8) amended with recycled P-fertilizers (rock phosphate, biogas digestate, green waste compost, composted dairy manure, and chicken manure pellets). Then, for each soil type, the plant growth-promoting effect of the most promising BE-fertilizer combinations was re-assessed in an 8-week experiment. In addition, over a period of up to 3 years, three field experiments were conducted with maize in which up to two bacterial BEs were used either alone or in combination with a plant-based BE. Our experiments show that while BEs in combination with specific P-fertilizers can promote maize growth within the first weeks of growth under controlled conditions, the observed effects vanished in the long term, both in pots and under field conditions. In a tracing experiment, in which we tested the persistence of one bacterial BE over a period of 5 weeks, we observed a drastic decrease in colony-forming units already 2 weeks after inoculation. As previously shown in other studies, our data indicate that the plant growth-promoting effects of BEs found under controlled conditions are not directly transferable to field conditions. It is suggested that the drastic decline in inoculated bacterial strains in the tracing experiment is the reason for the decline in plant growth effect.

Organic Amendments promote saline-alkali soil desalinization and enhance maize growth.

Secondary soil salinization in arid and semi-arid regions is a serious problem that severely hampers local agricultural productivity and poses a threat to the long-term sustainability of food production. the utilization of organic soil amendments presents a promising approach to mitigate yield losses and promote sustainable agricultural production in saline-alkali soil. In this study, we established four distinct treatments, chemical fertilizer (CK), humic acid with chemical fertilizer (HA), carboxymethyl cellulose with chemical fertilizer (CMC), and amino acid with chemical fertilizer (AA), to elucidate their respective impacts on the reclamation of saline soil and the growth of maize. The findings of our study reveal notable variations in desalination rates within the 0-40 cm soil layer due to the application of distinct soil amendments, ranging from 11.66% to 37.17%. Moreover, application of amendments significantly increased the percentage of soil macro-aggregates as compared to the CK treatment. Furthermore, HA and AA treatments significantly augmented soil nutrient content (HA: 48.07%; AA: 39.50%), net photosynthetic rate (HA: 12.68%; AA: 13.94%), intercellular CO2 concentration (HA: 57.20%; AA: 35.93%) and maize yield (HA:18.32%; AA:16.81%). Correlation analysis and structural equation modeling unveiled diverse mechanisms of yield enhancement for HA, CMC, and AA treatments. HA enhanced yield by increasing organic matter and promoting soil aggregate formation, CMC improved soil water content and facilitated salt leaching due to its excellent water-holding properties, while AA increased yield by elevating soil organic matter and effective nitrogen content. Among the array of soil amendment materials scrutinized, HA treatment emerged as the most promising agent for enhancing soil conditions and is thus recommended as the preferred choice for treating local saline soils.

Agronomic Zn biofortification through nano ZnO application enhanced growth, photosystem efficiency, Zn and P nutrition in maize

ABSTRACT Zinc-oxide nanoparticles (ZnO-NP) effect on crop physiology and zinc recovery remains poorly studied for acidic-sandy soils. To address this, greenhouse pot (plastic-pots, 6 kg soil, maize) experiments with ZnO-NP (50, 100, 150, 200 mg kg−1) applied via different methods (soil-drench, seed-coating and foliar-spray) was conducted in a 60 days study. Results revealed that ZnO-NP via seed-coating (100 mg kg−1) and soil-drench (150 mg kg−1) enhanced shoot and total P uptake, while ZnO-NPs (foliar) (50 mg kg−1) enhanced maize growth (6–11%), with agronomic and physiological improvements ultimately resulted in greater biomass (16–20%), Zn agronomic efficiency and uptake. Compared to ZnSO4 treatment and the control, seed-coating with 100 mg kg−1 ZnO-NP increased leaf chlorophyll and pigment content by 12–127%. Principal component analysis revealed a close association among growth traits, plant pigments, fluorescence parameters, total Zn and P concentration, and uptake with total biomass as influenced by ZnO-NPs. Thus, compared to conventional ZnSO4 and higher dosages of ZnO-NPs, foliar-spray of ZnO-NP at 50 mg kg−1, seed-coating at 100 mg kg−1, or soil-drench at 150 mg kg−1 increased maize biochemical characteristics, growth, biomass, and Zn agronomic efficiency. These elucidate important implications of ZnO-NP application for increasing plant development and Zn biofortification in acidic-sandy soils.

Wheat Straw Biochar Produced at a Low Temperature Enhanced Maize Growth and Yield by Influencing Soil Properties of Typic calciargid

Arid and semi-arid soils are low in organic matter and have poor fertility, making them a serious threat to crop production. Most organic amendments, such as crop residues and farmyard manure, are short lived because of rapid decomposition. Incubation and pot studies were conducted to assess the impact of wheat straw biochar (produced at 350 °C) on temporal changes in soil microbial biomass and fertility status and to evaluate the efficacy of biochar for maize production in the top layer of Typic calciargid. The incubation study compared four levels of biochar (control, 0.5, 1.0 and 2.0% on a w/w basis of soil) and two fertilizer rates, i.e., unfertilized (no NPK fertilizer) and fertilized (nitrogen, P2O5 and K2O with rates of 125, 80 and 52.5 mg kg−1 soil, respectively). After incubation, the 2.0% biochar significantly improved the soil cation exchange capacity, organic carbon and microbial biomass carbon by up to 35, 59 and 26%, respectively, while decreasing the soil pH by up to 1.5% compared to that of the control treatment. When fertilized, the 2.0% biochar improved the soil’s available phosphorous, extractable potassium and total nitrogen by up to 59, 39 and 28%, respectively, compared to those of the control. The results from the pot experiment showed that using the 1% biochar with fertilizer significantly increased the maize dry biomass and grain yield by up to 57 and 72%, respectively, compared to those of the control. Additionally, the nitrogen and phosphorus recoveries from the mineral fertilizers improved significantly (up to 26 and 38%, respectively) when using the 1.0% biochar compared to those of the control. Conclusively, the addition of 1.0% biochar significantly improved maize growth and yield by enhancing nutrient recovery from mineral fertilizer and improving soil properties.

The Residual Impact of Goethite-Modified Biochar on Cadmium and Arsenic Uptake by Maize in Co-Contaminated Soil

ABSTRACT Cadmium (Cd) and arsenic (As) are toxic elements that threaten plants and human health. Due to the opposite transformations of Cd and As, their simultaneous immobilization poses numerous concerns. Thus, there is an urgent need to simultaneously reduce Cd and As mobility and plant uptake in co-contaminated soil. Our previous work found that goethite-modified biochar amendments effectively reduced Cd and As uptake by Chinese cabbage; however, their residual impact on subsequent crops must be investigated. In the current work, the following maize (Zea mays L.) was grown after Chinese cabbage in Cd and As co-contaminated soil amended by biochar (BC), goethite (G), and goethite-modified biochar (GBC) at a 1% application rate. The synthesis of GBCs involved two different initial mass ratios of iron/biochar (Fe/BC), with GBC1 having a Fe/BC ratio of 1:1 and GBC2 having a Fe/BC ratio of 2:1. The current study assessed the residual impacts of BC, G, and GBC amendments on Cd and As mobility, uptake by maize, and their impacts on maize growth. The results revealed that GBC amendments enhanced maize growth, chlorophyll content, and gas exchange parameters compared to raw BC and G. Moreover, the GBC1 amendment lowered Cd and As uptake by maize shoots (29.48% and 61.56%) and roots (33.07% and 37.32%), respectively, compared to unamended soil (CK). The GBC1 amendment decreased the bioaccessibility of Cd and As by 24.37% and 37.44%, respectively, compared with CK. In general, the results demonstrated that GBC has a significant residual impact on maize growth and Cd and As uptake in co-contaminated soil.

Biochar Amends Saline Soil and Enhances Maize Growth: Three-Year Field Experiment Findings

Soil salinization is a significant obstacle to agricultural development in arid and semiarid regions. While short-term experiments have demonstrated the effective improvement of saline soils through biochar amendment, the long-term efficacy in sustainably ameliorating such soils remains uncertain. Addressing this knowledge gap, this study investigated the long-term effects of biochar amendment in a field setting by applying different rates of biochar to a salt-affected soil and cultivating silage maize for three consecutive years. The comprehensive assessment includes not only maize growth but also changes in soil physical and chemical properties over the study period. The results reveal a notable elevation in maize above-ground dry matter, directly correlated to the enhanced uptake of nitrogen, phosphorous, and potassium. Additionally, biochar application improves saline soil physical properties, including reduced bulk density (1–23%), increased soil large pores (0.7–12%), and macroaggregates (24–141%), and chemical properties, including a decrease in exchangeable sodium percentage (35–48%), and an increase in soil total organic carbon (112–857%), total nitrogen (9–198%), available nitrogen (12–49%), phosphorus (141–538%) and potassium (57–895%). These improvements ultimately resulted in better maize growth. However, the amelioration effect of biochar on these soil properties gradually diminished over the three-year study. Consequently, this study suggests that biochar is a promising soil amendment that can enhance maize growth in saline soil for at least three years in a field experiment, providing valuable insights for sustainable agricultural practices in salt-affected regions.

Native endophytes from maize as potential biocontrol agents against bacterial top rot caused by cross-kingdom pathogen Klebsiella pneumoniae

Maize crop has been suffering huge economic loss due to bacterial top rot disease caused by emerging plant pathogen Klebsiella pneumoniae, which is most concerning and highly contagious to both humans and animals. At present, chemical control is considered as an important disease management approach, however biological control through native endophytes has not been reported yet. Here, initially we isolated 120 native endophytes from maize plants, and screened 12 endophytes with potential antagonistic effect in coculture assay against maize bacterial top rot pathogen. Based on strong antibacterial activity, three endophytes (MZ-4, YN-23, and F14) were selected to evaluate their plant growth-promoting traits and biocontrol efficiency through in-vitro and in-vivo antagonistic assays. The three strains could produce IAA with a maximum yield of 2.54 µg/ml, 2.96 µg/ml, 2.07 µg/ml, respectively and also inhibit the growth of 10 common plant pathogenic bacteria. In planta assay suggested that three endophytes enhanced maize growth and significantly suppressed the incidence of K. pneumoniae with control effect of about 81.2 %, 74.7 %, and 66.7 %, respectively. Lastly, selected isolates MZ-4, YN-23, and F14 were molecularly characterized and identified as Bacillus velezensis. To our knowledge, this is the first study reporting the application of maize endophyte B. velezensis as a biocontrol agent against emerging pathogen of maize bacterial top rot disease.

Physiological properties and genomic insights into the plant growth-promoting rhizobacterium Brevibacillus laterosporus K75 isolated from maize rhizosphere.

When looking for a safer alternative to pesticides that are potentially harmful to living organisms, one of the directions worth looking at are plant growth-promoting rhizobacteria. The purpose of the research was a comprehensive characterization of Brevibacillus laterosporus K75, a strain isolated from maize rhizosphere. Many studies have proved B. laterosporus to be a biocontrol agent; however, little is known about B. laterosporus as a plant growth-promoting rhizobacterium. Ninety strains were screened for plant growth-promoting activities. Four strains with the best plant growth-promoting traits (Rhodococcus qingshengii K8, Bacillus subtilis subsp. stercoris K73, Brevibacillus laterosporus K75, and Brevibacillus laterosporus K89) were used to research their effect on maize growth. Under sterile conditions, B. laterosporus K75 showed the best stimulatory effect, significantly improving the weight of roots, shoots and leaves, and considerably increasing content of chlorophyll. In unsterilized soil, B. laterosporus K75 significantly improved length of roots and weight of leaves compared to the K73, K89, and untreated control. Moreover, B. laterosporus K75 significantly increased specific leaf area compared to the untreated control and to other inoculant treatments. The genome of B. laterosporus K75 was compared to the recently published B. laterosporus MG64. Genome-mining displayed differences in identified plant growth-promoting genes and biosynthetic gene clusters of secondary metabolites. The B. laterosporus K75 genome possessed additional genes involved in indole-3-acetic acid production and phosphate solubilization that could be attributed to its ability to enhance maize growth. Our study demonstrated that B. laterosporus K75 is a promising candidate for use in inoculant formulation, effectively facilitating maize growth. © 2022 Society of Chemical Industry.

The Interactions between Arbuscular Mycorrhizal Fungi and Trichoderma longibrachiatum Enhance Maize Growth and Modulate Root Metabolome under Increasing Soil Salinity.

Trichoderma longibrachiatum sp. are free-living filamentous fungi which are common in agro-ecosystems. However, few studies thus far have examined the interaction between Trichoderma longibrachiatum and arbuscular mycorrhizal (AM) fungi in saline soil and their potential for improving plant stress tolerance. Here, single, dual-inoculated (T. longibrachiatum MF, AM fungal community or Glomus sp.), and non-inoculated maize (Zea may L.) were subjected to different salinity levels (0, 75, 150, and 225 mM NaCl) to test the synergistic effects of dual inoculants on maize plants in different salt stress conditions. Plant performance and metabolic profiles were compared to find the molecular mechanisms underlying plant protection against salt stress. The first experiment revealed that dual inoculation of an AM fungal community and T. longibrachiatum MF improved the biomass and K+/Na+ ratio in maize under non-saline conditions, and generally enhanced AM fungal growth in root and soil under all but the 225 mM NaCl conditions. However, MF inoculant did not influence the structure of AM fungal communities in maize roots. In the second experiment, dual inoculation of Glomus sp. and T. longibrachiatum MF increased maize plant biomass, K+/Na+ ratio, and AM fungal growth in root and soil significantly at both 0 and 75 mM NaCl conditions. We identified metabolic compounds differentially accumulated in dual-inoculated maize that may underline their enhanced maize plant tolerance to increasing soil salinity. Our data suggested that the combination of Glomus sp. and T. longibrachiatum leads to interactions, which may play a potential role in alleviating the stress and improve crop productivity in salt-affected soils.